~mysql/mysql-server/mysql-5.5

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */


/**
  @addtogroup Replication
  @{

  @file

  @brief Code to run the io thread and the sql thread on the
  replication slave.
*/

#include "sql_priv.h"
#include "my_global.h"
#include "slave.h"
#include "sql_parse.h"                         // execute_init_command
#include "sql_table.h"                         // mysql_rm_table
#include "rpl_mi.h"
#include "rpl_rli.h"
#include "sql_repl.h"
#include "rpl_filter.h"
#include "repl_failsafe.h"
#include "transaction.h"
#include <thr_alarm.h>
#include <my_dir.h>
#include <sql_common.h>
#include <errmsg.h>
#include <mysqld_error.h>
#include <mysys_err.h>
#include "rpl_handler.h"
#include <signal.h>
#include <mysql.h>
#include <myisam.h>

#include "sql_base.h"                           // close_thread_tables
#include "tztime.h"                             // struct Time_zone
#include "log_event.h"                          // Rotate_log_event,
                                                // Create_file_log_event,
                                                // Format_description_log_event

#ifdef HAVE_REPLICATION

#include "rpl_tblmap.h"
#include "debug_sync.h"

#define FLAGSTR(V,F) ((V)&(F)?#F" ":"")

#define MAX_SLAVE_RETRY_PAUSE 5
/*
  a parameter of sql_slave_killed() to defer the killed status
*/
#define SLAVE_WAIT_GROUP_DONE 60
bool use_slave_mask = 0;
MY_BITMAP slave_error_mask;
char slave_skip_error_names[SHOW_VAR_FUNC_BUFF_SIZE];

typedef bool (*CHECK_KILLED_FUNC)(THD*,void*);

char* slave_load_tmpdir = 0;
Master_info *active_mi= 0;
my_bool replicate_same_server_id;
ulonglong relay_log_space_limit = 0;

/*
  When slave thread exits, we need to remember the temporary tables so we
  can re-use them on slave start.

  TODO: move the vars below under Master_info
*/

int disconnect_slave_event_count = 0, abort_slave_event_count = 0;

static pthread_key(Master_info*, RPL_MASTER_INFO);

enum enum_slave_reconnect_actions
{
  SLAVE_RECON_ACT_REG= 0,
  SLAVE_RECON_ACT_DUMP= 1,
  SLAVE_RECON_ACT_EVENT= 2,
  SLAVE_RECON_ACT_MAX
};

enum enum_slave_reconnect_messages
{
  SLAVE_RECON_MSG_WAIT= 0,
  SLAVE_RECON_MSG_KILLED_WAITING= 1,
  SLAVE_RECON_MSG_AFTER= 2,
  SLAVE_RECON_MSG_FAILED= 3,
  SLAVE_RECON_MSG_COMMAND= 4,
  SLAVE_RECON_MSG_KILLED_AFTER= 5,
  SLAVE_RECON_MSG_MAX
};

static const char *reconnect_messages[SLAVE_RECON_ACT_MAX][SLAVE_RECON_MSG_MAX]=
{
  {
    "Waiting to reconnect after a failed registration on master",
    "Slave I/O thread killed while waitnig to reconnect after a failed \
registration on master",
    "Reconnecting after a failed registration on master",
    "failed registering on master, reconnecting to try again, \
log '%s' at position %s",
    "COM_REGISTER_SLAVE",
    "Slave I/O thread killed during or after reconnect"
  },
  {
    "Waiting to reconnect after a failed binlog dump request",
    "Slave I/O thread killed while retrying master dump",
    "Reconnecting after a failed binlog dump request",
    "failed dump request, reconnecting to try again, log '%s' at position %s",
    "COM_BINLOG_DUMP",
    "Slave I/O thread killed during or after reconnect"
  },
  {
    "Waiting to reconnect after a failed master event read",
    "Slave I/O thread killed while waiting to reconnect after a failed read",
    "Reconnecting after a failed master event read",
    "Slave I/O thread: Failed reading log event, reconnecting to retry, \
log '%s' at position %s",
    "",
    "Slave I/O thread killed during or after a reconnect done to recover from \
failed read"
  }
};
 

typedef enum { SLAVE_THD_IO, SLAVE_THD_SQL} SLAVE_THD_TYPE;

static int process_io_rotate(Master_info* mi, Rotate_log_event* rev);
static int process_io_create_file(Master_info* mi, Create_file_log_event* cev);
static bool wait_for_relay_log_space(Relay_log_info* rli);
static inline bool io_slave_killed(THD* thd,Master_info* mi);
static inline bool sql_slave_killed(THD* thd,Relay_log_info* rli);
static int init_slave_thread(THD* thd, SLAVE_THD_TYPE thd_type);
static void print_slave_skip_errors(void);
static int safe_connect(THD* thd, MYSQL* mysql, Master_info* mi);
static int safe_reconnect(THD* thd, MYSQL* mysql, Master_info* mi,
                          bool suppress_warnings);
static int connect_to_master(THD* thd, MYSQL* mysql, Master_info* mi,
                             bool reconnect, bool suppress_warnings);
static int safe_sleep(THD* thd, int sec, CHECK_KILLED_FUNC thread_killed,
                      void* thread_killed_arg);
static int get_master_version_and_clock(MYSQL* mysql, Master_info* mi);
static Log_event* next_event(Relay_log_info* rli);
static int queue_event(Master_info* mi,const char* buf,ulong event_len);
static int terminate_slave_thread(THD *thd,
                                  mysql_mutex_t *term_lock,
                                  mysql_cond_t *term_cond,
                                  volatile uint *slave_running,
                                  bool skip_lock);
static bool check_io_slave_killed(THD *thd, Master_info *mi, const char *info);

/*
  Find out which replications threads are running

  SYNOPSIS
    init_thread_mask()
    mask                Return value here
    mi                  master_info for slave
    inverse             If set, returns which threads are not running

  IMPLEMENTATION
    Get a bit mask for which threads are running so that we can later restart
    these threads.

  RETURN
    mask        If inverse == 0, running threads
                If inverse == 1, stopped threads
*/

void init_thread_mask(int* mask,Master_info* mi,bool inverse)
{
  bool set_io = mi->slave_running, set_sql = mi->rli.slave_running;
  register int tmp_mask=0;
  DBUG_ENTER("init_thread_mask");

  if (set_io)
    tmp_mask |= SLAVE_IO;
  if (set_sql)
    tmp_mask |= SLAVE_SQL;
  if (inverse)
    tmp_mask^= (SLAVE_IO | SLAVE_SQL);
  *mask = tmp_mask;
  DBUG_VOID_RETURN;
}


/*
  lock_slave_threads()
*/

void lock_slave_threads(Master_info* mi)
{
  DBUG_ENTER("lock_slave_threads");

  //TODO: see if we can do this without dual mutex
  mysql_mutex_lock(&mi->run_lock);
  mysql_mutex_lock(&mi->rli.run_lock);
  DBUG_VOID_RETURN;
}


/*
  unlock_slave_threads()
*/

void unlock_slave_threads(Master_info* mi)
{
  DBUG_ENTER("unlock_slave_threads");

  //TODO: see if we can do this without dual mutex
  mysql_mutex_unlock(&mi->rli.run_lock);
  mysql_mutex_unlock(&mi->run_lock);
  DBUG_VOID_RETURN;
}

#ifdef HAVE_PSI_INTERFACE
static PSI_thread_key key_thread_slave_io, key_thread_slave_sql;

static PSI_thread_info all_slave_threads[]=
{
  { &key_thread_slave_io, "slave_io", PSI_FLAG_GLOBAL},
  { &key_thread_slave_sql, "slave_sql", PSI_FLAG_GLOBAL}
};

static void init_slave_psi_keys(void)
{
  const char* category= "sql";
  int count;

  if (PSI_server == NULL)
    return;

  count= array_elements(all_slave_threads);
  PSI_server->register_thread(category, all_slave_threads, count);
}
#endif /* HAVE_PSI_INTERFACE */

/* Initialize slave structures */

int init_slave()
{
  DBUG_ENTER("init_slave");
  int error= 0;

#ifdef HAVE_PSI_INTERFACE
  init_slave_psi_keys();
#endif

  /*
    This is called when mysqld starts. Before client connections are
    accepted. However bootstrap may conflict with us if it does START SLAVE.
    So it's safer to take the lock.
  */
  mysql_mutex_lock(&LOCK_active_mi);
  /*
    TODO: re-write this to interate through the list of files
    for multi-master
  */
  active_mi= new Master_info(relay_log_recovery);

  if (pthread_key_create(&RPL_MASTER_INFO, NULL))
    goto err;

  /*
    If --slave-skip-errors=... was not used, the string value for the
    system variable has not been set up yet. Do it now.
  */
  if (!use_slave_mask)
  {
    print_slave_skip_errors();
  }

  /*
    If master_host is not specified, try to read it from the master_info file.
    If master_host is specified, create the master_info file if it doesn't
    exists.
  */
  if (!active_mi)
  {
    sql_print_error("Failed to allocate memory for the master info structure");
    error= 1;
    goto err;
  }

  if (init_master_info(active_mi,master_info_file,relay_log_info_file,
                       1, (SLAVE_IO | SLAVE_SQL)))
  {
    sql_print_error("Failed to initialize the master info structure");
    error= 1;
    goto err;
  }

  /* If server id is not set, start_slave_thread() will say it */

  if (active_mi->host[0] && !opt_skip_slave_start)
  {
    if (start_slave_threads(1 /* need mutex */,
                            0 /* no wait for start*/,
                            active_mi,
                            master_info_file,
                            relay_log_info_file,
                            SLAVE_IO | SLAVE_SQL))
    {
      sql_print_error("Failed to create slave threads");
      error= 1;
      goto err;
    }
  }

err:
  mysql_mutex_unlock(&LOCK_active_mi);
  DBUG_RETURN(error);
}

/*
  Updates the master info based on the information stored in the
  relay info and ignores relay logs previously retrieved by the IO 
  thread, which thus starts fetching again based on to the  
  group_master_log_pos and group_master_log_name. Eventually, the old
  relay logs will be purged by the normal purge mechanism.

  In the feature, we should improve this routine in order to avoid throwing
  away logs that are safely stored in the disk. Note also that this recovery 
  routine relies on the correctness of the relay-log.info and only tolerates 
  coordinate problems in master.info.
  
  In this function, there is no need for a mutex as the caller 
  (i.e. init_slave) already has one acquired.
  
  Specifically, the following structures are updated:
 
  1 - mi->master_log_pos  <-- rli->group_master_log_pos
  2 - mi->master_log_name <-- rli->group_master_log_name
  3 - It moves the relay log to the new relay log file, by
      rli->group_relay_log_pos  <-- BIN_LOG_HEADER_SIZE;
      rli->event_relay_log_pos  <-- BIN_LOG_HEADER_SIZE;
      rli->group_relay_log_name <-- rli->relay_log.get_log_fname();
      rli->event_relay_log_name <-- rli->relay_log.get_log_fname();
  
   If there is an error, it returns (1), otherwise returns (0).
 */
int init_recovery(Master_info* mi, const char** errmsg)
{
  DBUG_ENTER("init_recovery");
 
  Relay_log_info *rli= &mi->rli;
  if (rli->group_master_log_name[0])
  {
    mi->master_log_pos= max(BIN_LOG_HEADER_SIZE,
                             rli->group_master_log_pos);
    strmake(mi->master_log_name, rli->group_master_log_name,
            sizeof(mi->master_log_name)-1);
 
    sql_print_warning("Recovery from master pos %ld and file %s.",
                      (ulong) mi->master_log_pos, mi->master_log_name);
 
    strmake(rli->group_relay_log_name, rli->relay_log.get_log_fname(),
            sizeof(rli->group_relay_log_name)-1);
    strmake(rli->event_relay_log_name, rli->relay_log.get_log_fname(),
            sizeof(mi->rli.event_relay_log_name)-1);
 
    rli->group_relay_log_pos= rli->event_relay_log_pos= BIN_LOG_HEADER_SIZE;
  }

  DBUG_RETURN(0);
}
 
/**
  Convert slave skip errors bitmap into a printable string.
*/

static void print_slave_skip_errors(void)
{
  /*
    To be safe, we want 10 characters of room in the buffer for a number
    plus terminators. Also, we need some space for constant strings.
    10 characters must be sufficient for a number plus {',' | '...'}
    plus a NUL terminator. That is a max 6 digit number.
  */
  const size_t MIN_ROOM= 10;
  DBUG_ENTER("print_slave_skip_errors");
  DBUG_ASSERT(sizeof(slave_skip_error_names) > MIN_ROOM);
  DBUG_ASSERT(MAX_SLAVE_ERROR <= 999999); // 6 digits

  /* Make @@slave_skip_errors show the nice human-readable value.  */
  opt_slave_skip_errors= slave_skip_error_names;

  if (!use_slave_mask || bitmap_is_clear_all(&slave_error_mask))
  {
    /* purecov: begin tested */
    memcpy(slave_skip_error_names, STRING_WITH_LEN("OFF"));
    /* purecov: end */
  }
  else if (bitmap_is_set_all(&slave_error_mask))
  {
    /* purecov: begin tested */
    memcpy(slave_skip_error_names, STRING_WITH_LEN("ALL"));
    /* purecov: end */
  }
  else
  {
    char *buff= slave_skip_error_names;
    char *bend= buff + sizeof(slave_skip_error_names);
    int  errnum;

    for (errnum= 0; errnum < MAX_SLAVE_ERROR; errnum++)
    {
      if (bitmap_is_set(&slave_error_mask, errnum))
      {
        if (buff + MIN_ROOM >= bend)
          break; /* purecov: tested */
        buff= int10_to_str(errnum, buff, 10);
        *buff++= ',';
      }
    }
    if (buff != slave_skip_error_names)
      buff--; // Remove last ','
    if (errnum < MAX_SLAVE_ERROR)
    {
      /* Couldn't show all errors */
      buff= strmov(buff, "..."); /* purecov: tested */
    }
    *buff=0;
  }
  DBUG_PRINT("init", ("error_names: '%s'", slave_skip_error_names));
  DBUG_VOID_RETURN;
}

/*
  Init function to set up array for errors that should be skipped for slave

  SYNOPSIS
    init_slave_skip_errors()
    arg         List of errors numbers to skip, separated with ','

  NOTES
    Called from get_options() in mysqld.cc on start-up
*/

void init_slave_skip_errors(const char* arg)
{
  const char *p;
  DBUG_ENTER("init_slave_skip_errors");

  if (bitmap_init(&slave_error_mask,0,MAX_SLAVE_ERROR,0))
  {
    fprintf(stderr, "Badly out of memory, please check your system status\n");
    exit(1);
  }
  use_slave_mask = 1;
  for (;my_isspace(system_charset_info,*arg);++arg)
    /* empty */;
  if (!my_strnncoll(system_charset_info,(uchar*)arg,4,(const uchar*)"all",4))
  {
    bitmap_set_all(&slave_error_mask);
    print_slave_skip_errors();
    DBUG_VOID_RETURN;
  }
  for (p= arg ; *p; )
  {
    long err_code;
    if (!(p= str2int(p, 10, 0, LONG_MAX, &err_code)))
      break;
    if (err_code < MAX_SLAVE_ERROR)
       bitmap_set_bit(&slave_error_mask,(uint)err_code);
    while (!my_isdigit(system_charset_info,*p) && *p)
      p++;
  }
  /* Convert slave skip errors bitmap into a printable string. */
  print_slave_skip_errors();
  DBUG_VOID_RETURN;
}

static void set_thd_in_use_temporary_tables(Relay_log_info *rli)
{
  TABLE *table;

  for (table= rli->save_temporary_tables ; table ; table= table->next)
    table->in_use= rli->sql_thd;
}

int terminate_slave_threads(Master_info* mi,int thread_mask,bool skip_lock)
{
  DBUG_ENTER("terminate_slave_threads");

  if (!mi->inited)
    DBUG_RETURN(0); /* successfully do nothing */
  int error,force_all = (thread_mask & SLAVE_FORCE_ALL);
  mysql_mutex_t *sql_lock = &mi->rli.run_lock, *io_lock = &mi->run_lock;
  mysql_mutex_t *log_lock= mi->rli.relay_log.get_log_lock();

  if (thread_mask & (SLAVE_SQL|SLAVE_FORCE_ALL))
  {
    DBUG_PRINT("info",("Terminating SQL thread"));
    mi->rli.abort_slave=1;
    if ((error=terminate_slave_thread(mi->rli.sql_thd, sql_lock,
                                      &mi->rli.stop_cond,
                                      &mi->rli.slave_running,
                                      skip_lock)) &&
        !force_all)
      DBUG_RETURN(error);

    mysql_mutex_lock(log_lock);

    DBUG_PRINT("info",("Flushing relay-log info file."));
    if (current_thd)
      thd_proc_info(current_thd, "Flushing relay-log info file.");
    if (flush_relay_log_info(&mi->rli))
      DBUG_RETURN(ER_ERROR_DURING_FLUSH_LOGS);
    
    if (my_sync(mi->rli.info_fd, MYF(MY_WME)))
      DBUG_RETURN(ER_ERROR_DURING_FLUSH_LOGS);

    mysql_mutex_unlock(log_lock);
  }
  if (thread_mask & (SLAVE_IO|SLAVE_FORCE_ALL))
  {
    DBUG_PRINT("info",("Terminating IO thread"));
    mi->abort_slave=1;
    if ((error=terminate_slave_thread(mi->io_thd, io_lock,
                                      &mi->stop_cond,
                                      &mi->slave_running,
                                      skip_lock)) &&
        !force_all)
      DBUG_RETURN(error);

    mysql_mutex_lock(log_lock);

    DBUG_PRINT("info",("Flushing relay log and master info file."));
    if (current_thd)
      thd_proc_info(current_thd, "Flushing relay log and master info files.");
    if (flush_master_info(mi, TRUE, FALSE))
      DBUG_RETURN(ER_ERROR_DURING_FLUSH_LOGS);

    if (mi->rli.relay_log.is_open() &&
        my_sync(mi->rli.relay_log.get_log_file()->file, MYF(MY_WME)))
      DBUG_RETURN(ER_ERROR_DURING_FLUSH_LOGS);

    if (my_sync(mi->fd, MYF(MY_WME)))
      DBUG_RETURN(ER_ERROR_DURING_FLUSH_LOGS);

    mysql_mutex_unlock(log_lock);
  }
  DBUG_RETURN(0); 
}


/**
   Wait for a slave thread to terminate.

   This function is called after requesting the thread to terminate
   (by setting @c abort_slave member of @c Relay_log_info or @c
   Master_info structure to 1). Termination of the thread is
   controlled with the the predicate <code>*slave_running</code>.

   Function will acquire @c term_lock before waiting on the condition
   unless @c skip_lock is true in which case the mutex should be owned
   by the caller of this function and will remain acquired after
   return from the function.

   @param term_lock
          Associated lock to use when waiting for @c term_cond

   @param term_cond
          Condition that is signalled when the thread has terminated

   @param slave_running
          Pointer to predicate to check for slave thread termination

   @param skip_lock
          If @c true the lock will not be acquired before waiting on
          the condition. In this case, it is assumed that the calling
          function acquires the lock before calling this function.

   @retval 0 All OK ER_SLAVE_NOT_RUNNING otherwise.

   @note  If the executing thread has to acquire term_lock (skip_lock
          is false), the negative running status does not represent
          any issue therefore no error is reported.

