1
/*-------------------------------------------------------------------------
4
* PostgreSQL transaction log manager
7
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
8
* Portions Copyright (c) 1994, Regents of the University of California
10
* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.180.4.2 2005-04-15 22:49:45 momjian Exp $
12
*-------------------------------------------------------------------------
25
#include "access/clog.h"
26
#include "access/subtrans.h"
27
#include "access/xact.h"
28
#include "access/xlog.h"
29
#include "access/xlog_internal.h"
30
#include "access/xlogutils.h"
31
#include "catalog/catversion.h"
32
#include "catalog/pg_control.h"
33
#include "miscadmin.h"
34
#include "postmaster/bgwriter.h"
35
#include "storage/bufpage.h"
36
#include "storage/fd.h"
37
#include "storage/lwlock.h"
38
#include "storage/pmsignal.h"
39
#include "storage/proc.h"
40
#include "storage/sinval.h"
41
#include "storage/spin.h"
42
#include "utils/builtins.h"
43
#include "utils/guc.h"
44
#include "utils/relcache.h"
48
* This chunk of hackery attempts to determine which file sync methods
49
* are available on the current platform, and to choose an appropriate
50
* default method. We assume that fsync() is always available, and that
51
* configure determined whether fdatasync() is.
53
#define SYNC_METHOD_FSYNC 0
54
#define SYNC_METHOD_FDATASYNC 1
55
#define SYNC_METHOD_OPEN 2 /* used for both O_SYNC and
59
#define OPEN_SYNC_FLAG O_SYNC
62
#define OPEN_SYNC_FLAG O_FSYNC
67
#if defined(OPEN_SYNC_FLAG)
68
#if O_DSYNC != OPEN_SYNC_FLAG
69
#define OPEN_DATASYNC_FLAG O_DSYNC
71
#else /* !defined(OPEN_SYNC_FLAG) */
72
/* Win32 only has O_DSYNC */
73
#define OPEN_DATASYNC_FLAG O_DSYNC
77
#if defined(OPEN_DATASYNC_FLAG)
78
#define DEFAULT_SYNC_METHOD_STR "open_datasync"
79
#define DEFAULT_SYNC_METHOD SYNC_METHOD_OPEN
80
#define DEFAULT_SYNC_FLAGBIT OPEN_DATASYNC_FLAG
82
#if defined(HAVE_FDATASYNC)
83
#define DEFAULT_SYNC_METHOD_STR "fdatasync"
84
#define DEFAULT