 */
static int
terminate_slave_thread(THD *thd,
                       mysql_mutex_t *term_lock,
                       mysql_cond_t *term_cond,
                       volatile uint *slave_running,
                       bool skip_lock)
{
  DBUG_ENTER("terminate_slave_thread");
  if (!skip_lock)
  {
    mysql_mutex_lock(term_lock);
  }
  else
  {
    mysql_mutex_assert_owner(term_lock);
  }
  if (!*slave_running)
  {
    if (!skip_lock)
    {
      /*
        if run_lock (term_lock) is acquired locally then either
        slave_running status is fine
      */
      mysql_mutex_unlock(term_lock);
      DBUG_RETURN(0);
    }
    else
    {
      DBUG_RETURN(ER_SLAVE_NOT_RUNNING);
    }
  }
  DBUG_ASSERT(thd != 0);
  THD_CHECK_SENTRY(thd);

  /*
    Is is critical to test if the slave is running. Otherwise, we might
    be referening freed memory trying to kick it
  */

  while (*slave_running)                        // Should always be true
  {
    int error;
    DBUG_PRINT("loop", ("killing slave thread"));

    mysql_mutex_lock(&thd->LOCK_thd_data);
#ifndef DONT_USE_THR_ALARM
    /*
      Error codes from pthread_kill are:
      EINVAL: invalid signal number (can't happen)
      ESRCH: thread already killed (can happen, should be ignored)
    */
    int err __attribute__((unused))= pthread_kill(thd->real_id, thr_client_alarm);
    DBUG_ASSERT(err != EINVAL);
#endif
    thd->awake(THD::NOT_KILLED);
    mysql_mutex_unlock(&thd->LOCK_thd_data);

    /*
      There is a small chance that slave thread might miss the first
      alarm. To protect againts it, resend the signal until it reacts
    */
    struct timespec abstime;
    set_timespec(abstime,2);
    error= mysql_cond_timedwait(term_cond, term_lock, &abstime);
    DBUG_ASSERT(error == ETIMEDOUT || error == 0);
  }

  DBUG_ASSERT(*slave_running == 0);

  if (!skip_lock)
    mysql_mutex_unlock(term_lock);
  DBUG_RETURN(0);
}


int start_slave_thread(
#ifdef HAVE_PSI_INTERFACE
                       PSI_thread_key thread_key,
#endif
                       pthread_handler h_func, mysql_mutex_t *start_lock,
                       mysql_mutex_t *cond_lock,
                       mysql_cond_t *start_cond,
                       volatile uint *slave_running,
                       volatile ulong *slave_run_id,
                       Master_info* mi)
{
  pthread_t th;
  ulong start_id;
  DBUG_ENTER("start_slave_thread");

  DBUG_ASSERT(mi->inited);

  if (start_lock)
    mysql_mutex_lock(start_lock);
  if (!server_id)
  {
    if (start_cond)
      mysql_cond_broadcast(start_cond);
    if (start_lock)
      mysql_mutex_unlock(start_lock);
    sql_print_error("Server id not set, will not start slave");
    DBUG_RETURN(ER_BAD_SLAVE);
  }

  if (*slave_running)
  {
    if (start_cond)
      mysql_cond_broadcast(start_cond);
    if (start_lock)
      mysql_mutex_unlock(start_lock);
    DBUG_RETURN(ER_SLAVE_MUST_STOP);
  }
  start_id= *slave_run_id;
  DBUG_PRINT("info",("Creating new slave thread"));
  if (mysql_thread_create(thread_key,
                          &th, &connection_attrib, h_func, (void*)mi))
  {
    if (start_lock)
      mysql_mutex_unlock(start_lock);
    DBUG_RETURN(ER_SLAVE_THREAD);
  }
  if (start_cond && cond_lock) // caller has cond_lock
  {
    THD* thd = current_thd;
    while (start_id == *slave_run_id)
    {
      DBUG_PRINT("sleep",("Waiting for slave thread to start"));
      const char *old_msg= thd->enter_cond(start_cond, cond_lock,
                                           "Waiting for slave thread to start");
      /*
        It is not sufficient to test this at loop bottom. We must test
        it after registering the mutex in enter_cond(). If the kill
        happens after testing of thd->killed and before the mutex is
        registered, we could otherwise go waiting though thd->killed is
        set.
      */
      if (!thd->killed)
        mysql_cond_wait(start_cond, cond_lock);
      thd->exit_cond(old_msg);
      mysql_mutex_lock(cond_lock); // re-acquire it as exit_cond() released
      if (thd->killed)
      {
        if (start_lock)
          mysql_mutex_unlock(start_lock);
        DBUG_RETURN(thd->killed_errno());
      }
    }
  }
  if (start_lock)
    mysql_mutex_unlock(start_lock);
  DBUG_RETURN(0);
}


/*
  start_slave_threads()

  NOTES
    SLAVE_FORCE_ALL is not implemented here on purpose since it does not make
    sense to do that for starting a slave--we always care if it actually
    started the threads that were not previously running
*/

int start_slave_threads(bool need_slave_mutex, bool wait_for_start,
                        Master_info* mi, const char* master_info_fname,
                        const char* slave_info_fname, int thread_mask)
{
  mysql_mutex_t *lock_io=0, *lock_sql=0, *lock_cond_io=0, *lock_cond_sql=0;
  mysql_cond_t* cond_io=0, *cond_sql=0;
  int error=0;
  DBUG_ENTER("start_slave_threads");

  if (need_slave_mutex)
  {
    lock_io = &mi->run_lock;
    lock_sql = &mi->rli.run_lock;
  }
  if (wait_for_start)
  {
    cond_io = &mi->start_cond;
    cond_sql = &mi->rli.start_cond;
    lock_cond_io = &mi->run_lock;
    lock_cond_sql = &mi->rli.run_lock;
  }

  if (thread_mask & SLAVE_IO)
    error= start_slave_thread(
#ifdef HAVE_PSI_INTERFACE
                              key_thread_slave_io,
#endif
                              handle_slave_io, lock_io, lock_cond_io,
                              cond_io,
                              &mi->slave_running, &mi->slave_run_id,
                              mi);
  if (!error && (thread_mask & SLAVE_SQL))
  {
    error= start_slave_thread(
#ifdef HAVE_PSI_INTERFACE
                              key_thread_slave_sql,
#endif
                              handle_slave_sql, lock_sql, lock_cond_sql,
                              cond_sql,
                              &mi->rli.slave_running, &mi->rli.slave_run_id,
                              mi);
    if (error)
      terminate_slave_threads(mi, thread_mask & SLAVE_IO, !need_slave_mutex);
  }
  DBUG_RETURN(error);
}


/*
  Release slave threads at time of executing shutdown.

  SYNOPSIS
    end_slave()
*/

void end_slave()
{
  DBUG_ENTER("end_slave");

  /*
    This is called when the server terminates, in close_connections().
    It terminates slave threads. However, some CHANGE MASTER etc may still be
    running presently. If a START SLAVE was in progress, the mutex lock below
    will make us wait until slave threads have started, and START SLAVE
    returns, then we terminate them here.
  */
  mysql_mutex_lock(&LOCK_active_mi);
  if (active_mi)
  {
    /*
      TODO: replace the line below with
      list_walk(&master_list, (list_walk_action)end_slave_on_walk,0);
      once multi-master code is ready.
    */
    terminate_slave_threads(active_mi,SLAVE_FORCE_ALL);
  }
  mysql_mutex_unlock(&LOCK_active_mi);
  DBUG_VOID_RETURN;
}

/**
   Free all resources used by slave threads at time of executing shutdown.
   The routine must be called after all possible users of @c active_mi
   have left.

   SYNOPSIS
     close_active_mi()

*/
void close_active_mi()
{
  mysql_mutex_lock(&LOCK_active_mi);
  if (active_mi)
  {
    end_master_info(active_mi);
    delete active_mi;
    active_mi= 0;
  }
  mysql_mutex_unlock(&LOCK_active_mi);
}

static bool io_slave_killed(THD* thd, Master_info* mi)
{
  DBUG_ENTER("io_slave_killed");

  DBUG_ASSERT(mi->io_thd == thd);
  DBUG_ASSERT(mi->slave_running); // tracking buffer overrun
  DBUG_RETURN(mi->abort_slave || abort_loop || thd->killed);
}

/**
   The function analyzes a possible killed status and makes
   a decision whether to accept it or not.
   Normally upon accepting the sql thread goes to shutdown.
   In the event of deffering decision @rli->last_event_start_time waiting
   timer is set to force the killed status be accepted upon its expiration.

   @param thd   pointer to a THD instance
   @param rli   pointer to Relay_log_info instance

   @return TRUE the killed status is recognized, FALSE a possible killed
           status is deferred.
*/
static bool sql_slave_killed(THD* thd, Relay_log_info* rli)
{
  bool ret= FALSE;
  DBUG_ENTER("sql_slave_killed");

  DBUG_ASSERT(rli->sql_thd == thd);
  DBUG_ASSERT(rli->slave_running == 1);// tracking buffer overrun
  if (abort_loop || thd->killed || rli->abort_slave)
  {
    /*
      The transaction should always be binlogged if OPTION_KEEP_LOG is set
      (it implies that something can not be rolled back). And such case
      should be regarded similarly as modifing a non-transactional table
      because retrying of the transaction will lead to an error or inconsistency
      as well.
      Example: OPTION_KEEP_LOG is set if a temporary table is created or dropped.
    */
    if ((thd->transaction.all.modified_non_trans_table ||
         (thd->variables.option_bits & OPTION_KEEP_LOG))
        && rli->is_in_group())
    {
      char msg_stopped[]=
        "... Slave SQL Thread stopped with incomplete event group "
        "having non-transactional changes. "
        "If the group consists solely of row-based events, you can try "
        "to restart the slave with --slave-exec-mode=IDEMPOTENT, which "
        "ignores duplicate key, key not found, and similar errors (see "
        "documentation for details).";

      if (rli->abort_slave)
      {
        DBUG_PRINT("info", ("Request to stop slave SQL Thread received while "
                            "applying a group that has non-transactional "
                            "changes; waiting for completion of the group ... "));

        /*
          Slave sql thread shutdown in face of unfinished group modified 
          Non-trans table is handled via a timer. The slave may eventually
          give out to complete the current group and in that case there
          might be issues at consequent slave restart, see the error message.
          WL#2975 offers a robust solution requiring to store the last exectuted
          event's coordinates along with the group's coordianates
          instead of waiting with @c last_event_start_time the timer.
        */

        if (rli->last_event_start_time == 0)
          rli->last_event_start_time= my_time(0);
        ret= difftime(my_time(0), rli->last_event_start_time) <=
          SLAVE_WAIT_GROUP_DONE ? FALSE : TRUE;

        DBUG_EXECUTE_IF("stop_slave_middle_group", 
                        DBUG_EXECUTE_IF("incomplete_group_in_relay_log",
                                        ret= TRUE;);); // time is over

        if (ret == 0)
        {
          rli->report(WARNING_LEVEL, 0,
                      "Request to stop slave SQL Thread received while "
                      "applying a group that has non-transactional "
                      "changes; waiting for completion of the group ... ");
        }
        else
        {
          rli->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
                      ER(ER_SLAVE_FATAL_ERROR), msg_stopped);
        }
      }
      else
      {
        ret= TRUE;
        rli->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR, ER(ER_SLAVE_FATAL_ERROR),
                    msg_stopped);
      }
    }
    else
    {
      ret= TRUE;
    }
  }
  if (ret)
    rli->last_event_start_time= 0;
  
  DBUG_RETURN(ret);
}


/*
  skip_load_data_infile()

  NOTES
    This is used to tell a 3.23 master to break send_file()
*/

void skip_load_data_infile(NET *net)
{
  DBUG_ENTER("skip_load_data_infile");

  (void)net_request_file(net, "/dev/null");
  (void)my_net_read(net);                               // discard response
  (void)net_write_command(net, 0, (uchar*) "", 0, (uchar*) "", 0); // ok
  DBUG_VOID_RETURN;
}


bool net_request_file(NET* net, const char* fname)
{
  DBUG_ENTER("net_request_file");
  DBUG_RETURN(net_write_command(net, 251, (uchar*) fname, strlen(fname),
                                (uchar*) "", 0));
}

/*
  From other comments and tests in code, it looks like
  sometimes Query_log_event and Load_log_event can have db == 0
  (see rewrite_db() above for example)
  (cases where this happens are unclear; it may be when the master is 3.23).
*/

const char *print_slave_db_safe(const char* db)
{
  DBUG_ENTER("*print_slave_db_safe");

  DBUG_RETURN((db ? db : ""));
}

int init_strvar_from_file(char *var, int max_size, IO_CACHE *f,
                                 const char *default_val)
{
  uint length;
  DBUG_ENTER("init_strvar_from_file");

  if ((length=my_b_gets(f,var, max_size)))
  {
    char* last_p = var + length -1;
    if (*last_p == '\n')
      *last_p = 0; // if we stopped on newline, kill it
    else
    {
      /*
        If we truncated a line or stopped on last char, remove all chars
        up to and including newline.
      */
      int c;
      while (((c=my_b_get(f)) != '\n' && c != my_b_EOF)) ;
    }
    DBUG_RETURN(0);
  }
  else if (default_val)
  {
    strmake(var,  default_val, max_size-1);
    DBUG_RETURN(0);
  }
  DBUG_RETURN(1);
}


int init_intvar_from_file(int* var, IO_CACHE* f, int default_val)
{
  char buf[32];
  DBUG_ENTER("init_intvar_from_file");


  if (my_b_gets(f, buf, sizeof(buf)))
  {
    *var = atoi(buf);
    DBUG_RETURN(0);
  }
  else if (default_val)
  {
    *var = default_val;
    DBUG_RETURN(0);
  }
  DBUG_RETURN(1);
}

int init_floatvar_from_file(float* var, IO_CACHE* f, float default_val)
{
  char buf[16];
  DBUG_ENTER("init_floatvar_from_file");


  if (my_b_gets(f, buf, sizeof(buf)))
  {
    if (sscanf(buf, "%f", var) != 1)
      DBUG_RETURN(1);
    else
      DBUG_RETURN(0);
  }
  else if (default_val != 0.0)
  {
    *var = default_val;
    DBUG_RETURN(0);
  }
  DBUG_RETURN(1);
}


/**
   A master info read method

   This function is called from @c init_master_info() along with
   relatives to restore some of @c active_mi members.
   Particularly, this function is responsible for restoring
   IGNORE_SERVER_IDS list of servers whose events the slave is
   going to ignore (to not log them in the relay log).
   Items being read are supposed to be decimal output of values of a
   type shorter or equal of @c long and separated by the single space.

   @param arr         @c DYNAMIC_ARRAY pointer to storage for servers id
   @param f           @c IO_CACHE pointer to the source file

   @retval 0         All OK
   @retval non-zero  An error
*/

int init_dynarray_intvar_from_file(DYNAMIC_ARRAY* arr, IO_CACHE* f)
{
  int ret= 0;
  char buf[16 * (sizeof(long)*4 + 1)]; // static buffer to use most of times
  char *buf_act= buf; // actual buffer can be dynamic if static is short
  char *token, *last;
  uint num_items;     // number of items of `arr'
  size_t read_size;
  DBUG_ENTER("init_dynarray_intvar_from_file");

  if ((read_size= my_b_gets(f, buf_act, sizeof(buf))) == 0)
  {
    return 0; // no line in master.info
  }
  if (read_size + 1 == sizeof(buf) && buf[sizeof(buf) - 2] != '\n')
  {
    /*
      short read happend; allocate sufficient memory and make the 2nd read
    */
    char buf_work[(sizeof(long)*3 + 1)*16];
    memcpy(buf_work, buf, sizeof(buf_work));
    num_items= atoi(strtok_r(buf_work, " ", &last));
    size_t snd_size;
    /*
      max size lower bound approximate estimation bases on the formula:
      (the items number + items themselves) * 
          (decimal size + space) - 1 + `\n' + '\0'
    */
    size_t max_size= (1 + num_items) * (sizeof(long)*3 + 1) + 1;
    buf_act= (char*) my_malloc(max_size, MYF(MY_WME));
    memcpy(buf_act, buf, read_size);
    snd_size= my_b_gets(f, buf_act + read_size, max_size - read_size);
    if (snd_size == 0 ||
        ((snd_size + 1 == max_size - read_size) &&  buf[max_size - 2] != '\n'))
    {
      /*
        failure to make the 2nd read or short read again
      */
      ret= 1;
      goto err;
    }
  }
  token= strtok_r(buf_act, " ", &last);
  if (token == NULL)
  {
    ret= 1;
    goto err;
  }
  num_items= atoi(token);
  for (uint i=0; i < num_items; i++)
  {
    token= strtok_r(NULL, " ", &last);
    if (token == NULL)
    {
      ret= 1;
      goto err;
    }
    else
    {
      ulong val= atol(token);
      insert_dynamic(arr, (uchar *) &val);
    }
  }
err:
  if (buf_act != buf)
    my_free(buf_act);
  DBUG_RETURN(ret);
}


/*
  Check if the error is caused by network.
  @param[in]   errorno   Number of the error.
  RETURNS:
  TRUE         network error
  FALSE        not network error
*/

bool is_network_error(uint errorno)
{ 
  if (errorno == CR_CONNECTION_ERROR || 
      errorno == CR_CONN_HOST_ERROR ||
      errorno == CR_SERVER_GONE_ERROR ||
      errorno == CR_SERVER_LOST ||
      errorno == ER_CON_COUNT_ERROR ||
      errorno == ER_SERVER_SHUTDOWN)
    return TRUE;

  return FALSE;   
}


/*
  Note that we rely on the master's version (3.23, 4.0.14 etc) instead of
  relying on the binlog's version. This is not perfect: imagine an upgrade
  of the master without waiting that all slaves are in sync with the master;
  then a slave could be fooled about the binlog's format. This is what happens
  when people upgrade a 3.23 master to 4.0 without doing RESET MASTER: 4.0
  slaves are fooled. So we do this only to distinguish between 3.23 and more
  recent masters (it's too late to change things for 3.23).

  RETURNS
  0       ok
  1       error
  2       transient network problem, the caller should try to reconnect
*/

static int get_master_version_and_clock(MYSQL* mysql, Master_info* mi)
{
  char err_buff[MAX_SLAVE_ERRMSG];
  const char* errmsg= 0;
  int err_code= 0;
  MYSQL_RES *master_res= 0;
  MYSQL_ROW master_row;
  DBUG_ENTER("get_master_version_and_clock");

  /*
    Free old description_event_for_queue (that is needed if we are in
    a reconnection).
  */
  delete mi->rli.relay_log.description_event_for_queue;
  mi->rli.relay_log.description_event_for_queue= 0;

  if (!my_isdigit(&my_charset_bin,*mysql->server_version))
  {
    errmsg = "Master reported unrecognized MySQL version";
    err_code= ER_SLAVE_FATAL_ERROR;
    sprintf(err_buff, ER(err_code), errmsg);
  }
  else
  {
    /*
      Note the following switch will bug when we have MySQL branch 30 ;)
    */
    switch (*mysql->server_version)
    {
    case '0':
    case '1':
    case '2':
      errmsg = "Master reported unrecognized MySQL version";
      err_code= ER_SLAVE_FATAL_ERROR;
      sprintf(err_buff, ER(err_code), errmsg);
      break;
    case '3':
      mi->rli.relay_log.description_event_for_queue= new
        Format_description_log_event(1, mysql->server_version);
      break;
    case '4':
      mi->rli.relay_log.description_event_for_queue= new
        Format_description_log_event(3, mysql->server_version);
      break;
    default:
      /*
        Master is MySQL >=5.0. Give a default Format_desc event, so that we can
        take the early steps (like tests for "is this a 3.23 master") which we
        have to take before we receive the real master's Format_desc which will
        override this one. Note that the Format_desc we create below is garbage
        (it has the format of the *slave*); it's only good to help know if the
        master is 3.23, 4.0, etc.
      */
      mi->rli.relay_log.description_event_for_queue= new
        Format_description_log_event(4, mysql->server_version);
      break;
    }
  }

  /*
     This does not mean that a 5.0 slave will be able to read a 6.0 master; but
     as we don't know yet, we don't want to forbid this for now. If a 5.0 slave
     can't read a 6.0 master, this will show up when the slave can't read some
     events sent by the master, and there will be error messages.
  */

  if (errmsg)
    goto err;

  /* as we are here, we tried to allocate the event */
  if (!mi->rli.relay_log.description_event_for_queue)
  {
    errmsg= "default Format_description_log_event";
    err_code= ER_SLAVE_CREATE_EVENT_FAILURE;
    sprintf(err_buff, ER(err_code), errmsg);
    goto err;
  }

  /*
    Compare the master and slave's clock. Do not die if master's clock is
    unavailable (very old master not supporting UNIX_TIMESTAMP()?).
  */

  DBUG_EXECUTE_IF("dbug.before_get_UNIX_TIMESTAMP",
                  {
                    const char act[]=
                      "now "
                      "wait_for signal.get_unix_timestamp";
                    DBUG_ASSERT(opt_debug_sync_timeout > 0);
                    DBUG_ASSERT(!debug_sync_set_action(current_thd,
                                                       STRING_WITH_LEN(act)));
                  };);

  master_res= NULL;
  if (!mysql_real_query(mysql, STRING_WITH_LEN("SELECT UNIX_TIMESTAMP()")) &&
      (master_res= mysql_store_result(mysql)) &&
      (master_row= mysql_fetch_row(master_res)))
  {
    mi->clock_diff_with_master=
      (long) (time((time_t*) 0) - strtoul(master_row[0], 0, 10));
  }
  else if (check_io_slave_killed(mi->io_thd, mi, NULL))
    goto slave_killed_err;
  else if (is_network_error(mysql_errno(mysql)))
  {
    mi->report(WARNING_LEVEL, mysql_errno(mysql),
               "Get master clock failed with error: %s", mysql_error(mysql));
    goto network_err;
  }
  else 
  {
    mi->clock_diff_with_master= 0; /* The "most sensible" value */
    sql_print_warning("\"SELECT UNIX_TIMESTAMP()\" failed on master, "
                      "do not trust column Seconds_Behind_Master of SHOW "
                      "SLAVE STATUS. Error: %s (%d)",
                      mysql_error(mysql), mysql_errno(mysql));
  }
  if (master_res)
  {
    mysql_free_result(master_res);
    master_res= NULL;
  }

  /*
    Check that the master's server id and ours are different. Because if they
    are equal (which can result from a simple copy of master's datadir to slave,
    thus copying some my.cnf), replication will work but all events will be
    skipped.
    Do not die if SHOW VARIABLES LIKE 'SERVER_ID' fails on master (very old
    master?).
    Note: we could have put a @@SERVER_ID in the previous SELECT
    UNIX_TIMESTAMP() instead, but this would not have worked on 3.23 masters.
  */
  DBUG_EXECUTE_IF("dbug.before_get_SERVER_ID",
                  {
                    const char act[]=
                      "now "
                      "wait_for signal.get_server_id";
                    DBUG_ASSERT(opt_debug_sync_timeout > 0);
                    DBUG_ASSERT(!debug_sync_set_action(current_thd, 
                                                       STRING_WITH_LEN(act)));
                  };);
  master_res= NULL;
  master_row= NULL;
  if (!mysql_real_query(mysql,
                        STRING_WITH_LEN("SHOW VARIABLES LIKE 'SERVER_ID'")) &&
      (master_res= mysql_store_result(mysql)) &&
      (master_row= mysql_fetch_row(master_res)))
  {
    if ((::server_id == (mi->master_id= strtoul(master_row[1], 0, 10))) &&
        !mi->rli.replicate_same_server_id)
    {
      errmsg= "The slave I/O thread stops because master and slave have equal \
MySQL server ids; these ids must be different for replication to work (or \
the --replicate-same-server-id option must be used on slave but this does \
not always make sense; please check the manual before using it).";
      err_code= ER_SLAVE_FATAL_ERROR;
      sprintf(err_buff, ER(err_code), errmsg);
      goto err;
    }
  }
  else if (mysql_errno(mysql))
  {
    if (check_io_slave_killed(mi->io_thd, mi, NULL))
      goto slave_killed_err;
    else if (is_network_error(mysql_errno(mysql)))
    {
      mi->report(WARNING_LEVEL, mysql_errno(mysql),
                 "Get master SERVER_ID failed with error: %s", mysql_error(mysql));
      goto network_err;
    }
    /* Fatal error */
    errmsg= "The slave I/O thread stops because a fatal error is encountered \
when it try to get the value of SERVER_ID variable from master.";
    err_code= mysql_errno(mysql);
    sprintf(err_buff, "%s Error: %s", errmsg, mysql_error(mysql));
    goto err;
  }
  else if (!master_row && master_res)
  {
    mi->report(WARNING_LEVEL, ER_UNKNOWN_SYSTEM_VARIABLE,
               "Unknown system variable 'SERVER_ID' on master, \
maybe it is a *VERY OLD MASTER*.");
  }
  if (master_res)
  {
    mysql_free_result(master_res);
    master_res= NULL;
  }
  if (mi->master_id == 0 && mi->ignore_server_ids.elements > 0)
  {
    errmsg= "Slave configured with server id filtering could not detect the master server id.";
    err_code= ER_SLAVE_FATAL_ERROR;
    sprintf(err_buff, ER(err_code), errmsg);
    goto err;
  }

  /*
    Check that the master's global character_set_server and ours are the same.
    Not fatal if query fails (old master?).
    Note that we don't check for equality of global character_set_client and
    collation_connection (neither do we prevent their setting in
    set_var.cc). That's because from what I (Guilhem) have tested, the global
    values of these 2 are never used (new connections don't use them).
    We don't test equality of global collation_database either as it's is
    going to be deprecated (made read-only) in 4.1 very soon.
    The test is only relevant if master < 5.0.3 (we'll test only if it's older
    than the 5 branch; < 5.0.3 was alpha...), as >= 5.0.3 master stores
    charset info in each binlog event.
    We don't do it for 3.23 because masters <3.23.50 hang on
    SELECT @@unknown_var (BUG#7965 - see changelog of 3.23.50). So finally we
    test only if master is 4.x.
  */

  /* redundant with rest of code but safer against later additions */
  if (*mysql->server_version == '3')
    goto err;

  if (*mysql->server_version == '4')
  {
    master_res= NULL;
    if (!mysql_real_query(mysql,
                          STRING_WITH_LEN("SELECT @@GLOBAL.COLLATION_SERVER")) &&
        (master_res= mysql_store_result(mysql)) &&
        (master_row= mysql_fetch_row(master_res)))
    {
      if (strcmp(master_row[0], global_system_variables.collation_server->name))
      {
        errmsg= "The slave I/O thread stops because master and slave have \
different values for the COLLATION_SERVER global variable. The values must \
be equal for the Statement-format replication to work";
        err_code= ER_SLAVE_FATAL_ERROR;
        sprintf(err_buff, ER(err_code), errmsg);
        goto err;
      }
    }
    else if (check_io_slave_killed(mi->io_thd, mi, NULL))
      goto slave_killed_err;
    else if (is_network_error(mysql_errno(mysql)))
    {
      mi->report(WARNING_LEVEL, mysql_errno(mysql),
                 "Get master COLLATION_SERVER failed with error: %s", mysql_error(mysql));
      goto network_err;
    }
    else if (mysql_errno(mysql) != ER_UNKNOWN_SYSTEM_VARIABLE)
    {
      /* Fatal error */
      errmsg= "The slave I/O thread stops because a fatal error is encountered \
when it try to get the value of COLLATION_SERVER global variable from master.";
      err_code= mysql_errno(mysql);
      sprintf(err_buff, "%s Error: %s", errmsg, mysql_error(mysql));
      goto err;
    }
    else
      mi->report(WARNING_LEVEL, ER_UNKNOWN_SYSTEM_VARIABLE,
                 "Unknown system variable 'COLLATION_SERVER' on master, \
maybe it is a *VERY OLD MASTER*. *NOTE*: slave may experience \
inconsistency if replicated data deals with collation.");

    if (master_res)
    {
      mysql_free_result(master_res);
      master_res= NULL;
    }
  }

  /*
    Perform analogous check for time zone. Theoretically we also should
    perform check here to verify that SYSTEM time zones are the same on
    slave and master, but we can't rely on value of @@system_time_zone
    variable (it is time zone abbreviation) since it determined at start
    time and so could differ for slave and master even if they are really
    in the same system time zone. So we are omiting this check and just
    relying on documentation. Also according to Monty there are many users
    who are using replication between servers in various time zones. Hence
    such check will broke everything for them. (And now everything will
    work for them because by default both their master and slave will have
    'SYSTEM' time zone).
    This check is only necessary for 4.x masters (and < 5.0.4 masters but
    those were alpha).
  */
  if (*mysql->server_version == '4')
  {
    master_res= NULL;
    if (!mysql_real_query(mysql, STRING_WITH_LEN("SELECT @@GLOBAL.TIME_ZONE")) &&
        (master_res= mysql_store_result(mysql)) &&
        (master_row= mysql_fetch_row(master_res)))
    {
      if (strcmp(master_row[0],
                 global_system_variables.time_zone->get_name()->ptr()))
      {
        errmsg= "The slave I/O thread stops because master and slave have \
different values for the TIME_ZONE global variable. The values must \
be equal for the Statement-format replication to work";
        err_code= ER_SLAVE_FATAL_ERROR;
        sprintf(err_buff, ER(err_code), errmsg);
        goto err;
      }
    }
    else if (check_io_slave_killed(mi->io_thd, mi, NULL))
      goto slave_killed_err;
    else if (is_network_error(mysql_errno(mysql)))
    {
      mi->report(WARNING_LEVEL, mysql_errno(mysql),
                 "Get master TIME_ZONE failed with error: %s", mysql_error(mysql));
      goto network_err;
    } 
    else
    {
      /* Fatal error */
      errmsg= "The slave I/O thread stops because a fatal error is encountered \
when it try to get the value of TIME_ZONE global variable from master.";
      err_code= mysql_errno(mysql);
      sprintf(err_buff, "%s Error: %s", errmsg, mysql_error(mysql));
      goto err;
    }
    if (master_res)
    {
      mysql_free_result(master_res);
      master_res= NULL;
    }
  }

  if (mi->heartbeat_period != 0.0)
  {
    char llbuf[22];
    const char query_format[]= "SET @master_heartbeat_period= %s";
    char query[sizeof(query_format) - 2 + sizeof(llbuf)];
    /* 
       the period is an ulonglong of nano-secs. 
    */
    llstr((ulonglong) (mi->heartbeat_period*1000000000UL), llbuf);
    sprintf(query, query_format, llbuf);

    if (mysql_real_query(mysql, query, strlen(query))
        && !check_io_slave_killed(mi->io_thd, mi, NULL))
    {
      errmsg= "The slave I/O thread stops because SET @master_heartbeat_period "
        "on master failed.";
      err_code= ER_SLAVE_FATAL_ERROR;
      sprintf(err_buff, "%s Error: %s", errmsg, mysql_error(mysql));
      mysql_free_result(mysql_store_result(mysql));
      goto err;
    }
    mysql_free_result(mysql_store_result(mysql));
  }
 

err:
  if (errmsg)
  {
    if (master_res)
      mysql_free_result(master_res);
    DBUG_ASSERT(err_code != 0);
    mi->report(ERROR_LEVEL, err_code, "%s", err_buff);
    DBUG_RETURN(1);
  }

  DBUG_RETURN(0);

network_err:
  if (master_res)
    mysql_free_result(master_res);
  DBUG_RETURN(2);

slave_killed_err:
  if (master_res)
    mysql_free_result(master_res);
  DBUG_RETURN(2);
}

static bool wait_for_relay_log_space(Relay_log_info* rli)
{
  bool slave_killed=0;
  Master_info* mi = rli->mi;
  const char *save_proc_info;
  THD* thd = mi->io_thd;
  DBUG_ENTER("wait_for_relay_log_space");

  mysql_mutex_lock(&rli->log_space_lock);
  save_proc_info= thd->enter_cond(&rli->log_space_cond,
                                  &rli->log_space_lock,
                                  "\
Waiting for the slave SQL thread to free enough relay log space");
  while (rli->log_space_limit < rli->log_space_total &&
         !(slave_killed=io_slave_killed(thd,mi)) &&
         !rli->ignore_log_space_limit)
    mysql_cond_wait(&rli->log_space_cond, &rli->log_space_lock);
  thd->exit_cond(save_proc_info);
  DBUG_RETURN(slave_killed);
}


/*
  Builds a Rotate from the ignored events' info and writes it to relay log.

  SYNOPSIS
  write_ignored_events_info_to_relay_log()
    thd             pointer to I/O thread's thd
    mi

  DESCRIPTION
    Slave I/O thread, going to die, must leave a durable trace of the
    ignored events' end position for the use of the slave SQL thread, by
    calling this function. Only that thread can call it (see assertion).
 */
static void write_ignored_events_info_to_relay_log(THD *thd, Master_info *mi)
{
  Relay_log_info *rli= &mi->rli;
  mysql_mutex_t *log_lock= rli->relay_log.get_log_lock();
  DBUG_ENTER("write_ignored_events_info_to_relay_log");

  DBUG_ASSERT(thd == mi->io_thd);
  mysql_mutex_lock(log_lock);
  if (rli->ign_master_log_name_end[0])
  {
    DBUG_PRINT("info",("writing a Rotate event to track down ignored events"));
    Rotate_log_event *ev= new Rotate_log_event(rli->ign_master_log_name_end,
                                               0, rli->ign_master_log_pos_end,
                                               Rotate_log_event::DUP_NAME);
    rli->ign_master_log_name_end[0]= 0;
    /* can unlock before writing as slave SQL thd will soon see our Rotate */
    mysql_mutex_unlock(log_lock);
    if (likely((bool)ev))
    {
      ev->server_id= 0; // don't be ignored by slave SQL thread
      if (unlikely(rli->relay_log.append(ev)))
        mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                   ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
                   "failed to write a Rotate event"
                   " to the relay log, SHOW SLAVE STATUS may be"
                   " inaccurate");
      rli->relay_log.harvest_bytes_written(&rli->log_space_total);
      if (flush_master_info(mi, TRUE, TRUE))
        sql_print_error("Failed to flush master info file");
      delete ev;
    }
    else
      mi->report(ERROR_LEVEL, ER_SLAVE_CREATE_EVENT_FAILURE,
                 ER(ER_SLAVE_CREATE_EVENT_FAILURE),
                 "Rotate_event (out of memory?),"
                 " SHOW SLAVE STATUS may be inaccurate");
  }
  else
    mysql_mutex_unlock(log_lock);
  DBUG_VOID_RETURN;
}


int register_slave_on_master(MYSQL* mysql, Master_info *mi,
                             bool *suppress_warnings)
{
  uchar buf[1024], *pos= buf;
  uint report_host_len=0, report_user_len=0, report_password_len=0;
  DBUG_ENTER("register_slave_on_master");

  *suppress_warnings= FALSE;
  if (report_host)
    report_host_len= strlen(report_host);
  if (report_host_len > HOSTNAME_LENGTH)
  {
    sql_print_warning("The length of report_host is %d. "
                      "It is larger than the max length(%d), so this "
                      "slave cannot be registered to the master.",
                      report_host_len, HOSTNAME_LENGTH);
    DBUG_RETURN(0);
  }

  if (report_user)
    report_user_len= strlen(report_user);
  if (report_user_len > USERNAME_LENGTH)
  {
    sql_print_warning("The length of report_user is %d. "
                      "It is larger than the max length(%d), so this "
                      "slave cannot be registered to the master.",
                      report_user_len, USERNAME_LENGTH);
    DBUG_RETURN(0);
  }

  if (report_password)
    report_password_len= strlen(report_password);
  if (report_password_len > MAX_PASSWORD_LENGTH)
  {
    sql_print_warning("The length of report_password is %d. "
                      "It is larger than the max length(%d), so this "
                      "slave cannot be registered to the master.",
                      report_password_len, MAX_PASSWORD_LENGTH);
    DBUG_RETURN(0);
  }

  int4store(pos, server_id); pos+= 4;
  pos= net_store_data(pos, (uchar*) report_host, report_host_len);
  pos= net_store_data(pos, (uchar*) report_user, report_user_len);
  pos= net_store_data(pos, (uchar*) report_password, report_password_len);
  int2store(pos, (uint16) report_port); pos+= 2;
  /* 
    Fake rpl_recovery_rank, which was removed in BUG#13963,
    so that this server can register itself on old servers,
    see BUG#49259.
   */
  int4store(pos, /* rpl_recovery_rank */ 0);    pos+= 4;
  /* The master will fill in master_id */
  int4store(pos, 0);                    pos+= 4;

  if (simple_command(mysql, COM_REGISTER_SLAVE, buf, (size_t) (pos- buf), 0))
  {
    if (mysql_errno(mysql) == ER_NET_READ_INTERRUPTED)
    {
      *suppress_warnings= TRUE;                 // Suppress reconnect warning
    }
    else if (!check_io_slave_killed(mi->io_thd, mi, NULL))
    {
      char buf[256];
      my_snprintf(buf, sizeof(buf), "%s (Errno: %d)", mysql_error(mysql), 
                  mysql_errno(mysql));
      mi->report(ERROR_LEVEL, ER_SLAVE_MASTER_COM_FAILURE,
                 ER(ER_SLAVE_MASTER_COM_FAILURE), "COM_REGISTER_SLAVE", buf);
    }
    DBUG_RETURN(1);
  }
  DBUG_RETURN(0);
}


/**
  Execute a SHOW SLAVE STATUS statement.

  @param thd Pointer to THD object for the client thread executing the
  statement.

  @param mi Pointer to Master_info object for the IO thread.

  @retval FALSE success
  @retval TRUE failure
*/
bool show_master_info(THD* thd, Master_info* mi)
{
  // TODO: fix this for multi-master
  List<Item> field_list;
  Protocol *protocol= thd->protocol;
  DBUG_ENTER("show_master_info");

  field_list.push_back(new Item_empty_string("Slave_IO_State",
                                                     14));
  field_list.push_back(new Item_empty_string("Master_Host",
                                                     sizeof(mi->host)));
  field_list.push_back(new Item_empty_string("Master_User",
                                                     sizeof(mi->user)));
  field_list.push_back(new Item_return_int("Master_Port", 7,
                                           MYSQL_TYPE_LONG));
  field_list.push_back(new Item_return_int("Connect_Retry", 10,
                                           MYSQL_TYPE_LONG));
  field_list.push_back(new Item_empty_string("Master_Log_File",
                                             FN_REFLEN));
  field_list.push_back(new Item_return_int("Read_Master_Log_Pos", 10,
                                           MYSQL_TYPE_LONGLONG));
  field_list.push_back(new Item_empty_string("Relay_Log_File",
                                             FN_REFLEN));
  field_list.push_back(new Item_return_int("Relay_Log_Pos", 10,
                                           MYSQL_TYPE_LONGLONG));
  field_list.push_back(new Item_empty_string("Relay_Master_Log_File",
                                             FN_REFLEN));
  field_list.push_back(new Item_empty_string("Slave_IO_Running", 3));
  field_list.push_back(new Item_empty_string("Slave_SQL_Running", 3));
  field_list.push_back(new Item_empty_string("Replicate_Do_DB", 20));
  field_list.push_back(new Item_empty_string("Replicate_Ignore_DB", 20));
  field_list.push_back(new Item_empty_string("Replicate_Do_Table", 20));
  field_list.push_back(new Item_empty_string("Replicate_Ignore_Table", 23));
  field_list.push_back(new Item_empty_string("Replicate_Wild_Do_Table", 24));
  field_list.push_back(new Item_empty_string("Replicate_Wild_Ignore_Table",
                                             28));
  field_list.push_back(new Item_return_int("Last_Errno", 4, MYSQL_TYPE_LONG));
  field_list.push_back(new Item_empty_string("Last_Error", 20));
  field_list.push_back(new Item_return_int("Skip_Counter", 10,
                                           MYSQL_TYPE_LONG));
  field_list.push_back(new Item_return_int("Exec_Master_Log_Pos", 10,
                                           MYSQL_TYPE_LONGLONG));
  field_list.push_back(new Item_return_int("Relay_Log_Space", 10,
                                           MYSQL_TYPE_LONGLONG));
  field_list.push_back(new Item_empty_string("Until_Condition", 6));
  field_list.push_back(new Item_empty_string("Until_Log_File", FN_REFLEN));
  field_list.push_back(new Item_return_int("Until_Log_Pos", 10,
                                           MYSQL_TYPE_LONGLONG));
  field_list.push_back(new Item_empty_string("Master_SSL_Allowed", 7));
  field_list.push_back(new Item_empty_string("Master_SSL_CA_File",
                                             sizeof(mi->ssl_ca)));
  field_list.push_back(new Item_empty_string("Master_SSL_CA_Path",
                                             sizeof(mi->ssl_capath)));
  field_list.push_back(new Item_empty_string("Master_SSL_Cert",
                                             sizeof(mi->ssl_cert)));
  field_list.push_back(new Item_empty_string("Master_SSL_Cipher",
                                             sizeof(mi->ssl_cipher)));
  field_list.push_back(new Item_empty_string("Master_SSL_Key",
                                             sizeof(mi->ssl_key)));
  field_list.push_back(new Item_return_int("Seconds_Behind_Master", 10,
                                           MYSQL_TYPE_LONGLONG));
  field_list.push_back(new Item_empty_string("Master_SSL_Verify_Server_Cert",
                                             3));
  field_list.push_back(new Item_return_int("Last_IO_Errno", 4, MYSQL_TYPE_LONG));
  field_list.push_back(new Item_empty_string("Last_IO_Error", 20));
  field_list.push_back(new Item_return_int("Last_SQL_Errno", 4, MYSQL_TYPE_LONG));
  field_list.push_back(new Item_empty_string("Last_SQL_Error", 20));
  field_list.push_back(new Item_empty_string("Replicate_Ignore_Server_Ids",
                                             FN_REFLEN));
  field_list.push_back(new Item_return_int("Master_Server_Id", sizeof(ulong),
                                           MYSQL_TYPE_LONG));

  if (protocol->send_result_set_metadata(&field_list,
                            Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF))
    DBUG_RETURN(TRUE);

  if (mi->host[0])
  {
    DBUG_PRINT("info",("host is set: '%s'", mi->host));
    String *packet= &thd->packet;
    protocol->prepare_for_resend();

    /*
      slave_running can be accessed without run_lock but not other
      non-volotile members like mi->io_thd, which is guarded by the mutex.
    */
    mysql_mutex_lock(&mi->run_lock);
    protocol->store(mi->io_thd ? mi->io_thd->proc_info : "", &my_charset_bin);
    mysql_mutex_unlock(&mi->run_lock);

    mysql_mutex_lock(&mi->data_lock);
    mysql_mutex_lock(&mi->rli.data_lock);
    mysql_mutex_lock(&mi->err_lock);
    mysql_mutex_lock(&mi->rli.err_lock);
    protocol->store(mi->host, &my_charset_bin);
    protocol->store(mi->user, &my_charset_bin);
    protocol->store((uint32) mi->port);
    protocol->store((uint32) mi->connect_retry);
    protocol->store(mi->master_log_name, &my_charset_bin);
    protocol->store((ulonglong) mi->master_log_pos);
    protocol->store(mi->rli.group_relay_log_name +
                    dirname_length(mi->rli.group_relay_log_name),
                    &my_charset_bin);
    protocol->store((ulonglong) mi->rli.group_relay_log_pos);
    protocol->store(mi->rli.group_master_log_name, &my_charset_bin);
    protocol->store(mi->slave_running == MYSQL_SLAVE_RUN_CONNECT ?
                    "Yes" : (mi->slave_running == MYSQL_SLAVE_RUN_NOT_CONNECT ?
                             "Connecting" : "No"), &my_charset_bin);
    protocol->store(mi->rli.slave_running ? "Yes":"No", &my_charset_bin);
    protocol->store(rpl_filter->get_do_db());
    protocol->store(rpl_filter->get_ignore_db());

    char buf[256];
    String tmp(buf, sizeof(buf), &my_charset_bin);
    rpl_filter->get_do_table(&tmp);
    protocol->store(&tmp);
    rpl_filter->get_ignore_table(&tmp);
    protocol->store(&tmp);
    rpl_filter->get_wild_do_table(&tmp);
    protocol->store(&tmp);
    rpl_filter->get_wild_ignore_table(&tmp);
    protocol->store(&tmp);

    protocol->store(mi->rli.last_error().number);
    protocol->store(mi->rli.last_error().message, &my_charset_bin);
    protocol->store((uint32) mi->rli.slave_skip_counter);
    protocol->store((ulonglong) mi->rli.group_master_log_pos);
    protocol->store((ulonglong) mi->rli.log_space_total);

    protocol->store(
      mi->rli.until_condition==Relay_log_info::UNTIL_NONE ? "None":
        ( mi->rli.until_condition==Relay_log_info::UNTIL_MASTER_POS? "Master":
          "Relay"), &my_charset_bin);
    protocol->store(mi->rli.until_log_name, &my_charset_bin);
    protocol->store((ulonglong) mi->rli.until_log_pos);

#ifdef HAVE_OPENSSL
    protocol->store(mi->ssl? "Yes":"No", &my_charset_bin);
#else
    protocol->store(mi->ssl? "Ignored":"No", &my_charset_bin);
#endif
    protocol->store(mi->ssl_ca, &my_charset_bin);
    protocol->store(mi->ssl_capath, &my_charset_bin);
    protocol->store(mi->ssl_cert, &my_charset_bin);
    protocol->store(mi->ssl_cipher, &my_charset_bin);
    protocol->store(mi->ssl_key, &my_charset_bin);

    /*
      Seconds_Behind_Master: if SQL thread is running and I/O thread is
      connected, we can compute it otherwise show NULL (i.e. unknown).
    */
    if ((mi->slave_running == MYSQL_SLAVE_RUN_CONNECT) &&
        mi->rli.slave_running)
    {
      long time_diff= ((long)(time(0) - mi->rli.last_master_timestamp)
                       - mi->clock_diff_with_master);
      /*
        Apparently on some systems time_diff can be <0. Here are possible
        reasons related to MySQL:
        - the master is itself a slave of another master whose time is ahead.
        - somebody used an explicit SET TIMESTAMP on the master.
        Possible reason related to granularity-to-second of time functions
        (nothing to do with MySQL), which can explain a value of -1:
        assume the master's and slave's time are perfectly synchronized, and
        that at slave's connection time, when the master's timestamp is read,
        it is at the very end of second 1, and (a very short time later) when
        the slave's timestamp is read it is at the very beginning of second
        2. Then the recorded value for master is 1 and the recorded value for
        slave is 2. At SHOW SLAVE STATUS time, assume that the difference
        between timestamp of slave and rli->last_master_timestamp is 0
        (i.e. they are in the same second), then we get 0-(2-1)=-1 as a result.
        This confuses users, so we don't go below 0: hence the max().

        last_master_timestamp == 0 (an "impossible" timestamp 1970) is a
        special marker to say "consider we have caught up".
      */
      protocol->store((longlong)(mi->rli.last_master_timestamp ?
                                 max(0, time_diff) : 0));
    }
    else
    {
      protocol->store_null();
    }
    protocol->store(mi->ssl_verify_server_cert? "Yes":"No", &my_charset_bin);

    // Last_IO_Errno
    protocol->store(mi->last_error().number);
    // Last_IO_Error
    protocol->store(mi->last_error().message, &my_charset_bin);
    // Last_SQL_Errno
    protocol->store(mi->rli.last_error().number);
    // Last_SQL_Error
    protocol->store(mi->rli.last_error().message, &my_charset_bin);
    // Replicate_Ignore_Server_Ids
    {
      char buff[FN_REFLEN];
      ulong i, cur_len;
      for (i= 0, buff[0]= 0, cur_len= 0;
           i < mi->ignore_server_ids.elements; i++)
      {
        ulong s_id, slen;
        char sbuff[FN_REFLEN];
        get_dynamic(&mi->ignore_server_ids, (uchar*) &s_id, i);
        slen= sprintf(sbuff, (i==0? "%lu" : ", %lu"), s_id);
        if (cur_len + slen + 4 > FN_REFLEN)
        {
          /*
            break the loop whenever remained space could not fit
            ellipses on the next cycle
          */
          sprintf(buff + cur_len, "...");
          break;
        }
        cur_len += sprintf(buff + cur_len, "%s", sbuff);
      }
      protocol->store(buff, &my_charset_bin);
    }
    // Master_Server_id
    protocol->store((uint32) mi->master_id);

    mysql_mutex_unlock(&mi->rli.err_lock);
    mysql_mutex_unlock(&mi->err_lock);
    mysql_mutex_unlock(&mi->rli.data_lock);
    mysql_mutex_unlock(&mi->data_lock);

    if (my_net_write(&thd->net, (uchar*) thd->packet.ptr(), packet->length()))
      DBUG_RETURN(TRUE);
  }
  my_eof(thd);
  DBUG_RETURN(FALSE);
}


void set_slave_thread_options(THD* thd)
{
  DBUG_ENTER("set_slave_thread_options");
  /*
     It's nonsense to constrain the slave threads with max_join_size; if a
     query succeeded on master, we HAVE to execute it. So set
     OPTION_BIG_SELECTS. Setting max_join_size to HA_POS_ERROR is not enough
     (and it's not needed if we have OPTION_BIG_SELECTS) because an INSERT
     SELECT examining more than 4 billion rows would still fail (yes, because
     when max_join_size is 4G, OPTION_BIG_SELECTS is automatically set, but
     only for client threads.
  */
  ulonglong options= thd->variables.option_bits | OPTION_BIG_SELECTS;
  if (opt_log_slave_updates)
    options|= OPTION_BIN_LOG;
  else
    options&= ~OPTION_BIN_LOG;
  thd->variables.option_bits= options;
  thd->variables.completion_type= 0;
  DBUG_VOID_RETURN;
}

void set_slave_thread_default_charset(THD* thd, Relay_log_info const *rli)
{
  DBUG_ENTER("set_slave_thread_default_charset");

  thd->variables.character_set_client=
    global_system_variables.character_set_client;
  thd->variables.collation_connection=
    global_system_variables.collation_connection;
  thd->variables.collation_server=
    global_system_variables.collation_server;
  thd->update_charset();

  /*
    We use a const cast here since the conceptual (and externally
    visible) behavior of the function is to set the default charset of
    the thread.  That the cache has to be invalidated is a secondary
    effect.
   */
  const_cast<Relay_log_info*>(rli)->cached_charset_invalidate();
  DBUG_VOID_RETURN;
}

/*
  init_slave_thread()
*/

static int init_slave_thread(THD* thd, SLAVE_THD_TYPE thd_type)
{
  DBUG_ENTER("init_slave_thread");
#if !defined(DBUG_OFF)
  int simulate_error= 0;
#endif
  thd->system_thread = (thd_type == SLAVE_THD_SQL) ?
    SYSTEM_THREAD_SLAVE_SQL : SYSTEM_THREAD_SLAVE_IO;
  thd->security_ctx->skip_grants();
  my_net_init(&thd->net, 0);
/*
  Adding MAX_LOG_EVENT_HEADER_LEN to the max_allowed_packet on all
  slave threads, since a replication event can become this much larger
  than the corresponding packet (query) sent from client to master.
*/
  thd->variables.max_allowed_packet= global_system_variables.max_allowed_packet
    + MAX_LOG_EVENT_HEADER;  /* note, incr over the global not session var */
  thd->slave_thread = 1;
  thd->enable_slow_log= opt_log_slow_slave_statements;
  set_slave_thread_options(thd);
  thd->client_capabilities = CLIENT_LOCAL_FILES;
  mysql_mutex_lock(&LOCK_thread_count);
  thd->thread_id= thd->variables.pseudo_thread_id= thread_id++;
  mysql_mutex_unlock(&LOCK_thread_count);

  DBUG_EXECUTE_IF("simulate_io_slave_error_on_init",
                  simulate_error|= (1 << SLAVE_THD_IO););
  DBUG_EXECUTE_IF("simulate_sql_slave_error_on_init",
                  simulate_error|= (1 << SLAVE_THD_SQL););
#if !defined(DBUG_OFF)
  if (init_thr_lock() || thd->store_globals() || simulate_error & (1<< thd_type))
#else
  if (init_thr_lock() || thd->store_globals())
#endif
  {
    thd->cleanup();
    DBUG_RETURN(-1);
  }

  if (thd_type == SLAVE_THD_SQL)
    thd_proc_info(thd, "Waiting for the next event in relay log");
  else
    thd_proc_info(thd, "Waiting for master update");
  thd->set_time();
  /* Do not use user-supplied timeout value for system threads. */
  thd->variables.lock_wait_timeout= LONG_TIMEOUT;
  DBUG_RETURN(0);
}


static int safe_sleep(THD* thd, int sec, CHECK_KILLED_FUNC thread_killed,
                      void* thread_killed_arg)
{
  int nap_time;
  thr_alarm_t alarmed;
  DBUG_ENTER("safe_sleep");

  thr_alarm_init(&alarmed);
  time_t start_time= my_time(0);
  time_t end_time= start_time+sec;

  while ((nap_time= (int) (end_time - start_time)) > 0)
  {
    ALARM alarm_buff;
    /*
      The only reason we are asking for alarm is so that
      we will be woken up in case of murder, so if we do not get killed,
      set the alarm so it goes off after we wake up naturally
    */
    thr_alarm(&alarmed, 2 * nap_time, &alarm_buff);
    sleep(nap_time);
    thr_end_alarm(&alarmed);

    if ((*thread_killed)(thd,thread_killed_arg))
      DBUG_RETURN(1);
    start_time= my_time(0);
  }
  DBUG_RETURN(0);
}


static int request_dump(THD *thd, MYSQL* mysql, Master_info* mi,
			bool *suppress_warnings)
{
  uchar buf[FN_REFLEN + 10];
  int len;
  ushort binlog_flags = 0; // for now
  char* logname = mi->master_log_name;
  DBUG_ENTER("request_dump");
  
  *suppress_warnings= FALSE;

  if (RUN_HOOK(binlog_relay_io,
               before_request_transmit,
               (thd, mi, binlog_flags)))
    DBUG_RETURN(1);
  
  // TODO if big log files: Change next to int8store()
  int4store(buf, (ulong) mi->master_log_pos);
  int2store(buf + 4, binlog_flags);
  int4store(buf + 6, server_id);
  len = (uint) strlen(logname);
  memcpy(buf + 10, logname,len);
  if (simple_command(mysql, COM_BINLOG_DUMP, buf, len + 10, 1))
  {
    /*
      Something went wrong, so we will just reconnect and retry later
      in the future, we should do a better error analysis, but for
      now we just fill up the error log :-)
    */
    if (mysql_errno(mysql) == ER_NET_READ_INTERRUPTED)
      *suppress_warnings= TRUE;                 // Suppress reconnect warning
    else
      sql_print_error("Error on COM_BINLOG_DUMP: %d  %s, will retry in %d secs",
                      mysql_errno(mysql), mysql_error(mysql),
                      mi->connect_retry);
    DBUG_RETURN(1);
  }

  DBUG_RETURN(0);
}


/*
  Read one event from the master

  SYNOPSIS
    read_event()
    mysql               MySQL connection
    mi                  Master connection information
    suppress_warnings   TRUE when a normal net read timeout has caused us to
                        try a reconnect.  We do not want to print anything to
                        the error log in this case because this a anormal
                        event in an idle server.

    RETURN VALUES
    'packet_error'      Error
    number              Length of packet
*/

static ulong read_event(MYSQL* mysql, Master_info *mi, bool* suppress_warnings)
{
  ulong len;
  DBUG_ENTER("read_event");

  *suppress_warnings= FALSE;
  /*
    my_real_read() will time us out
    We check if we were told to die, and if not, try reading again
  */
#ifndef DBUG_OFF
  if (disconnect_slave_event_count && !(mi->events_till_disconnect--))
    DBUG_RETURN(packet_error);
#endif

  len = cli_safe_read(mysql);
  if (len == packet_error || (long) len < 1)
  {
    if (mysql_errno(mysql) == ER_NET_READ_INTERRUPTED)
    {
      /*
        We are trying a normal reconnect after a read timeout;
        we suppress prints to .err file as long as the reconnect
        happens without problems
      */
      *suppress_warnings= TRUE;
    }
    else
      sql_print_error("Error reading packet from server: %s ( server_errno=%d)",
                      mysql_error(mysql), mysql_errno(mysql));
    DBUG_RETURN(packet_error);
  }

  /* Check if eof packet */
  if (len < 8 && mysql->net.read_pos[0] == 254)
  {
    sql_print_information("Slave: received end packet from server, apparent "
                          "master shutdown: %s",
                     mysql_error(mysql));
     DBUG_RETURN(packet_error);
  }

  DBUG_PRINT("exit", ("len: %lu  net->read_pos[4]: %d",
                      len, mysql->net.read_pos[4]));
  DBUG_RETURN(len - 1);
}

/*
  Check if the current error is of temporary nature of not.
  Some errors are temporary in nature, such as
  ER_LOCK_DEADLOCK and ER_LOCK_WAIT_TIMEOUT.  Ndb also signals
  that the error is temporary by pushing a warning with the error code
  ER_GET_TEMPORARY_ERRMSG, if the originating error is temporary.
*/
static int has_temporary_error(THD *thd)
{
  DBUG_ENTER("has_temporary_error");

  DBUG_EXECUTE_IF("all_errors_are_temporary_errors",
                  if (thd->stmt_da->is_error())
                  {
                    thd->clear_error();
                    my_error(ER_LOCK_DEADLOCK, MYF(0));
                  });

  /*
    If there is no message in THD, we can't say if it's a temporary
    error or not. This is currently the case for Incident_log_event,
    which sets no message. Return FALSE.
  */
  if (!thd->is_error())
    DBUG_RETURN(0);

  /*
    Temporary error codes:
    currently, InnoDB deadlock detected by InnoDB or lock
    wait timeout (innodb_lock_wait_timeout exceeded
  */
  if (thd->stmt_da->sql_errno() == ER_LOCK_DEADLOCK ||
      thd->stmt_da->sql_errno() == ER_LOCK_WAIT_TIMEOUT)
    DBUG_RETURN(1);

#ifdef HAVE_NDB_BINLOG
  /*
    currently temporary error set in ndbcluster
  */
  List_iterator_fast<MYSQL_ERROR> it(thd->warning_info->warn_list());
  MYSQL_ERROR *err;
  while ((err= it++))
  {
    DBUG_PRINT("info", ("has condition %d %s", err->get_sql_errno(),
                        err->get_message_text()));
    switch (err->get_sql_errno())
    {
    case ER_GET_TEMPORARY_ERRMSG:
      DBUG_RETURN(1);
    default:
      break;
    }
  }
#endif
  DBUG_RETURN(0);
}


/**
  Applies the given event and advances the relay log position.

  In essence, this function does:

  @code
    ev->apply_event(rli);
    ev->update_pos(rli);
  @endcode

  But it also does some maintainance, such as skipping events if
  needed and reporting errors.

  If the @c skip flag is set, then it is tested whether the event
  should be skipped, by looking at the slave_skip_counter and the
  server id.  The skip flag should be set when calling this from a
  replication thread but not set when executing an explicit BINLOG
  statement.

  @retval 0 OK.

  @retval 1 Error calling ev->apply_event().

  @retval 2 No error calling ev->apply_event(), but error calling
  ev->update_pos().
*/
int apply_event_and_update_pos(Log_event* ev, THD* thd, Relay_log_info* rli)
{
  int exec_res= 0;

  DBUG_ENTER("apply_event_and_update_pos");

  DBUG_PRINT("exec_event",("%s(type_code: %d; server_id: %d)",
                           ev->get_type_str(), ev->get_type_code(),
                           ev->server_id));
  DBUG_PRINT("info", ("thd->options: %s%s; rli->last_event_start_time: %lu",
                      FLAGSTR(thd->variables.option_bits, OPTION_NOT_AUTOCOMMIT),
                      FLAGSTR(thd->variables.option_bits, OPTION_BEGIN),
                      (ulong) rli->last_event_start_time));

  /*
    Execute the event to change the database and update the binary
    log coordinates, but first we set some data that is needed for
    the thread.

    The event will be executed unless it is supposed to be skipped.

    Queries originating from this server must be skipped.  Low-level
    events (Format_description_log_event, Rotate_log_event,
    Stop_log_event) from this server must also be skipped. But for
    those we don't want to modify 'group_master_log_pos', because
    these events did not exist on the master.
    Format_description_log_event is not completely skipped.

    Skip queries specified by the user in 'slave_skip_counter'.  We
    can't however skip events that has something to do with the log
    files themselves.

    Filtering on own server id is extremely important, to ignore
    execution of events created by the creation/rotation of the relay
    log (remember that now the relay log starts with its Format_desc,
    has a Rotate etc).
  */

  thd->server_id = ev->server_id; // use the original server id for logging
  thd->set_time();                            // time the query
  thd->lex->current_select= 0;
  if (!ev->when)
    ev->when= my_time(0);
  ev->thd = thd; // because up to this point, ev->thd == 0

  int reason= ev->shall_skip(rli);
  if (reason == Log_event::EVENT_SKIP_COUNT)
    sql_slave_skip_counter= --rli->slave_skip_counter;
  mysql_mutex_unlock(&rli->data_lock);
  if (reason == Log_event::EVENT_SKIP_NOT)
    exec_res= ev->apply_event(rli);

#ifndef DBUG_OFF
  /*
    This only prints information to the debug trace.

    TODO: Print an informational message to the error log?
  */
  static const char *const explain[] = {
    // EVENT_SKIP_NOT,
    "not skipped",
    // EVENT_SKIP_IGNORE,
    "skipped because event should be ignored",
    // EVENT_SKIP_COUNT
    "skipped because event skip counter was non-zero"
  };
  DBUG_PRINT("info", ("OPTION_BEGIN: %d; IN_STMT: %d",
                      test(thd->variables.option_bits & OPTION_BEGIN),
                      rli->get_flag(Relay_log_info::IN_STMT)));
  DBUG_PRINT("skip_event", ("%s event was %s",
                            ev->get_type_str(), explain[reason]));
#endif

  DBUG_PRINT("info", ("apply_event error = %d", exec_res));
  if (exec_res == 0)
  {
    int error= ev->update_pos(rli);
#ifdef HAVE_purify
    if (!rli->is_fake)
#endif
    {
#ifndef DBUG_OFF
      char buf[22];
#endif
      DBUG_PRINT("info", ("update_pos error = %d", error));
      DBUG_PRINT("info", ("group %s %s",
                          llstr(rli->group_relay_log_pos, buf),
                          rli->group_relay_log_name));
      DBUG_PRINT("info", ("event %s %s",
                          llstr(rli->event_relay_log_pos, buf),
                          rli->event_relay_log_name));
    }
    /*
      The update should not fail, so print an error message and
      return an error code.

      TODO: Replace this with a decent error message when merged
      with BUG#24954 (which adds several new error message).
    */
    if (error)
    {
      char buf[22];
      rli->report(ERROR_LEVEL, ER_UNKNOWN_ERROR,
                  "It was not possible to update the positions"
                  " of the relay log information: the slave may"
                  " be in an inconsistent state."
                  " Stopped in %s position %s",
                  rli->group_relay_log_name,
                  llstr(rli->group_relay_log_pos, buf));
      DBUG_RETURN(2);
    }
  }

  DBUG_RETURN(exec_res ? 1 : 0);
}


/**
  Top-level function for executing the next event from the relay log.

  This function reads the event from the relay log, executes it, and
  advances the relay log position.  It also handles errors, etc.

  This function may fail to apply the event for the following reasons:

   - The position specfied by the UNTIL condition of the START SLAVE
     command is reached.

   - It was not possible to read the event from the log.

   - The slave is killed.

   - An error occurred when applying the event, and the event has been
     tried slave_trans_retries times.  If the event has been retried
     fewer times, 0 is returned.

   - init_master_info or init_relay_log_pos failed. (These are called
     if a failure occurs when applying the event.)

   - An error occurred when updating the binlog position.

  @retval 0 The event was applied.

  @retval 1 The event was not applied.
*/
static int exec_relay_log_event(THD* thd, Relay_log_info* rli)
{
  DBUG_ENTER("exec_relay_log_event");

  /*
     We acquire this mutex since we need it for all operations except
     event execution. But we will release it in places where we will
     wait for something for example inside of next_event().
   */
  mysql_mutex_lock(&rli->data_lock);

  Log_event * ev = next_event(rli);

  DBUG_ASSERT(rli->sql_thd==thd);

  if (sql_slave_killed(thd,rli))
  {
    mysql_mutex_unlock(&rli->data_lock);
    delete ev;
    DBUG_RETURN(1);
  }
  if (ev)
  {
    int exec_res;

    /*
      This tests if the position of the beginning of the current event
      hits the UNTIL barrier.
    */
    if (rli->until_condition != Relay_log_info::UNTIL_NONE &&
        rli->is_until_satisfied(thd, ev))
    {
      char buf[22];
      sql_print_information("Slave SQL thread stopped because it reached its"
                            " UNTIL position %s", llstr(rli->until_pos(), buf));
      /*
        Setting abort_slave flag because we do not want additional message about
        error in query execution to be printed.
      */
      rli->abort_slave= 1;
      mysql_mutex_unlock(&rli->data_lock);
      delete ev;
      DBUG_RETURN(1);
    }

    { /**
         The following failure injecion works in cooperation with tests 
         setting @@global.debug= 'd,incomplete_group_in_relay_log'.
         Xid or Commit events are not executed to force the slave sql
         read hanging if the realy log does not have any more events.
      */
      DBUG_EXECUTE_IF("incomplete_group_in_relay_log",
                      if ((ev->get_type_code() == XID_EVENT) ||
                          ((ev->get_type_code() == QUERY_EVENT) &&
                           strcmp("COMMIT", ((Query_log_event *) ev)->query) == 0))
                      {
                        DBUG_ASSERT(thd->transaction.all.modified_non_trans_table);
                        rli->abort_slave= 1;
                        mysql_mutex_unlock(&rli->data_lock);
                        delete ev;
                        rli->inc_event_relay_log_pos();
                        DBUG_RETURN(0);
                      };);
    }

    exec_res= apply_event_and_update_pos(ev, thd, rli);

    /*
      Format_description_log_event should not be deleted because it will be
      used to read info about the relay log's format; it will be deleted when
      the SQL thread does not need it, i.e. when this thread terminates.
    */
    if (ev->get_type_code() != FORMAT_DESCRIPTION_EVENT)
    {
      DBUG_PRINT("info", ("Deleting the event after it has been executed"));
      delete ev;
    }

    /*
      update_log_pos failed: this should not happen, so we don't
      retry.
    */
    if (exec_res == 2)
      DBUG_RETURN(1);

    if (slave_trans_retries)
    {
      int UNINIT_VAR(temp_err);
      if (exec_res && (temp_err= has_temporary_error(thd)))
      {
        const char *errmsg;
        /*
          We were in a transaction which has been rolled back because of a
          temporary error;
          let's seek back to BEGIN log event and retry it all again.
	  Note, if lock wait timeout (innodb_lock_wait_timeout exceeded)
	  there is no rollback since 5.0.13 (ref: manual).
          We have to not only seek but also
          a) init_master_info(), to seek back to hot relay log's start for later
          (for when we will come back to this hot log after re-processing the
          possibly existing old logs where BEGIN is: check_binlog_magic() will
          then need the cache to be at position 0 (see comments at beginning of
          init_master_info()).
          b) init_relay_log_pos(), because the BEGIN may be an older relay log.
        */
        if (rli->trans_retries < slave_trans_retries)
        {
          if (init_master_info(rli->mi, 0, 0, 0, SLAVE_SQL))
            sql_print_error("Failed to initialize the master info structure");
          else if (init_relay_log_pos(rli,
                                      rli->group_relay_log_name,
                                      rli->group_relay_log_pos,
                                      1, &errmsg, 1))
            sql_print_error("Error initializing relay log position: %s",
                            errmsg);
          else
          {
            exec_res= 0;
            rli->cleanup_context(thd, 1);
            /* chance for concurrent connection to get more locks */
            safe_sleep(thd, min(rli->trans_retries, MAX_SLAVE_RETRY_PAUSE),
                       (CHECK_KILLED_FUNC)sql_slave_killed, (void*)rli);
            mysql_mutex_lock(&rli->data_lock); // because of SHOW STATUS
            rli->trans_retries++;
            rli->retried_trans++;
            mysql_mutex_unlock(&rli->data_lock);
            DBUG_PRINT("info", ("Slave retries transaction "
                                "rli->trans_retries: %lu", rli->trans_retries));
          }
        }
        else
          sql_print_error("Slave SQL thread retried transaction %lu time(s) "
                          "in vain, giving up. Consider raising the value of "
                          "the slave_transaction_retries variable.",
                          slave_trans_retries);
      }
      else if ((exec_res && !temp_err) ||
               (opt_using_transactions &&
                rli->group_relay_log_pos == rli->event_relay_log_pos))
      {
        /*
          Only reset the retry counter if the entire group succeeded
          or failed with a non-transient error.  On a successful
          event, the execution will proceed as usual; in the case of a
          non-transient error, the slave will stop with an error.
         */
        rli->trans_retries= 0; // restart from fresh
        DBUG_PRINT("info", ("Resetting retry counter, rli->trans_retries: %lu",
                            rli->trans_retries));
      }
    }
    DBUG_RETURN(exec_res);
  }
  mysql_mutex_unlock(&rli->data_lock);
  rli->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_READ_FAILURE,
              ER(ER_SLAVE_RELAY_LOG_READ_FAILURE), "\
Could not parse relay log event entry. The possible reasons are: the master's \
binary log is corrupted (you can check this by running 'mysqlbinlog' on the \
binary log), the slave's relay log is corrupted (you can check this by running \
'mysqlbinlog' on the relay log), a network problem, or a bug in the master's \
or slave's MySQL code. If you want to check the master's binary log or slave's \
relay log, you will be able to know their names by issuing 'SHOW SLAVE STATUS' \
on this slave.\
");
  DBUG_RETURN(1);
}


static bool check_io_slave_killed(THD *thd, Master_info *mi, const char *info)
{
  if (io_slave_killed(thd, mi))
  {
    if (info && global_system_variables.log_warnings)
      sql_print_information("%s", info);
    return TRUE;
  }
  return FALSE;
}

/**
  @brief Try to reconnect slave IO thread.

  @details Terminates current connection to master, sleeps for
  @c mi->connect_retry msecs and initiates new connection with
  @c safe_reconnect(). Variable pointed by @c retry_count is increased -
  if it exceeds @c master_retry_count then connection is not re-established
  and function signals error.
  Unless @c suppres_warnings is TRUE, a warning is put in the server error log
  when reconnecting. The warning message and messages used to report errors
  are taken from @c messages array. In case @c master_retry_count is exceeded,
  no messages are added to the log.

  @param[in]     thd                 Thread context.
  @param[in]     mysql               MySQL connection.
  @param[in]     mi                  Master connection information.
  @param[in,out] retry_count         Number of attempts to reconnect.
  @param[in]     suppress_warnings   TRUE when a normal net read timeout 
                                     has caused to reconnecting.
  @param[in]     messages            Messages to print/log, see 
                                     reconnect_messages[] array.

  @retval        0                   OK.
  @retval        1                   There was an error.
*/

static int try_to_reconnect(THD *thd, MYSQL *mysql, Master_info *mi,
                            uint *retry_count, bool suppress_warnings,
                            const char *messages[SLAVE_RECON_MSG_MAX])
{
  mi->slave_running= MYSQL_SLAVE_RUN_NOT_CONNECT;
  thd->proc_info= messages[SLAVE_RECON_MSG_WAIT];
#ifdef SIGNAL_WITH_VIO_CLOSE  
  thd->clear_active_vio();
#endif
  end_server(mysql);
  if ((*retry_count)++)
  {
    if (*retry_count > master_retry_count)
      return 1;                             // Don't retry forever
    safe_sleep(thd, mi->connect_retry, (CHECK_KILLED_FUNC) io_slave_killed,
               (void *) mi);
  }
  if (check_io_slave_killed(thd, mi, messages[SLAVE_RECON_MSG_KILLED_WAITING]))
    return 1;
  thd->proc_info = messages[SLAVE_RECON_MSG_AFTER];
  if (!suppress_warnings) 
  {
    char buf[256], llbuff[22];
    my_snprintf(buf, sizeof(buf), messages[SLAVE_RECON_MSG_FAILED], 
                IO_RPL_LOG_NAME, llstr(mi->master_log_pos, llbuff));
    /* 
      Raise a warining during registering on master/requesting dump.
      Log a message reading event.
    */
    if (messages[SLAVE_RECON_MSG_COMMAND][0])
    {
      mi->report(WARNING_LEVEL, ER_SLAVE_MASTER_COM_FAILURE,
                 ER(ER_SLAVE_MASTER_COM_FAILURE), 
                 messages[SLAVE_RECON_MSG_COMMAND], buf);
    }
    else
    {
      sql_print_information("%s", buf);
    }
  }
  if (safe_reconnect(thd, mysql, mi, 1) || io_slave_killed(thd, mi))
  {
    if (global_system_variables.log_warnings)
      sql_print_information("%s", messages[SLAVE_RECON_MSG_KILLED_AFTER]);
    return 1;
  }
  return 0;
}


/**
  Slave IO thread entry point.

  @param arg Pointer to Master_info struct that holds information for
  the IO thread.

  @return Always 0.
*/
pthread_handler_t handle_slave_io(void *arg)
{
  THD *thd; // needs to be first for thread_stack
  MYSQL *mysql;
  Master_info *mi = (Master_info*)arg;
  Relay_log_info *rli= &mi->rli;
  char llbuff[22];
  uint retry_count;
  bool suppress_warnings;
  int ret;
#ifndef DBUG_OFF
  uint retry_count_reg= 0, retry_count_dump= 0, retry_count_event= 0;
#endif
  // needs to call my_thread_init(), otherwise we get a coredump in DBUG_ stuff
  my_thread_init();
  DBUG_ENTER("handle_slave_io");

  DBUG_ASSERT(mi->inited);
  mysql= NULL ;
  retry_count= 0;

  mysql_mutex_lock(&mi->run_lock);
  /* Inform waiting threads that slave has started */
  mi->slave_run_id++;

#ifndef DBUG_OFF
  mi->events_till_disconnect = disconnect_slave_event_count;
#endif

  thd= new THD; // note that contructor of THD uses DBUG_ !
  THD_CHECK_SENTRY(thd);
  mi->io_thd = thd;

  pthread_detach_this_thread();
  thd->thread_stack= (char*) &thd; // remember where our stack is
  mi->clear_error();
  if (init_slave_thread(thd, SLAVE_THD_IO))
  {
    mysql_cond_broadcast(&mi->start_cond);
    mysql_mutex_unlock(&mi->run_lock);
    sql_print_error("Failed during slave I/O thread initialization");
    goto err;
  }
  mysql_mutex_lock(&LOCK_thread_count);
  threads.append(thd);
  mysql_mutex_unlock(&LOCK_thread_count);
  mi->slave_running = 1;
  mi->abort_slave = 0;
  mysql_mutex_unlock(&mi->run_lock);
  mysql_cond_broadcast(&mi->start_cond);

  DBUG_PRINT("master_info",("log_file_name: '%s'  position: %s",
                            mi->master_log_name,
                            llstr(mi->master_log_pos,llbuff)));

  /* This must be called before run any binlog_relay_io hooks */
  my_pthread_setspecific_ptr(RPL_MASTER_INFO, mi);

  if (RUN_HOOK(binlog_relay_io, thread_start, (thd, mi)))
  {
    mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
               ER(ER_SLAVE_FATAL_ERROR), "Failed to run 'thread_start' hook");
    goto err;
  }

  if (!(mi->mysql = mysql = mysql_init(NULL)))
  {
    mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
               ER(ER_SLAVE_FATAL_ERROR), "error in mysql_init()");
    goto err;
  }

  thd_proc_info(thd, "Connecting to master");
  // we can get killed during safe_connect
  if (!safe_connect(thd, mysql, mi))
  {
    sql_print_information("Slave I/O thread: connected to master '%s@%s:%d',"
                          "replication started in log '%s' at position %s",
                          mi->user, mi->host, mi->port,
			  IO_RPL_LOG_NAME,
			  llstr(mi->master_log_pos,llbuff));
  /*
    Adding MAX_LOG_EVENT_HEADER_LEN to the max_packet_size on the I/O
    thread, since a replication event can become this much larger than
    the corresponding packet (query) sent from client to master.
  */
    mysql->net.max_packet_size= thd->net.max_packet_size+= MAX_LOG_EVENT_HEADER;
  }
  else
  {
    sql_print_information("Slave I/O thread killed while connecting to master");
    goto err;
  }

connected:

    DBUG_EXECUTE_IF("dbug.before_get_running_status_yes",
                    {
                      const char act[]=
                        "now "
                        "wait_for signal.io_thread_let_running";
                      DBUG_ASSERT(opt_debug_sync_timeout > 0);
                      DBUG_ASSERT(!debug_sync_set_action(thd, 
                                                         STRING_WITH_LEN(act)));
                    };);

  // TODO: the assignment below should be under mutex (5.0)
  mi->slave_running= MYSQL_SLAVE_RUN_CONNECT;
  thd->slave_net = &mysql->net;
  thd_proc_info(thd, "Checking master version");
  ret= get_master_version_and_clock(mysql, mi);
  if (ret == 1)
    /* Fatal error */
    goto err;

  if (ret == 2) 
  { 
    if (check_io_slave_killed(mi->io_thd, mi, "Slave I/O thread killed"
                              "while calling get_master_version_and_clock(...)"))
      goto err;
    suppress_warnings= FALSE;
    /* Try to reconnect because the error was caused by a transient network problem */
    if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
                             reconnect_messages[SLAVE_RECON_ACT_REG]))
      goto err;
    goto connected;
  } 

  if (mi->rli.relay_log.description_event_for_queue->binlog_version > 1)
  {
    /*
      Register ourselves with the master.
    */
    thd_proc_info(thd, "Registering slave on master");
    if (register_slave_on_master(mysql, mi, &suppress_warnings))
    {
      if (!check_io_slave_killed(thd, mi, "Slave I/O thread killed "
                                "while registering slave on master"))
      {
        sql_print_error("Slave I/O thread couldn't register on master");
        if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
                             reconnect_messages[SLAVE_RECON_ACT_REG]))
          goto err;
      }
      else
        goto err;
      goto connected;
    }
    DBUG_EXECUTE_IF("FORCE_SLAVE_TO_RECONNECT_REG", 
      if (!retry_count_reg)
      {
        retry_count_reg++;
        sql_print_information("Forcing to reconnect slave I/O thread");
        if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
                             reconnect_messages[SLAVE_RECON_ACT_REG]))
          goto err;
        goto connected;
      });
  }

  DBUG_PRINT("info",("Starting reading binary log from master"));
  while (!io_slave_killed(thd,mi))
  {
    thd_proc_info(thd, "Requesting binlog dump");
    if (request_dump(thd, mysql, mi, &suppress_warnings))
    {
      sql_print_error("Failed on request_dump()");
      if (check_io_slave_killed(thd, mi, "Slave I/O thread killed while \
requesting master dump") ||
          try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
                           reconnect_messages[SLAVE_RECON_ACT_DUMP]))
        goto err;
      goto connected;
    }
    DBUG_EXECUTE_IF("FORCE_SLAVE_TO_RECONNECT_DUMP", 
      if (!retry_count_dump)
      {
        retry_count_dump++;
        sql_print_information("Forcing to reconnect slave I/O thread");
        if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
                             reconnect_messages[SLAVE_RECON_ACT_DUMP]))
          goto err;
        goto connected;
      });
    const char *event_buf;

    DBUG_ASSERT(mi->last_error().number == 0);
    while (!io_slave_killed(thd,mi))
    {
      ulong event_len;
      /*
         We say "waiting" because read_event() will wait if there's nothing to
         read. But if there's something to read, it will not wait. The
         important thing is to not confuse users by saying "reading" whereas
         we're in fact receiving nothing.
      */
      thd_proc_info(thd, "Waiting for master to send event");
      event_len= read_event(mysql, mi, &suppress_warnings);
      if (check_io_slave_killed(thd, mi, "Slave I/O thread killed while \
reading event"))
        goto err;
      DBUG_EXECUTE_IF("FORCE_SLAVE_TO_RECONNECT_EVENT",
        if (!retry_count_event)
        {
          retry_count_event++;
          sql_print_information("Forcing to reconnect slave I/O thread");
          if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
                               reconnect_messages[SLAVE_RECON_ACT_EVENT]))
            goto err;
          goto connected;
        });

      if (event_len == packet_error)
      {
        uint mysql_error_number= mysql_errno(mysql);
        switch (mysql_error_number) {
        case CR_NET_PACKET_TOO_LARGE:
          sql_print_error("\
Log entry on master is longer than max_allowed_packet (%ld) on \
slave. If the entry is correct, restart the server with a higher value of \
max_allowed_packet",
                          thd->variables.max_allowed_packet);
          mi->report(ERROR_LEVEL, ER_NET_PACKET_TOO_LARGE,
                     "%s", ER(ER_NET_PACKET_TOO_LARGE));
          goto err;
        case ER_MASTER_FATAL_ERROR_READING_BINLOG:
          mi->report(ERROR_LEVEL, ER_MASTER_FATAL_ERROR_READING_BINLOG,
                     ER(ER_MASTER_FATAL_ERROR_READING_BINLOG),
                     mysql_error_number, mysql_error(mysql));
          goto err;
        case ER_OUT_OF_RESOURCES:
          sql_print_error("\
Stopping slave I/O thread due to out-of-memory error from master");
          mi->report(ERROR_LEVEL, ER_OUT_OF_RESOURCES,
                     "%s", ER(ER_OUT_OF_RESOURCES));
          goto err;
        }
        if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
                             reconnect_messages[SLAVE_RECON_ACT_EVENT]))
          goto err;
        goto connected;
      } // if (event_len == packet_error)

      retry_count=0;                    // ok event, reset retry counter
      thd_proc_info(thd, "Queueing master event to the relay log");
      event_buf= (const char*)mysql->net.read_pos + 1;
      if (RUN_HOOK(binlog_relay_io, after_read_event,
                   (thd, mi,(const char*)mysql->net.read_pos + 1,
                    event_len, &event_buf, &event_len)))
      {
        mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
                   ER(ER_SLAVE_FATAL_ERROR),
                   "Failed to run 'after_read_event' hook");
        goto err;
      }

      /* XXX: 'synced' should be updated by queue_event to indicate
         whether event has been synced to disk */
      bool synced= 0;
      if (queue_event(mi, event_buf, event_len))
      {
        mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                   ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
                   "could not queue event from master");
        goto err;
      }

      if (RUN_HOOK(binlog_relay_io, after_queue_event,
                   (thd, mi, event_buf, event_len, synced)))
      {
        mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
                   ER(ER_SLAVE_FATAL_ERROR),
                   "Failed to run 'after_queue_event' hook");
        goto err;
      }

      if (flush_master_info(mi, TRUE, TRUE))
      {
        sql_print_error("Failed to flush master info file");
        goto err;
      }
      /*
        See if the relay logs take too much space.
        We don't lock mi->rli.log_space_lock here; this dirty read saves time
        and does not introduce any problem:
        - if mi->rli.ignore_log_space_limit is 1 but becomes 0 just after (so
        the clean value is 0), then we are reading only one more event as we
        should, and we'll block only at the next event. No big deal.
        - if mi->rli.ignore_log_space_limit is 0 but becomes 1 just after (so
        the clean value is 1), then we are going into wait_for_relay_log_space()
        for no reason, but this function will do a clean read, notice the clean
        value and exit immediately.
      */
#ifndef DBUG_OFF
      {
        char llbuf1[22], llbuf2[22];
        DBUG_PRINT("info", ("log_space_limit=%s log_space_total=%s \
ignore_log_space_limit=%d",
                            llstr(rli->log_space_limit,llbuf1),
                            llstr(rli->log_space_total,llbuf2),
                            (int) rli->ignore_log_space_limit));
      }
#endif

      if (rli->log_space_limit && rli->log_space_limit <
          rli->log_space_total &&
          !rli->ignore_log_space_limit)
        if (wait_for_relay_log_space(rli))
        {
          sql_print_error("Slave I/O thread aborted while waiting for relay \
log space");
          goto err;
        }
    }
  }

  // error = 0;
err:
  // print the current replication position
  sql_print_information("Slave I/O thread exiting, read up to log '%s', position %s",
                  IO_RPL_LOG_NAME, llstr(mi->master_log_pos,llbuff));
  RUN_HOOK(binlog_relay_io, thread_stop, (thd, mi));
  thd->reset_query();
  thd->reset_db(NULL, 0);
  if (mysql)
  {
    /*
      Here we need to clear the active VIO before closing the
      connection with the master.  The reason is that THD::awake()
      might be called from terminate_slave_thread() because somebody
      issued a STOP SLAVE.  If that happends, the close_active_vio()
      can be called in the middle of closing the VIO associated with
      the 'mysql' object, causing a crash.
    */
#ifdef SIGNAL_WITH_VIO_CLOSE
    thd->clear_active_vio();
#endif
    mysql_close(mysql);
    mi->mysql=0;
  }
  write_ignored_events_info_to_relay_log(thd, mi);
  thd_proc_info(thd, "Waiting for slave mutex on exit");
  mysql_mutex_lock(&mi->run_lock);

  /* Forget the relay log's format */
  delete mi->rli.relay_log.description_event_for_queue;
  mi->rli.relay_log.description_event_for_queue= 0;
  // TODO: make rpl_status part of Master_info
  change_rpl_status(RPL_ACTIVE_SLAVE,RPL_IDLE_SLAVE);
  DBUG_ASSERT(thd->net.buff != 0);
  net_end(&thd->net); // destructor will not free it, because net.vio is 0
  mysql_mutex_lock(&LOCK_thread_count);
  THD_CHECK_SENTRY(thd);
  delete thd;
  mysql_mutex_unlock(&LOCK_thread_count);
  mi->abort_slave= 0;
  mi->slave_running= 0;
  mi->io_thd= 0;
  /*
    Note: the order of the two following calls (first broadcast, then unlock)
    is important. Otherwise a killer_thread can execute between the calls and
    delete the mi structure leading to a crash! (see BUG#25306 for details)
   */ 
  mysql_cond_broadcast(&mi->stop_cond);       // tell the world we are done
  DBUG_EXECUTE_IF("simulate_slave_delay_at_terminate_bug38694", sleep(5););
  mysql_mutex_unlock(&mi->run_lock);

  DBUG_LEAVE;                                   // Must match DBUG_ENTER()
  my_thread_end();
  pthread_exit(0);
  return 0;                                     // Avoid compiler warnings
}

/*
  Check the temporary directory used by commands like
  LOAD DATA INFILE.
 */
static 
int check_temp_dir(char* tmp_file)
{
  int fd;
  MY_DIR *dirp;
  char tmp_dir[FN_REFLEN];
  size_t tmp_dir_size;

  DBUG_ENTER("check_temp_dir");

  /*
    Get the directory from the temporary file.
  */
  dirname_part(tmp_dir, tmp_file, &tmp_dir_size);

  /*
    Check if the directory exists.
   */
  if (!(dirp=my_dir(tmp_dir,MYF(MY_WME))))
    DBUG_RETURN(1);
  my_dirend(dirp);

  /*
    Check permissions to create a file.
   */
  if ((fd= mysql_file_create(key_file_misc,
                             tmp_file, CREATE_MODE,
                             O_WRONLY | O_BINARY | O_EXCL | O_NOFOLLOW,
                             MYF(MY_WME))) < 0)
  DBUG_RETURN(1);

  /*
    Clean up.
   */
  mysql_file_close(fd, MYF(0));
  mysql_file_delete(key_file_misc, tmp_file, MYF(0));

  DBUG_RETURN(0);
}

/**
  Slave SQL thread entry point.

  @param arg Pointer to Relay_log_info object that holds information
  for the SQL thread.

  @return Always 0.
*/
pthread_handler_t handle_slave_sql(void *arg)
{
  THD *thd;                     /* needs to be first for thread_stack */
  char llbuff[22],llbuff1[22];
  char saved_log_name[FN_REFLEN];
  char saved_master_log_name[FN_REFLEN];
  my_off_t UNINIT_VAR(saved_log_pos);
  my_off_t UNINIT_VAR(saved_master_log_pos);
  my_off_t saved_skip= 0;

  Relay_log_info* rli = &((Master_info*)arg)->rli;
  const char *errmsg;

  // needs to call my_thread_init(), otherwise we get a coredump in DBUG_ stuff
  my_thread_init();
  DBUG_ENTER("handle_slave_sql");

  DBUG_ASSERT(rli->inited);
  mysql_mutex_lock(&rli->run_lock);
  DBUG_ASSERT(!rli->slave_running);
  errmsg= 0;
#ifndef DBUG_OFF
  rli->events_till_abort = abort_slave_event_count;
#endif

  thd = new THD; // note that contructor of THD uses DBUG_ !
  thd->thread_stack = (char*)&thd; // remember where our stack is
  rli->sql_thd= thd;
  
  /* Inform waiting threads that slave has started */
  rli->slave_run_id++;
  rli->slave_running = 1;

  pthread_detach_this_thread();
  if (init_slave_thread(thd, SLAVE_THD_SQL))
  {
    /*
      TODO: this is currently broken - slave start and change master
      will be stuck if we fail here
    */
    mysql_cond_broadcast(&rli->start_cond);
    mysql_mutex_unlock(&rli->run_lock);
    rli->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR, 
                "Failed during slave thread initialization");
    goto err;
  }
  thd->init_for_queries();
  thd->temporary_tables = rli->save_temporary_tables; // restore temp tables
  set_thd_in_use_temporary_tables(rli);   // (re)set sql_thd in use for saved temp tables
  mysql_mutex_lock(&LOCK_thread_count);
  threads.append(thd);
  mysql_mutex_unlock(&LOCK_thread_count);
  /*
    We are going to set slave_running to 1. Assuming slave I/O thread is
    alive and connected, this is going to make Seconds_Behind_Master be 0
    i.e. "caught up". Even if we're just at start of thread. Well it's ok, at
    the moment we start we can think we are caught up, and the next second we
    start receiving data so we realize we are not caught up and
    Seconds_Behind_Master grows. No big deal.
  */
  rli->abort_slave = 0;
  mysql_mutex_unlock(&rli->run_lock);
  mysql_cond_broadcast(&rli->start_cond);

  /*
    Reset errors for a clean start (otherwise, if the master is idle, the SQL
    thread may execute no Query_log_event, so the error will remain even
    though there's no problem anymore). Do not reset the master timestamp
    (imagine the slave has caught everything, the STOP SLAVE and START SLAVE:
    as we are not sure that we are going to receive a query, we want to
    remember the last master timestamp (to say how many seconds behind we are
    now.
    But the master timestamp is reset by RESET SLAVE & CHANGE MASTER.
  */
  rli->clear_error();

  //tell the I/O thread to take relay_log_space_limit into account from now on
  mysql_mutex_lock(&rli->log_space_lock);
  rli->ignore_log_space_limit= 0;
  mysql_mutex_unlock(&rli->log_space_lock);
  rli->trans_retries= 0; // start from "no error"
  DBUG_PRINT("info", ("rli->trans_retries: %lu", rli->trans_retries));

  if (init_relay_log_pos(rli,
                         rli->group_relay_log_name,
                         rli->group_relay_log_pos,
                         1 /*need data lock*/, &errmsg,
                         1 /*look for a description_event*/))
  { 
    rli->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR, 
                "Error initializing relay log position: %s", errmsg);
    goto err;
  }
  THD_CHECK_SENTRY(thd);
#ifndef DBUG_OFF
  {
    char llbuf1[22], llbuf2[22];
    DBUG_PRINT("info", ("my_b_tell(rli->cur_log)=%s rli->event_relay_log_pos=%s",
                        llstr(my_b_tell(rli->cur_log),llbuf1),
                        llstr(rli->event_relay_log_pos,llbuf2)));
    DBUG_ASSERT(rli->event_relay_log_pos >= BIN_LOG_HEADER_SIZE);
    /*
      Wonder if this is correct. I (Guilhem) wonder if my_b_tell() returns the
      correct position when it's called just after my_b_seek() (the questionable
      stuff is those "seek is done on next read" comments in the my_b_seek()
      source code).
      The crude reality is that this assertion randomly fails whereas
      replication seems to work fine. And there is no easy explanation why it
      fails (as we my_b_seek(rli->event_relay_log_pos) at the very end of
      init_relay_log_pos() called above). Maybe the assertion would be
      meaningful if we held rli->data_lock between the my_b_seek() and the
      DBUG_ASSERT().
    */
#ifdef SHOULD_BE_CHECKED
    DBUG_ASSERT(my_b_tell(rli->cur_log) == rli->event_relay_log_pos);
#endif
  }
#endif
  DBUG_ASSERT(rli->sql_thd == thd);

  DBUG_PRINT("master_info",("log_file_name: %s  position: %s",
                            rli->group_master_log_name,
                            llstr(rli->group_master_log_pos,llbuff)));
  if (global_system_variables.log_warnings)
    sql_print_information("Slave SQL thread initialized, starting replication in \
log '%s' at position %s, relay log '%s' position: %s", RPL_LOG_NAME,
                    llstr(rli->group_master_log_pos,llbuff),rli->group_relay_log_name,
                    llstr(rli->group_relay_log_pos,llbuff1));

  if (check_temp_dir(rli->slave_patternload_file))
  {
    rli->report(ERROR_LEVEL, thd->stmt_da->sql_errno(), 
                "Unable to use slave's temporary directory %s - %s", 
                slave_load_tmpdir, thd->stmt_da->message());
    goto err;
  }

  /* execute init_slave variable */
  if (opt_init_slave.length)
  {
    execute_init_command(thd, &opt_init_slave, &LOCK_sys_init_slave);
    if (thd->is_slave_error)
    {
      rli->report(ERROR_LEVEL, thd->stmt_da->sql_errno(),
                  "Slave SQL thread aborted. Can't execute init_slave query");
      goto err;
    }
  }

  /*
    First check until condition - probably there is nothing to execute. We
    do not want to wait for next event in this case.
  */
  mysql_mutex_lock(&rli->data_lock);
  if (rli->slave_skip_counter)
  {
    strmake(saved_log_name, rli->group_relay_log_name, FN_REFLEN - 1);
    strmake(saved_master_log_name, rli->group_master_log_name, FN_REFLEN - 1);
    saved_log_pos= rli->group_relay_log_pos;
    saved_master_log_pos= rli->group_master_log_pos;
    saved_skip= rli->slave_skip_counter;
  }
  if (rli->until_condition != Relay_log_info::UNTIL_NONE &&
      rli->is_until_satisfied(thd, NULL))
  {
    char buf[22];
    sql_print_information("Slave SQL thread stopped because it reached its"
                          " UNTIL position %s", llstr(rli->until_pos(), buf));
    mysql_mutex_unlock(&rli->data_lock);
    goto err;
  }
  mysql_mutex_unlock(&rli->data_lock);

  /* Read queries from the IO/THREAD until this thread is killed */

  while (!sql_slave_killed(thd,rli))
  {
    thd_proc_info(thd, "Reading event from the relay log");
    DBUG_ASSERT(rli->sql_thd == thd);
    THD_CHECK_SENTRY(thd);

    if (saved_skip && rli->slave_skip_counter == 0)
    {
      sql_print_information("'SQL_SLAVE_SKIP_COUNTER=%ld' executed at "
        "relay_log_file='%s', relay_log_pos='%ld', master_log_name='%s', "
        "master_log_pos='%ld' and new position at "
        "relay_log_file='%s', relay_log_pos='%ld', master_log_name='%s', "
        "master_log_pos='%ld' ",
        (ulong) saved_skip, saved_log_name, (ulong) saved_log_pos,
        saved_master_log_name, (ulong) saved_master_log_pos,
        rli->group_relay_log_name, (ulong) rli->group_relay_log_pos,
        rli->group_master_log_name, (ulong) rli->group_master_log_pos);
      saved_skip= 0;
    }
    
    if (exec_relay_log_event(thd,rli))
    {
      DBUG_PRINT("info", ("exec_relay_log_event() failed"));
      // do not scare the user if SQL thread was simply killed or stopped
      if (!sql_slave_killed(thd,rli))
      {
        /*
          retrieve as much info as possible from the thd and, error
          codes and warnings and print this to the error log as to
          allow the user to locate the error
        */
        uint32 const last_errno= rli->last_error().number;

        if (thd->is_error())
        {
          char const *const errmsg= thd->stmt_da->message();

          DBUG_PRINT("info",
                     ("thd->stmt_da->sql_errno()=%d; rli->last_error.number=%d",
                      thd->stmt_da->sql_errno(), last_errno));
          if (last_errno == 0)
          {
            /*
 	      This function is reporting an error which was not reported
 	      while executing exec_relay_log_event().
 	    */ 
            rli->report(ERROR_LEVEL, thd->stmt_da->sql_errno(), "%s", errmsg);
          }
          else if (last_errno != thd->stmt_da->sql_errno())
          {
            /*
             * An error was reported while executing exec_relay_log_event()
             * however the error code differs from what is in the thread.
             * This function prints out more information to help finding
             * what caused the problem.
             */  
            sql_print_error("Slave (additional info): %s Error_code: %d",
                            errmsg, thd->stmt_da->sql_errno());
          }
        }

        /* Print any warnings issued */
        List_iterator_fast<MYSQL_ERROR> it(thd->warning_info->warn_list());
        MYSQL_ERROR *err;
        /*
          Added controlled slave thread cancel for replication
          of user-defined variables.
        */
        bool udf_error = false;
        while ((err= it++))
        {
          if (err->get_sql_errno() == ER_CANT_OPEN_LIBRARY)
            udf_error = true;
          sql_print_warning("Slave: %s Error_code: %d", err->get_message_text(), err->get_sql_errno());
        }
        if (udf_error)
          sql_print_error("Error loading user-defined library, slave SQL "
            "thread aborted. Install the missing library, and restart the "
            "slave SQL thread with \"SLAVE START\". We stopped at log '%s' "
            "position %s", RPL_LOG_NAME, llstr(rli->group_master_log_pos, 
            llbuff));
        else
          sql_print_error("\
Error running query, slave SQL thread aborted. Fix the problem, and restart \
the slave SQL thread with \"SLAVE START\". We stopped at log \
'%s' position %s", RPL_LOG_NAME, llstr(rli->group_master_log_pos, llbuff));
      }
      goto err;
    }
  }

  /* Thread stopped. Print the current replication position to the log */
  sql_print_information("Slave SQL thread exiting, replication stopped in log "
                        "'%s' at position %s",
                        RPL_LOG_NAME, llstr(rli->group_master_log_pos,llbuff));

 err:

  /*
    Some events set some playgrounds, which won't be cleared because thread
    stops. Stopping of this thread may not be known to these events ("stop"
    request is detected only by the present function, not by events), so we
    must "proactively" clear playgrounds:
  */
  thd->clear_error();
  rli->cleanup_context(thd, 1);
  /*
    Some extra safety, which should not been needed (normally, event deletion
    should already have done these assignments (each event which sets these
    variables is supposed to set them to 0 before terminating)).
  */
  thd->catalog= 0;
  thd->reset_query();
  thd->reset_db(NULL, 0);
  thd_proc_info(thd, "Waiting for slave mutex on exit");
  mysql_mutex_lock(&rli->run_lock);
  /* We need data_lock, at least to wake up any waiting master_pos_wait() */
  mysql_mutex_lock(&rli->data_lock);
  DBUG_ASSERT(rli->slave_running == 1); // tracking buffer overrun
  /* When master_pos_wait() wakes up it will check this and terminate */
  rli->slave_running= 0;
  /* Forget the relay log's format */
  delete rli->relay_log.description_event_for_exec;
  rli->relay_log.description_event_for_exec= 0;
  /* Wake up master_pos_wait() */
  mysql_mutex_unlock(&rli->data_lock);
  DBUG_PRINT("info",("Signaling possibly waiting master_pos_wait() functions"));
  mysql_cond_broadcast(&rli->data_cond);
  rli->ignore_log_space_limit= 0; /* don't need any lock */
  /* we die so won't remember charset - re-update them on next thread start */
  rli->cached_charset_invalidate();
  rli->save_temporary_tables = thd->temporary_tables;

  /*
    TODO: see if we can do this conditionally in next_event() instead
    to avoid unneeded position re-init
  */
  thd->temporary_tables = 0; // remove tempation from destructor to close them
  DBUG_ASSERT(thd->net.buff != 0);
  net_end(&thd->net); // destructor will not free it, because we are weird
  DBUG_ASSERT(rli->sql_thd == thd);
  THD_CHECK_SENTRY(thd);
  rli->sql_thd= 0;
  set_thd_in_use_temporary_tables(rli);  // (re)set sql_thd in use for saved temp tables
  mysql_mutex_lock(&LOCK_thread_count);
  THD_CHECK_SENTRY(thd);
  delete thd;
  mysql_mutex_unlock(&LOCK_thread_count);
 /*
  Note: the order of the broadcast and unlock calls below (first broadcast, then unlock)
  is important. Otherwise a killer_thread can execute between the calls and
  delete the mi structure leading to a crash! (see BUG#25306 for details)
 */ 
  mysql_cond_broadcast(&rli->stop_cond);
  DBUG_EXECUTE_IF("simulate_slave_delay_at_terminate_bug38694", sleep(5););
  mysql_mutex_unlock(&rli->run_lock);  // tell the world we are done

  DBUG_LEAVE;                                   // Must match DBUG_ENTER()
  my_thread_end();
  pthread_exit(0);
  return 0;                                     // Avoid compiler warnings
}


/*
  process_io_create_file()
*/

static int process_io_create_file(Master_info* mi, Create_file_log_event* cev)
{
  int error = 1;
  ulong num_bytes;
  bool cev_not_written;
  THD *thd = mi->io_thd;
  NET *net = &mi->mysql->net;
  DBUG_ENTER("process_io_create_file");

  if (unlikely(!cev->is_valid()))
    DBUG_RETURN(1);

  if (!rpl_filter->db_ok(cev->db))
  {
    skip_load_data_infile(net);
    DBUG_RETURN(0);
  }
  DBUG_ASSERT(cev->inited_from_old);
  thd->file_id = cev->file_id = mi->file_id++;
  thd->server_id = cev->server_id;
  cev_not_written = 1;

  if (unlikely(net_request_file(net,cev->fname)))
  {
    sql_print_error("Slave I/O: failed requesting download of '%s'",
                    cev->fname);
    goto err;
  }

  /*
    This dummy block is so we could instantiate Append_block_log_event
    once and then modify it slightly instead of doing it multiple times
    in the loop
  */
  {
    Append_block_log_event aev(thd,0,0,0,0);

    for (;;)
    {
      if (unlikely((num_bytes=my_net_read(net)) == packet_error))
      {
        sql_print_error("Network read error downloading '%s' from master",
                        cev->fname);
        goto err;
      }
      if (unlikely(!num_bytes)) /* eof */
      {
	/* 3.23 master wants it */
        net_write_command(net, 0, (uchar*) "", 0, (uchar*) "", 0);
        /*
          If we wrote Create_file_log_event, then we need to write
          Execute_load_log_event. If we did not write Create_file_log_event,
          then this is an empty file and we can just do as if the LOAD DATA
          INFILE had not existed, i.e. write nothing.
        */
        if (unlikely(cev_not_written))
          break;
        Execute_load_log_event xev(thd,0,0);
        xev.log_pos = cev->log_pos;
        if (unlikely(mi->rli.relay_log.append(&xev)))
        {
          mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                     ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
                     "error writing Exec_load event to relay log");
          goto err;
        }
        mi->rli.relay_log.harvest_bytes_written(&mi->rli.log_space_total);
        break;
      }
      if (unlikely(cev_not_written))
      {
        cev->block = net->read_pos;
        cev->block_len = num_bytes;
        if (unlikely(mi->rli.relay_log.append(cev)))
        {
          mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                     ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
                     "error writing Create_file event to relay log");
          goto err;
        }
        cev_not_written=0;
        mi->rli.relay_log.harvest_bytes_written(&mi->rli.log_space_total);
      }
      else
      {
        aev.block = net->read_pos;
        aev.block_len = num_bytes;
        aev.log_pos = cev->log_pos;
        if (unlikely(mi->rli.relay_log.append(&aev)))
        {
          mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                     ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
                     "error writing Append_block event to relay log");
          goto err;
        }
        mi->rli.relay_log.harvest_bytes_written(&mi->rli.log_space_total) ;
      }
    }
  }
  error=0;
err:
  DBUG_RETURN(error);
}


/*
  Start using a new binary log on the master

  SYNOPSIS
    process_io_rotate()
    mi                  master_info for the slave
    rev                 The rotate log event read from the binary log

  DESCRIPTION
    Updates the master info with the place in the next binary
    log where we should start reading.
    Rotate the relay log to avoid mixed-format relay logs.

  NOTES
    We assume we already locked mi->data_lock

  RETURN VALUES
    0           ok
    1           Log event is illegal

*/

static int process_io_rotate(Master_info *mi, Rotate_log_event *rev)
{
  DBUG_ENTER("process_io_rotate");
  mysql_mutex_assert_owner(&mi->data_lock);

  if (unlikely(!rev->is_valid()))
    DBUG_RETURN(1);

  /* Safe copy as 'rev' has been "sanitized" in Rotate_log_event's ctor */
  memcpy(mi->master_log_name, rev->new_log_ident, rev->ident_len+1);
  mi->master_log_pos= rev->pos;
  DBUG_PRINT("info", ("master_log_pos: '%s' %lu",
                      mi->master_log_name, (ulong) mi->master_log_pos));
#ifndef DBUG_OFF
  /*
    If we do not do this, we will be getting the first
    rotate event forever, so we need to not disconnect after one.
  */
  if (disconnect_slave_event_count)
    mi->events_till_disconnect++;
#endif

  /*
    If description_event_for_queue is format <4, there is conversion in the
    relay log to the slave's format (4). And Rotate can mean upgrade or
    nothing. If upgrade, it's to 5.0 or newer, so we will get a Format_desc, so
    no need to reset description_event_for_queue now. And if it's nothing (same
    master version as before), no need (still using the slave's format).
  */
  if (mi->rli.relay_log.description_event_for_queue->binlog_version >= 4)
  {
    delete mi->rli.relay_log.description_event_for_queue;
    /* start from format 3 (MySQL 4.0) again */
    mi->rli.relay_log.description_event_for_queue= new
      Format_description_log_event(3);
  }
  /*
    Rotate the relay log makes binlog format detection easier (at next slave
    start or mysqlbinlog)
  */
  DBUG_RETURN(rotate_relay_log(mi) /* will take the right mutexes */);
}

/*
  Reads a 3.23 event and converts it to the slave's format. This code was
  copied from MySQL 4.0.
*/
static int queue_binlog_ver_1_event(Master_info *mi, const char *buf,
                           ulong event_len)
{
  const char *errmsg = 0;
  ulong inc_pos;
  bool ignore_event= 0;
  char *tmp_buf = 0;
  Relay_log_info *rli= &mi->rli;
  DBUG_ENTER("queue_binlog_ver_1_event");

  /*
    If we get Load event, we need to pass a non-reusable buffer
    to read_log_event, so we do a trick
  */
  if (buf[EVENT_TYPE_OFFSET] == LOAD_EVENT)
  {
    if (unlikely(!(tmp_buf=(char*)my_malloc(event_len+1,MYF(MY_WME)))))
    {
      mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
                 ER(ER_SLAVE_FATAL_ERROR), "Memory allocation failed");
      DBUG_RETURN(1);
    }
    memcpy(tmp_buf,buf,event_len);
    /*
      Create_file constructor wants a 0 as last char of buffer, this 0 will
      serve as the string-termination char for the file's name (which is at the
      end of the buffer)
      We must increment event_len, otherwise the event constructor will not see
      this end 0, which leads to segfault.
    */
    tmp_buf[event_len++]=0;
    int4store(tmp_buf+EVENT_LEN_OFFSET, event_len);
    buf = (const char*)tmp_buf;
  }
  /*
    This will transform LOAD_EVENT into CREATE_FILE_EVENT, ask the master to
    send the loaded file, and write it to the relay log in the form of
    Append_block/Exec_load (the SQL thread needs the data, as that thread is not
    connected to the master).
  */
  Log_event *ev = Log_event::read_log_event(buf,event_len, &errmsg,
                                            mi->rli.relay_log.description_event_for_queue);
  if (unlikely(!ev))
  {
    sql_print_error("Read invalid event from master: '%s',\
 master could be corrupt but a more likely cause of this is a bug",
                    errmsg);
    my_free(tmp_buf);
    DBUG_RETURN(1);
  }

  mysql_mutex_lock(&mi->data_lock);
  ev->log_pos= mi->master_log_pos; /* 3.23 events don't contain log_pos */
  switch (ev->get_type_code()) {
  case STOP_EVENT:
    ignore_event= 1;
    inc_pos= event_len;
    break;
  case ROTATE_EVENT:
    if (unlikely(process_io_rotate(mi,(Rotate_log_event*)ev)))
    {
      delete ev;
      mysql_mutex_unlock(&mi->data_lock);
      DBUG_RETURN(1);
    }
    inc_pos= 0;
    break;
  case CREATE_FILE_EVENT:
    /*
      Yes it's possible to have CREATE_FILE_EVENT here, even if we're in
      queue_old_event() which is for 3.23 events which don't comprise
      CREATE_FILE_EVENT. This is because read_log_event() above has just
      transformed LOAD_EVENT into CREATE_FILE_EVENT.
    */
  {
    /* We come here when and only when tmp_buf != 0 */
    DBUG_ASSERT(tmp_buf != 0);
    inc_pos=event_len;
    ev->log_pos+= inc_pos;
    int error = process_io_create_file(mi,(Create_file_log_event*)ev);
    delete ev;
    mi->master_log_pos += inc_pos;
    DBUG_PRINT("info", ("master_log_pos: %lu", (ulong) mi->master_log_pos));
    mysql_mutex_unlock(&mi->data_lock);
    my_free(tmp_buf);
    DBUG_RETURN(error);
  }
  default:
    inc_pos= event_len;
    break;
  }
  if (likely(!ignore_event))
  {
    if (ev->log_pos)
      /*
         Don't do it for fake Rotate events (see comment in
      Log_event::Log_event(const char* buf...) in log_event.cc).
      */
      ev->log_pos+= event_len; /* make log_pos be the pos of the end of the event */
    if (unlikely(rli->relay_log.append(ev)))
    {
      delete ev;
      mysql_mutex_unlock(&mi->data_lock);
      DBUG_RETURN(1);
    }
    rli->relay_log.harvest_bytes_written(&rli->log_space_total);
  }
  delete ev;
  mi->master_log_pos+= inc_pos;
  DBUG_PRINT("info", ("master_log_pos: %lu", (ulong) mi->master_log_pos));
  mysql_mutex_unlock(&mi->data_lock);
  DBUG_RETURN(0);
}

/*
  Reads a 4.0 event and converts it to the slave's format. This code was copied
  from queue_binlog_ver_1_event(), with some affordable simplifications.
*/
static int queue_binlog_ver_3_event(Master_info *mi, const char *buf,
                           ulong event_len)
{
  const char *errmsg = 0;
  ulong inc_pos;
  char *tmp_buf = 0;
  Relay_log_info *rli= &mi->rli;
  DBUG_ENTER("queue_binlog_ver_3_event");

  /* read_log_event() will adjust log_pos to be end_log_pos */
  Log_event *ev = Log_event::read_log_event(buf,event_len, &errmsg,
                                            mi->rli.relay_log.description_event_for_queue);
  if (unlikely(!ev))
  {
    sql_print_error("Read invalid event from master: '%s',\
 master could be corrupt but a more likely cause of this is a bug",
                    errmsg);
    my_free(tmp_buf);
    DBUG_RETURN(1);
  }
  mysql_mutex_lock(&mi->data_lock);
  switch (ev->get_type_code()) {
  case STOP_EVENT:
    goto err;
  case ROTATE_EVENT:
    if (unlikely(process_io_rotate(mi,(Rotate_log_event*)ev)))
    {
      delete ev;
      mysql_mutex_unlock(&mi->data_lock);
      DBUG_RETURN(1);
    }
    inc_pos= 0;
    break;
  default:
    inc_pos= event_len;
    break;
  }
  if (unlikely(rli->relay_log.append(ev)))
  {
    delete ev;
    mysql_mutex_unlock(&mi->data_lock);
    DBUG_RETURN(1);
  }
  rli->relay_log.harvest_bytes_written(&rli->log_space_total);
  delete ev;
  mi->master_log_pos+= inc_pos;
err:
  DBUG_PRINT("info", ("master_log_pos: %lu", (ulong) mi->master_log_pos));
  mysql_mutex_unlock(&mi->data_lock);
  DBUG_RETURN(0);
}

/*
  queue_old_event()

  Writes a 3.23 or 4.0 event to the relay log, after converting it to the 5.0
  (exactly, slave's) format. To do the conversion, we create a 5.0 event from
  the 3.23/4.0 bytes, then write this event to the relay log.

  TODO:
    Test this code before release - it has to be tested on a separate
    setup with 3.23 master or 4.0 master
*/

static int queue_old_event(Master_info *mi, const char *buf,
                           ulong event_len)
{
  DBUG_ENTER("queue_old_event");

  switch (mi->rli.relay_log.description_event_for_queue->binlog_version)
  {
  case 1:
      DBUG_RETURN(queue_binlog_ver_1_event(mi,buf,event_len));
  case 3:
      DBUG_RETURN(queue_binlog_ver_3_event(mi,buf,event_len));
  default: /* unsupported format; eg version 2 */
    DBUG_PRINT("info",("unsupported binlog format %d in queue_old_event()",
                       mi->rli.relay_log.description_event_for_queue->binlog_version));
    DBUG_RETURN(1);
  }
}

/*
  queue_event()

  If the event is 3.23/4.0, passes it to queue_old_event() which will convert
  it. Otherwise, writes a 5.0 (or newer) event to the relay log. Then there is
  no format conversion, it's pure read/write of bytes.
  So a 5.0.0 slave's relay log can contain events in the slave's format or in
  any >=5.0.0 format.
*/

static int queue_event(Master_info* mi,const char* buf, ulong event_len)
{
  int error= 0;
  String error_msg;
  ulong inc_pos;
  Relay_log_info *rli= &mi->rli;
  mysql_mutex_t *log_lock= rli->relay_log.get_log_lock();
  ulong s_id;
  DBUG_ENTER("queue_event");

  LINT_INIT(inc_pos);

  if (mi->rli.relay_log.description_event_for_queue->binlog_version<4 &&
      buf[EVENT_TYPE_OFFSET] != FORMAT_DESCRIPTION_EVENT /* a way to escape */)
    DBUG_RETURN(queue_old_event(mi,buf,event_len));

  LINT_INIT(inc_pos);
  mysql_mutex_lock(&mi->data_lock);

  switch (buf[EVENT_TYPE_OFFSET]) {
  case STOP_EVENT:
    /*
      We needn't write this event to the relay log. Indeed, it just indicates a
      master server shutdown. The only thing this does is cleaning. But
      cleaning is already done on a per-master-thread basis (as the master
      server is shutting down cleanly, it has written all DROP TEMPORARY TABLE
      prepared statements' deletion are TODO only when we binlog prep stmts).

      We don't even increment mi->master_log_pos, because we may be just after
      a Rotate event. Btw, in a few milliseconds we are going to have a Start
      event from the next binlog (unless the master is presently running
      without --log-bin).
    */
    goto err;
  case ROTATE_EVENT:
  {
    Rotate_log_event rev(buf,event_len,mi->rli.relay_log.description_event_for_queue);
    if (unlikely(process_io_rotate(mi,&rev)))
    {
      error= ER_SLAVE_RELAY_LOG_WRITE_FAILURE;
      goto err;
    }
    /*
      Now the I/O thread has just changed its mi->master_log_name, so
      incrementing mi->master_log_pos is nonsense.
    */
    inc_pos= 0;
    break;
  }
  case FORMAT_DESCRIPTION_EVENT:
  {
    /*
      Create an event, and save it (when we rotate the relay log, we will have
      to write this event again).
    */
    /*
      We are the only thread which reads/writes description_event_for_queue.
      The relay_log struct does not move (though some members of it can
      change), so we needn't any lock (no rli->data_lock, no log lock).
    */
    Format_description_log_event* tmp;
    const char* errmsg;
    if (!(tmp= (Format_description_log_event*)
          Log_event::read_log_event(buf, event_len, &errmsg,
                                    mi->rli.relay_log.description_event_for_queue)))
    {
      error= ER_SLAVE_RELAY_LOG_WRITE_FAILURE;
      goto err;
    }
    delete mi->rli.relay_log.description_event_for_queue;
    mi->rli.relay_log.description_event_for_queue= tmp;
    /*
       Though this does some conversion to the slave's format, this will
       preserve the master's binlog format version, and number of event types.
    */
    /*
       If the event was not requested by the slave (the slave did not ask for
       it), i.e. has end_log_pos=0, we do not increment mi->master_log_pos
    */
    inc_pos= uint4korr(buf+LOG_POS_OFFSET) ? event_len : 0;
    DBUG_PRINT("info",("binlog format is now %d",
                       mi->rli.relay_log.description_event_for_queue->binlog_version));

  }
  break;

  case HEARTBEAT_LOG_EVENT:
  {
    /*
      HB (heartbeat) cannot come before RL (Relay)
    */
    char  llbuf[22];
    Heartbeat_log_event hb(buf, event_len, mi->rli.relay_log.description_event_for_queue);
    if (!hb.is_valid())
    {
      error= ER_SLAVE_HEARTBEAT_FAILURE;
      error_msg.append(STRING_WITH_LEN("inconsistent heartbeat event content;"));
      error_msg.append(STRING_WITH_LEN("the event's data: log_file_name "));
      error_msg.append(hb.get_log_ident(), (uint) strlen(hb.get_log_ident()));
      error_msg.append(STRING_WITH_LEN(" log_pos "));
      llstr(hb.log_pos, llbuf);
      error_msg.append(llbuf, strlen(llbuf));
      goto err;
    }
    mi->received_heartbeats++;
    /* 
       compare local and event's versions of log_file, log_pos.
       
       Heartbeat is sent only after an event corresponding to the corrdinates
       the heartbeat carries.
       Slave can not have a difference in coordinates except in the only
       special case when mi->master_log_name, master_log_pos have never
       been updated by Rotate event i.e when slave does not have any history
       with the master (and thereafter mi->master_log_pos is NULL).

       TODO: handling `when' for SHOW SLAVE STATUS' snds behind
    */
    if ((memcmp(mi->master_log_name, hb.get_log_ident(), hb.get_ident_len())
         && mi->master_log_name != NULL)
        || mi->master_log_pos != hb.log_pos)
    {
      /* missed events of heartbeat from the past */
      error= ER_SLAVE_HEARTBEAT_FAILURE;
      error_msg.append(STRING_WITH_LEN("heartbeat is not compatible with local info;"));
      error_msg.append(STRING_WITH_LEN("the event's data: log_file_name "));
      error_msg.append(hb.get_log_ident(), (uint) strlen(hb.get_log_ident()));
      error_msg.append(STRING_WITH_LEN(" log_pos "));
      llstr(hb.log_pos, llbuf);
      error_msg.append(llbuf, strlen(llbuf));
      goto err;
    }
    goto skip_relay_logging;
  }
  break;

  default:
    inc_pos= event_len;
    break;
  }

  /*
     If this event is originating from this server, don't queue it.
     We don't check this for 3.23 events because it's simpler like this; 3.23
     will be filtered anyway by the SQL slave thread which also tests the
     server id (we must also keep this test in the SQL thread, in case somebody
     upgrades a 4.0 slave which has a not-filtered relay log).

     ANY event coming from ourselves can be ignored: it is obvious for queries;
     for STOP_EVENT/ROTATE_EVENT/START_EVENT: these cannot come from ourselves
     (--log-slave-updates would not log that) unless this slave is also its
     direct master (an unsupported, useless setup!).
  */

  mysql_mutex_lock(log_lock);
  s_id= uint4korr(buf + SERVER_ID_OFFSET);
  if ((s_id == ::server_id && !mi->rli.replicate_same_server_id) ||
      /*
        the following conjunction deals with IGNORE_SERVER_IDS, if set
        If the master is on the ignore list, execution of
        format description log events and rotate events is necessary.
      */
      (mi->ignore_server_ids.elements > 0 &&
       mi->shall_ignore_server_id(s_id) &&
       /* everything is filtered out from non-master */
       (s_id != mi->master_id ||
        /* for the master meta information is necessary */
        (buf[EVENT_TYPE_OFFSET] != FORMAT_DESCRIPTION_EVENT &&
         buf[EVENT_TYPE_OFFSET] != ROTATE_EVENT))))
  {
    /*
      Do not write it to the relay log.
      a) We still want to increment mi->master_log_pos, so that we won't
      re-read this event from the master if the slave IO thread is now
      stopped/restarted (more efficient if the events we are ignoring are big
      LOAD DATA INFILE).
      b) We want to record that we are skipping events, for the information of
      the slave SQL thread, otherwise that thread may let
      rli->group_relay_log_pos stay too small if the last binlog's event is
      ignored.
      But events which were generated by this slave and which do not exist in
      the master's binlog (i.e. Format_desc, Rotate & Stop) should not increment
      mi->master_log_pos.
      If the event is originated remotely and is being filtered out by
      IGNORE_SERVER_IDS it increments mi->master_log_pos
      as well as rli->group_relay_log_pos.
    */
    if (!(s_id == ::server_id && !mi->rli.replicate_same_server_id) ||
        (buf[EVENT_TYPE_OFFSET] != FORMAT_DESCRIPTION_EVENT &&
         buf[EVENT_TYPE_OFFSET] != ROTATE_EVENT &&
         buf[EVENT_TYPE_OFFSET] != STOP_EVENT))
    {
      mi->master_log_pos+= inc_pos;
      memcpy(rli->ign_master_log_name_end, mi->master_log_name, FN_REFLEN);
      DBUG_ASSERT(rli->ign_master_log_name_end[0]);
      rli->ign_master_log_pos_end= mi->master_log_pos;
    }
    rli->relay_log.signal_update(); // the slave SQL thread needs to re-check
    DBUG_PRINT("info", ("master_log_pos: %lu, event originating from %u server, ignored",
                        (ulong) mi->master_log_pos, uint4korr(buf + SERVER_ID_OFFSET)));
  }
  else
  {
    /* write the event to the relay log */
    if (likely(!(rli->relay_log.appendv(buf,event_len,0))))
    {
      mi->master_log_pos+= inc_pos;
      DBUG_PRINT("info", ("master_log_pos: %lu", (ulong) mi->master_log_pos));
      rli->relay_log.harvest_bytes_written(&rli->log_space_total);
    }
    else
    {
      error= ER_SLAVE_RELAY_LOG_WRITE_FAILURE;
    }
    rli->ign_master_log_name_end[0]= 0; // last event is not ignored
  }
  mysql_mutex_unlock(log_lock);

skip_relay_logging:
  
err:
  mysql_mutex_unlock(&mi->data_lock);
  DBUG_PRINT("info", ("error: %d", error));
  if (error)
    mi->report(ERROR_LEVEL, error, ER(error), 
               (error == ER_SLAVE_RELAY_LOG_WRITE_FAILURE)?
               "could not queue event from master" :
               error_msg.ptr());
  DBUG_RETURN(error);
}


void end_relay_log_info(Relay_log_info* rli)
{
  DBUG_ENTER("end_relay_log_info");

  if (!rli->inited)
    DBUG_VOID_RETURN;
  if (rli->info_fd >= 0)
  {
    end_io_cache(&rli->info_file);
    mysql_file_close(rli->info_fd, MYF(MY_WME));
    rli->info_fd = -1;
  }
  if (rli->cur_log_fd >= 0)
  {
    end_io_cache(&rli->cache_buf);
    mysql_file_close(rli->cur_log_fd, MYF(MY_WME));
    rli->cur_log_fd = -1;
  }
  rli->inited = 0;
  rli->relay_log.close(LOG_CLOSE_INDEX | LOG_CLOSE_STOP_EVENT);
  rli->relay_log.harvest_bytes_written(&rli->log_space_total);
  /*
    Delete the slave's temporary tables from memory.
    In the future there will be other actions than this, to ensure persistance
    of slave's temp tables after shutdown.
  */
  rli->close_temporary_tables();
  DBUG_VOID_RETURN;
}


/**
  Hook to detach the active VIO before closing a connection handle.

  The client API might close the connection (and associated data)
  in case it encounters a unrecoverable (network) error. This hook
  is called from the client code before the VIO handle is deleted
  allows the thread to detach the active vio so it does not point
  to freed memory.

  Other calls to THD::clear_active_vio throughout this module are
  redundant due to the hook but are left in place for illustrative
  purposes.
*/

extern "C" void slave_io_thread_detach_vio()
{
#ifdef SIGNAL_WITH_VIO_CLOSE
  THD *thd= current_thd;
  if (thd && thd->slave_thread)
    thd->clear_active_vio();
#endif
}


/*
  Try to connect until successful or slave killed

  SYNPOSIS
    safe_connect()
    thd                 Thread handler for slave
    mysql               MySQL connection handle
    mi                  Replication handle

  RETURN
    0   ok
    #   Error
*/

static int safe_connect(THD* thd, MYSQL* mysql, Master_info* mi)
{
  DBUG_ENTER("safe_connect");

  DBUG_RETURN(connect_to_master(thd, mysql, mi, 0, 0));
}


/*
  SYNPOSIS
    connect_to_master()

  IMPLEMENTATION
    Try to connect until successful or slave killed or we have retried
    master_retry_count times
*/

static int connect_to_master(THD* thd, MYSQL* mysql, Master_info* mi,
                             bool reconnect, bool suppress_warnings)
{
  int slave_was_killed;
  int last_errno= -2;                           // impossible error
  ulong err_count=0;
  char llbuff[22];
  DBUG_ENTER("connect_to_master");

#ifndef DBUG_OFF
  mi->events_till_disconnect = disconnect_slave_event_count;
#endif
  ulong client_flag= CLIENT_REMEMBER_OPTIONS;
  if (opt_slave_compressed_protocol)
    client_flag=CLIENT_COMPRESS;                /* We will use compression */

  mysql_options(mysql, MYSQL_OPT_CONNECT_TIMEOUT, (char *) &slave_net_timeout);
  mysql_options(mysql, MYSQL_OPT_READ_TIMEOUT, (char *) &slave_net_timeout);

#ifdef HAVE_OPENSSL
  if (mi->ssl)
  {
    mysql_ssl_set(mysql,
                  mi->ssl_key[0]?mi->ssl_key:0,
                  mi->ssl_cert[0]?mi->ssl_cert:0,
                  mi->ssl_ca[0]?mi->ssl_ca:0,
                  mi->ssl_capath[0]?mi->ssl_capath:0,
                  mi->ssl_cipher[0]?mi->ssl_cipher:0);
    mysql_options(mysql, MYSQL_OPT_SSL_VERIFY_SERVER_CERT,
                  &mi->ssl_verify_server_cert);
  }
#endif

  mysql_options(mysql, MYSQL_SET_CHARSET_NAME, default_charset_info->csname);
  /* This one is not strictly needed but we have it here for completeness */
  mysql_options(mysql, MYSQL_SET_CHARSET_DIR, (char *) charsets_dir);

  while (!(slave_was_killed = io_slave_killed(thd,mi)) &&
         (reconnect ? mysql_reconnect(mysql) != 0 :
          mysql_real_connect(mysql, mi->host, mi->user, mi->password, 0,
                             mi->port, 0, client_flag) == 0))
  {
    /* Don't repeat last error */
    if ((int)mysql_errno(mysql) != last_errno)
    {
      last_errno=mysql_errno(mysql);
      suppress_warnings= 0;
      mi->report(ERROR_LEVEL, last_errno,
                 "error %s to master '%s@%s:%d'"
                 " - retry-time: %d  retries: %lu",
                 (reconnect ? "reconnecting" : "connecting"),
                 mi->user, mi->host, mi->port,
                 mi->connect_retry, master_retry_count);
    }
    /*
      By default we try forever. The reason is that failure will trigger
      master election, so if the user did not set master_retry_count we
      do not want to have election triggered on the first failure to
      connect
    */
    if (++err_count == master_retry_count)
    {
      slave_was_killed=1;
      if (reconnect)
        change_rpl_status(RPL_ACTIVE_SLAVE,RPL_LOST_SOLDIER);
      break;
    }
    safe_sleep(thd,mi->connect_retry,(CHECK_KILLED_FUNC)io_slave_killed,
               (void*)mi);
  }

  if (!slave_was_killed)
  {
    mi->clear_error(); // clear possible left over reconnect error
    if (reconnect)
    {
      if (!suppress_warnings && global_system_variables.log_warnings)
        sql_print_information("Slave: connected to master '%s@%s:%d',\
replication resumed in log '%s' at position %s", mi->user,
                        mi->host, mi->port,
                        IO_RPL_LOG_NAME,
                        llstr(mi->master_log_pos,llbuff));
    }
    else
    {
      change_rpl_status(RPL_IDLE_SLAVE,RPL_ACTIVE_SLAVE);
      general_log_print(thd, COM_CONNECT_OUT, "%s@%s:%d",
                        mi->user, mi->host, mi->port);
    }
#ifdef SIGNAL_WITH_VIO_CLOSE
    thd->set_active_vio(mysql->net.vio);
#endif
  }
  mysql->reconnect= 1;
  DBUG_PRINT("exit",("slave_was_killed: %d", slave_was_killed));
  DBUG_RETURN(slave_was_killed);
}


/*
  safe_reconnect()

  IMPLEMENTATION
    Try to connect until successful or slave killed or we have retried
    master_retry_count times
*/

static int safe_reconnect(THD* thd, MYSQL* mysql, Master_info* mi,
                          bool suppress_warnings)
{
  DBUG_ENTER("safe_reconnect");
  DBUG_RETURN(connect_to_master(thd, mysql, mi, 1, suppress_warnings));
}


MYSQL *rpl_connect_master(MYSQL *mysql)
{
  THD *thd= current_thd;
  Master_info *mi= my_pthread_getspecific_ptr(Master_info*, RPL_MASTER_INFO);
  if (!mi)
  {
    sql_print_error("'rpl_connect_master' must be called in slave I/O thread context.");
    return NULL;
  }

  bool allocated= false;
  
  if (!mysql)
  {
    if(!(mysql= mysql_init(NULL)))
    {
      sql_print_error("rpl_connect_master: failed in mysql_init()");
      return NULL;
    }
    allocated= true;
  }

  /*
    XXX: copied from connect_to_master, this function should not
    change the slave status, so we cannot use connect_to_master
    directly
    
    TODO: make this part a seperate function to eliminate duplication
  */
  mysql_options(mysql, MYSQL_OPT_CONNECT_TIMEOUT, (char *) &slave_net_timeout);
  mysql_options(mysql, MYSQL_OPT_READ_TIMEOUT, (char *) &slave_net_timeout);

#ifdef HAVE_OPENSSL
  if (mi->ssl)
  {
    mysql_ssl_set(mysql,
                  mi->ssl_key[0]?mi->ssl_key:0,
                  mi->ssl_cert[0]?mi->ssl_cert:0,
                  mi->ssl_ca[0]?mi->ssl_ca:0,
                  mi->ssl_capath[0]?mi->ssl_capath:0,
                  mi->ssl_cipher[0]?mi->ssl_cipher:0);
    mysql_options(mysql, MYSQL_OPT_SSL_VERIFY_SERVER_CERT,
                  &mi->ssl_verify_server_cert);
  }
#endif

  mysql_options(mysql, MYSQL_SET_CHARSET_NAME, default_charset_info->csname);
  /* This one is not strictly needed but we have it here for completeness */
  mysql_options(mysql, MYSQL_SET_CHARSET_DIR, (char *) charsets_dir);

  if (io_slave_killed(thd, mi)
      || !mysql_real_connect(mysql, mi->host, mi->user, mi->password, 0,
                             mi->port, 0, 0))
  {
    if (!io_slave_killed(thd, mi))
      sql_print_error("rpl_connect_master: error connecting to master: %s (server_error: %d)",
                      mysql_error(mysql), mysql_errno(mysql));
    
    if (allocated)
      mysql_close(mysql);                       // this will free the object
    return NULL;
  }
  return mysql;
}

/*
  Store the file and position where the execute-slave thread are in the
  relay log.

  SYNOPSIS
    flush_relay_log_info()
    rli                 Relay log information

  NOTES
    - As this is only called by the slave thread or on STOP SLAVE, with the
      log_lock grabbed and the slave thread stopped, we don't need to have 
      a lock here.
    - If there is an active transaction, then we don't update the position
      in the relay log.  This is to ensure that we re-execute statements
      if we die in the middle of an transaction that was rolled back.
    - As a transaction never spans binary logs, we don't have to handle the
      case where we do a relay-log-rotation in the middle of the transaction.
      If this would not be the case, we would have to ensure that we
      don't delete the relay log file where the transaction started when
      we switch to a new relay log file.

  TODO
    - Change the log file information to a binary format to avoid calling
      longlong2str.

  RETURN VALUES
    0   ok
    1   write error
*/

bool flush_relay_log_info(Relay_log_info* rli)
{
  bool error=0;
  DBUG_ENTER("flush_relay_log_info");

  if (unlikely(rli->no_storage))
    DBUG_RETURN(0);

  IO_CACHE *file = &rli->info_file;
  char buff[FN_REFLEN*2+22*2+4], *pos;

  my_b_seek(file, 0L);
  pos=strmov(buff, rli->group_relay_log_name);
  *pos++='\n';
  pos=longlong2str(rli->group_relay_log_pos, pos, 10);
  *pos++='\n';
  pos=strmov(pos, rli->group_master_log_name);
  *pos++='\n';
  pos=longlong2str(rli->group_master_log_pos, pos, 10);
  *pos='\n';
  if (my_b_write(file, (uchar*) buff, (size_t) (pos-buff)+1))
    error=1;
  if (flush_io_cache(file))
    error=1;
  if (sync_relayloginfo_period &&
      !error &&
      ++(rli->sync_counter) >= sync_relayloginfo_period)
  {
    if (my_sync(rli->info_fd, MYF(MY_WME)))
      error=1;
    rli->sync_counter= 0;
  }
  /* 
    Flushing the relay log is done by the slave I/O thread 
    or by the user on STOP SLAVE. 
   */
  DBUG_RETURN(error);
}


/*
  Called when we notice that the current "hot" log got rotated under our feet.
*/

static IO_CACHE *reopen_relay_log(Relay_log_info *rli, const char **errmsg)
{
  DBUG_ENTER("reopen_relay_log");
  DBUG_ASSERT(rli->cur_log != &rli->cache_buf);
  DBUG_ASSERT(rli->cur_log_fd == -1);

  IO_CACHE *cur_log = rli->cur_log=&rli->cache_buf;
  if ((rli->cur_log_fd=open_binlog(cur_log,rli->event_relay_log_name,
                                   errmsg)) <0)
    DBUG_RETURN(0);
  /*
    We want to start exactly where we was before:
    relay_log_pos       Current log pos
    pending             Number of bytes already processed from the event
  */
  rli->event_relay_log_pos= max(rli->event_relay_log_pos, BIN_LOG_HEADER_SIZE);
  my_b_seek(cur_log,rli->event_relay_log_pos);
  DBUG_RETURN(cur_log);
}


/**
  Reads next event from the relay log.  Should be called from the
  slave IO thread.

  @param rli Relay_log_info structure for the slave IO thread.

  @return The event read, or NULL on error.  If an error occurs, the
  error is reported through the sql_print_information() or
  sql_print_error() functions.
*/
static Log_event* next_event(Relay_log_info* rli)
{
  Log_event* ev;
  IO_CACHE* cur_log = rli->cur_log;
  mysql_mutex_t *log_lock = rli->relay_log.get_log_lock();
  const char* errmsg=0;
  THD* thd = rli->sql_thd;
  DBUG_ENTER("next_event");

  DBUG_ASSERT(thd != 0);

#ifndef DBUG_OFF
  if (abort_slave_event_count && !rli->events_till_abort--)
    DBUG_RETURN(0);
#endif

  /*
    For most operations we need to protect rli members with data_lock,
    so we assume calling function acquired this mutex for us and we will
    hold it for the most of the loop below However, we will release it
    whenever it is worth the hassle,  and in the cases when we go into a
    mysql_cond_wait() with the non-data_lock mutex
  */
  mysql_mutex_assert_owner(&rli->data_lock);

  while (!sql_slave_killed(thd,rli))
  {
    /*
      We can have two kinds of log reading:
      hot_log:
        rli->cur_log points at the IO_CACHE of relay_log, which
        is actively being updated by the I/O thread. We need to be careful
        in this case and make sure that we are not looking at a stale log that
        has already been rotated. If it has been, we reopen the log.

      The other case is much simpler:
        We just have a read only log that nobody else will be updating.
    */
    bool hot_log;
    if ((hot_log = (cur_log != &rli->cache_buf)))
    {
      DBUG_ASSERT(rli->cur_log_fd == -1); // foreign descriptor
      mysql_mutex_lock(log_lock);

      /*
        Reading xxx_file_id is safe because the log will only
        be rotated when we hold relay_log.LOCK_log
      */
      if (rli->relay_log.get_open_count() != rli->cur_log_old_open_count)
      {
        // The master has switched to a new log file; Reopen the old log file
        cur_log=reopen_relay_log(rli, &errmsg);
        mysql_mutex_unlock(log_lock);
        if (!cur_log)                           // No more log files
          goto err;
        hot_log=0;                              // Using old binary log
      }
    }
    /* 
      As there is no guarantee that the relay is open (for example, an I/O
      error during a write by the slave I/O thread may have closed it), we
      have to test it.
    */
    if (!my_b_inited(cur_log))
      goto err;
#ifndef DBUG_OFF
    {
      /* This is an assertion which sometimes fails, let's try to track it */
      char llbuf1[22], llbuf2[22];
      DBUG_PRINT("info", ("my_b_tell(cur_log)=%s rli->event_relay_log_pos=%s",
                          llstr(my_b_tell(cur_log),llbuf1),
                          llstr(rli->event_relay_log_pos,llbuf2)));
      DBUG_ASSERT(my_b_tell(cur_log) >= BIN_LOG_HEADER_SIZE);
      DBUG_ASSERT(my_b_tell(cur_log) == rli->event_relay_log_pos);
    }
#endif
    /*
      Relay log is always in new format - if the master is 3.23, the
      I/O thread will convert the format for us.
      A problem: the description event may be in a previous relay log. So if
      the slave has been shutdown meanwhile, we would have to look in old relay
      logs, which may even have been deleted. So we need to write this
      description event at the beginning of the relay log.
      When the relay log is created when the I/O thread starts, easy: the
      master will send the description event and we will queue it.
      But if the relay log is created by new_file(): then the solution is:
      MYSQL_BIN_LOG::open() will write the buffered description event.
    */
    if ((ev=Log_event::read_log_event(cur_log,0,
                                      rli->relay_log.description_event_for_exec)))

    {
      DBUG_ASSERT(thd==rli->sql_thd);
      /*
        read it while we have a lock, to avoid a mutex lock in
        inc_event_relay_log_pos()
      */
      rli->future_event_relay_log_pos= my_b_tell(cur_log);
      if (hot_log)
        mysql_mutex_unlock(log_lock);
      DBUG_RETURN(ev);
    }
    DBUG_ASSERT(thd==rli->sql_thd);
    if (opt_reckless_slave)                     // For mysql-test
      cur_log->error = 0;
    if (cur_log->error < 0)
    {
      errmsg = "slave SQL thread aborted because of I/O error";
      if (hot_log)
        mysql_mutex_unlock(log_lock);
      goto err;
    }
    if (!cur_log->error) /* EOF */
    {
      /*
        On a hot log, EOF means that there are no more updates to
        process and we must block until I/O thread adds some and
        signals us to continue
      */
      if (hot_log)
      {
        /*
          We say in Seconds_Behind_Master that we have "caught up". Note that
          for example if network link is broken but I/O slave thread hasn't
          noticed it (slave_net_timeout not elapsed), then we'll say "caught
          up" whereas we're not really caught up. Fixing that would require
          internally cutting timeout in smaller pieces in network read, no
          thanks. Another example: SQL has caught up on I/O, now I/O has read
          a new event and is queuing it; the false "0" will exist until SQL
          finishes executing the new event; it will be look abnormal only if
          the events have old timestamps (then you get "many", 0, "many").

          Transient phases like this can be fixed with implemeting
          Heartbeat event which provides the slave the status of the
          master at time the master does not have any new update to send.
          Seconds_Behind_Master would be zero only when master has no
          more updates in binlog for slave. The heartbeat can be sent
          in a (small) fraction of slave_net_timeout. Until it's done
          rli->last_master_timestamp is temporarely (for time of
          waiting for the following event) reset whenever EOF is
          reached.
        */
        time_t save_timestamp= rli->last_master_timestamp;
        rli->last_master_timestamp= 0;

        DBUG_ASSERT(rli->relay_log.get_open_count() ==
                    rli->cur_log_old_open_count);

        if (rli->ign_master_log_name_end[0])
        {
          /* We generate and return a Rotate, to make our positions advance */
          DBUG_PRINT("info",("seeing an ignored end segment"));
          ev= new Rotate_log_event(rli->ign_master_log_name_end,
                                   0, rli->ign_master_log_pos_end,
                                   Rotate_log_event::DUP_NAME);
          rli->ign_master_log_name_end[0]= 0;
          mysql_mutex_unlock(log_lock);
          if (unlikely(!ev))
          {
            errmsg= "Slave SQL thread failed to create a Rotate event "
              "(out of memory?), SHOW SLAVE STATUS may be inaccurate";
            goto err;
          }
          ev->server_id= 0; // don't be ignored by slave SQL thread
          DBUG_RETURN(ev);
        }

        /*
          We can, and should release data_lock while we are waiting for
          update. If we do not, show slave status will block
        */
        mysql_mutex_unlock(&rli->data_lock);

        /*
          Possible deadlock :
          - the I/O thread has reached log_space_limit
          - the SQL thread has read all relay logs, but cannot purge for some
          reason:
            * it has already purged all logs except the current one
            * there are other logs than the current one but they're involved in
            a transaction that finishes in the current one (or is not finished)
          Solution :
          Wake up the possibly waiting I/O thread, and set a boolean asking
          the I/O thread to temporarily ignore the log_space_limit
          constraint, because we do not want the I/O thread to block because of
          space (it's ok if it blocks for any other reason (e.g. because the
          master does not send anything). Then the I/O thread stops waiting
          and reads more events.
          The SQL thread decides when the I/O thread should take log_space_limit
          into account again : ignore_log_space_limit is reset to 0
          in purge_first_log (when the SQL thread purges the just-read relay
          log), and also when the SQL thread starts. We should also reset
          ignore_log_space_limit to 0 when the user does RESET SLAVE, but in
          fact, no need as RESET SLAVE requires that the slave
          be stopped, and the SQL thread sets ignore_log_space_limit to 0 when
          it stops.
        */
        mysql_mutex_lock(&rli->log_space_lock);
        // prevent the I/O thread from blocking next times
        rli->ignore_log_space_limit= 1;
        /*
          If the I/O thread is blocked, unblock it.  Ok to broadcast
          after unlock, because the mutex is only destroyed in
          ~Relay_log_info(), i.e. when rli is destroyed, and rli will
          not be destroyed before we exit the present function.
        */
        mysql_mutex_unlock(&rli->log_space_lock);
        mysql_cond_broadcast(&rli->log_space_cond);
        // Note that wait_for_update_relay_log unlocks lock_log !
        rli->relay_log.wait_for_update_relay_log(rli->sql_thd);
        // re-acquire data lock since we released it earlier
        mysql_mutex_lock(&rli->data_lock);
        rli->last_master_timestamp= save_timestamp;
        continue;
      }
      /*
        If the log was not hot, we need to move to the next log in
        sequence. The next log could be hot or cold, we deal with both
        cases separately after doing some common initialization
      */
      end_io_cache(cur_log);
      DBUG_ASSERT(rli->cur_log_fd >= 0);
      mysql_file_close(rli->cur_log_fd, MYF(MY_WME));
      rli->cur_log_fd = -1;

      if (relay_log_purge)
      {
        /*
          purge_first_log will properly set up relay log coordinates in rli.
          If the group's coordinates are equal to the event's coordinates
          (i.e. the relay log was not rotated in the middle of a group),
          we can purge this relay log too.
          We do ulonglong and string comparisons, this may be slow but
          - purging the last relay log is nice (it can save 1GB of disk), so we
          like to detect the case where we can do it, and given this,
          - I see no better detection method
          - purge_first_log is not called that often
        */
        if (rli->relay_log.purge_first_log
            (rli,
             rli->group_relay_log_pos == rli->event_relay_log_pos
             && !strcmp(rli->group_relay_log_name,rli->event_relay_log_name)))
        {
          errmsg = "Error purging processed logs";
          goto err;
        }
      }
      else
      {
        /*
          If hot_log is set, then we already have a lock on
          LOCK_log.  If not, we have to get the lock.

          According to Sasha, the only time this code will ever be executed
          is if we are recovering from a bug.
        */
        if (rli->relay_log.find_next_log(&rli->linfo, !hot_log))
        {
          errmsg = "error switching to the next log";
          goto err;
        }
        rli->event_relay_log_pos = BIN_LOG_HEADER_SIZE;
        strmake(rli->event_relay_log_name,rli->linfo.log_file_name,
                sizeof(rli->event_relay_log_name)-1);
        flush_relay_log_info(rli);
      }

      /*
        Now we want to open this next log. To know if it's a hot log (the one
        being written by the I/O thread now) or a cold log, we can use
        is_active(); if it is hot, we use the I/O cache; if it's cold we open
        the file normally. But if is_active() reports that the log is hot, this
        may change between the test and the consequence of the test. So we may
        open the I/O cache whereas the log is now cold, which is nonsense.
        To guard against this, we need to have LOCK_log.
      */

      DBUG_PRINT("info",("hot_log: %d",hot_log));
      if (!hot_log) /* if hot_log, we already have this mutex */
        mysql_mutex_lock(log_lock);
      if (rli->relay_log.is_active(rli->linfo.log_file_name))
      {
#ifdef EXTRA_DEBUG
        if (global_system_variables.log_warnings)
          sql_print_information("next log '%s' is currently active",
                                rli->linfo.log_file_name);
#endif
        rli->cur_log= cur_log= rli->relay_log.get_log_file();
        rli->cur_log_old_open_count= rli->relay_log.get_open_count();
        DBUG_ASSERT(rli->cur_log_fd == -1);

        /*
           When the SQL thread is [stopped and] (re)started the
           following may happen:

           1. Log was hot at stop time and remains hot at restart

              SQL thread reads again from hot_log (SQL thread was
              reading from the active log when it was stopped and the
              very same log is still active on SQL thread restart).

              In this case, my_b_seek is performed on cur_log, while
              cur_log points to relay_log.get_log_file();

           2. Log was hot at stop time but got cold before restart

              The log was hot when SQL thread stopped, but it is not
              anymore when the SQL thread restarts.

              In this case, the SQL thread reopens the log, using
              cache_buf, ie, cur_log points to &cache_buf, and thence
              its coordinates are reset.

           3. Log was already cold at stop time

              The log was not hot when the SQL thread stopped, and, of
              course, it will not be hot when it restarts.

              In this case, the SQL thread opens the cold log again,
              using cache_buf, ie, cur_log points to &cache_buf, and
              thence its coordinates are reset.

           4. Log was hot at stop time, DBA changes to previous cold
              log and restarts SQL thread

              The log was hot when the SQL thread was stopped, but the
              user changed the coordinates of the SQL thread to
              restart from a previous cold log.

              In this case, at start time, cur_log points to a cold
              log, opened using &cache_buf as cache, and coordinates
              are reset. However, as it moves on to the next logs, it
              will eventually reach the hot log. If the hot log is the
              same at the time the SQL thread was stopped, then
              coordinates were not reset - the cur_log will point to
              relay_log.get_log_file(), and not a freshly opened
              IO_CACHE through cache_buf. For this reason we need to
              deploy a my_b_seek before calling check_binlog_magic at
              this point of the code (see: BUG#55263 for more
              details).
          
          NOTES: 
            - We must keep the LOCK_log to read the 4 first bytes, as
              this is a hot log (same as when we call read_log_event()
              above: for a hot log we take the mutex).

            - Because of scenario #4 above, we need to have a
              my_b_seek here. Otherwise, we might hit the assertion
              inside check_binlog_magic.
        */

        my_b_seek(cur_log, (my_off_t) 0);
        if (check_binlog_magic(cur_log,&errmsg))
        {
          if (!hot_log)
            mysql_mutex_unlock(log_lock);
          goto err;
        }
        if (!hot_log)
          mysql_mutex_unlock(log_lock);
        continue;
      }
      if (!hot_log)
        mysql_mutex_unlock(log_lock);
      /*
        if we get here, the log was not hot, so we will have to open it
        ourselves. We are sure that the log is still not hot now (a log can get
        from hot to cold, but not from cold to hot). No need for LOCK_log.
      */
#ifdef EXTRA_DEBUG
      if (global_system_variables.log_warnings)
        sql_print_information("next log '%s' is not active",
                              rli->linfo.log_file_name);
#endif
      // open_binlog() will check the magic header
      if ((rli->cur_log_fd=open_binlog(cur_log,rli->linfo.log_file_name,
                                       &errmsg)) <0)
        goto err;
    }
    else
    {
      /*
        Read failed with a non-EOF error.
        TODO: come up with something better to handle this error
      */
      if (hot_log)
        mysql_mutex_unlock(log_lock);
      sql_print_error("Slave SQL thread: I/O error reading \
event(errno: %d  cur_log->error: %d)",
                      my_errno,cur_log->error);
      // set read position to the beginning of the event
      my_b_seek(cur_log,rli->event_relay_log_pos);
      /* otherwise, we have had a partial read */
      errmsg = "Aborting slave SQL thread because of partial event read";
      break;                                    // To end of function
    }
  }
  if (!errmsg && global_system_variables.log_warnings)
  {
    sql_print_information("Error reading relay log event: %s",
                          "slave SQL thread was killed");
    DBUG_RETURN(0);
  }

err:
  if (errmsg)
    sql_print_error("Error reading relay log event: %s", errmsg);
  DBUG_RETURN(0);
}

/*
  Rotate a relay log (this is used only by FLUSH LOGS; the automatic rotation
  because of size is simpler because when we do it we already have all relevant
  locks; here we don't, so this function is mainly taking locks).
  Returns nothing as we cannot catch any error (MYSQL_BIN_LOG::new_file()
  is void).
*/

int rotate_relay_log(Master_info* mi)
{
  DBUG_ENTER("rotate_relay_log");
  Relay_log_info* rli= &mi->rli;
  int error= 0;

  DBUG_EXECUTE_IF("crash_before_rotate_relaylog", DBUG_SUICIDE(););

  /*
     We need to test inited because otherwise, new_file() will attempt to lock
     LOCK_log, which may not be inited (if we're not a slave).
  */
  if (!rli->inited)
  {
    DBUG_PRINT("info", ("rli->inited == 0"));
    goto end;
  }

  /* If the relay log is closed, new_file() will do nothing. */
  if ((error= rli->relay_log.new_file()))
    goto end;

  /*
    We harvest now, because otherwise BIN_LOG_HEADER_SIZE will not immediately
    be counted, so imagine a succession of FLUSH LOGS  and assume the slave
    threads are started:
    relay_log_space decreases by the size of the deleted relay log, but does
    not increase, so flush-after-flush we may become negative, which is wrong.
    Even if this will be corrected as soon as a query is replicated on the
    slave (because the I/O thread will then call harvest_bytes_written() which
    will harvest all these BIN_LOG_HEADER_SIZE we forgot), it may give strange
    output in SHOW SLAVE STATUS meanwhile. So we harvest now.
    If the log is closed, then this will just harvest the last writes, probably
    0 as they probably have been harvested.
  */
  rli->relay_log.harvest_bytes_written(&rli->log_space_total);
end:
  DBUG_RETURN(error);
}


/**
   Detects, based on master's version (as found in the relay log), if master
   has a certain bug.
   @param rli Relay_log_info which tells the master's version
   @param bug_id Number of the bug as found in bugs.mysql.com
   @param report bool report error message, default TRUE

   @param pred Predicate function that will be called with @c param to
   check for the bug. If the function return @c true, the bug is present,
   otherwise, it is not.

   @param param  State passed to @c pred function.

   @return TRUE if master has the bug, FALSE if it does not.
*/
bool rpl_master_has_bug(const Relay_log_info *rli, uint bug_id, bool report,
                        bool (*pred)(const void *), const void *param)
{
  struct st_version_range_for_one_bug {
    uint        bug_id;
    const uchar introduced_in[3]; // first version with bug
    const uchar fixed_in[3];      // first version with fix
  };
  static struct st_version_range_for_one_bug versions_for_all_bugs[]=
  {
    {24432, { 5, 0, 24 }, { 5, 0, 38 } },
    {24432, { 5, 1, 12 }, { 5, 1, 17 } },
    {33029, { 5, 0,  0 }, { 5, 0, 58 } },
    {33029, { 5, 1,  0 }, { 5, 1, 12 } },
    {37426, { 5, 1,  0 }, { 5, 1, 26 } },
  };
  const uchar *master_ver=
    rli->relay_log.description_event_for_exec->server_version_split;

  DBUG_ASSERT(sizeof(rli->relay_log.description_event_for_exec->server_version_split) == 3);

  for (uint i= 0;
       i < sizeof(versions_for_all_bugs)/sizeof(*versions_for_all_bugs);i++)
  {
    const uchar *introduced_in= versions_for_all_bugs[i].introduced_in,
      *fixed_in= versions_for_all_bugs[i].fixed_in;
    if ((versions_for_all_bugs[i].bug_id == bug_id) &&
        (memcmp(introduced_in, master_ver, 3) <= 0) &&
        (memcmp(fixed_in,      master_ver, 3) >  0) &&
        (pred == NULL || (*pred)(param)))
    {
      if (!report)
	return TRUE;
      // a short message for SHOW SLAVE STATUS (message length constraints)
      my_printf_error(ER_UNKNOWN_ERROR, "master may suffer from"
                      " http://bugs.mysql.com/bug.php?id=%u"
                      " so slave stops; check error log on slave"
                      " for more info", MYF(0), bug_id);
      // a verbose message for the error log
      rli->report(ERROR_LEVEL, ER_UNKNOWN_ERROR,
                  "According to the master's version ('%s'),"
                  " it is probable that master suffers from this bug:"
                      " http://bugs.mysql.com/bug.php?id=%u"
                      " and thus replicating the current binary log event"
                      " may make the slave's data become different from the"
                      " master's data."
                      " To take no risk, slave refuses to replicate"
                      " this event and stops."
                      " We recommend that all updates be stopped on the"
                      " master and slave, that the data of both be"
                      " manually synchronized,"
                      " that master's binary logs be deleted,"
                      " that master be upgraded to a version at least"
                      " equal to '%d.%d.%d'. Then replication can be"
                      " restarted.",
                      rli->relay_log.description_event_for_exec->server_version,
                      bug_id,
                      fixed_in[0], fixed_in[1], fixed_in[2]);
      return TRUE;
    }
  }
  return FALSE;
}

/**
   BUG#33029, For all 5.0 up to 5.0.58 exclusive, and 5.1 up to 5.1.12
   exclusive, if one statement in a SP generated AUTO_INCREMENT value
   by the top statement, all statements after it would be considered
   generated AUTO_INCREMENT value by the top statement, and a
   erroneous INSERT_ID value might be associated with these statement,
   which could cause duplicate entry error and stop the slave.

   Detect buggy master to work around.
 */
bool rpl_master_erroneous_autoinc(THD *thd)
{
  if (active_mi && active_mi->rli.sql_thd == thd)
  {
    Relay_log_info *rli= &active_mi->rli;
    DBUG_EXECUTE_IF("simulate_bug33029", return TRUE;);
    return rpl_master_has_bug(rli, 33029, FALSE, NULL, NULL);
  }
  return FALSE;
}

#ifdef HAVE_EXPLICIT_TEMPLATE_INSTANTIATION
template class I_List_iterator<i_string>;
template class I_List_iterator<i_string_pair>;
#endif

/**
  @} (end of group Replication)
*/

#endif /* HAVE_REPLICATION */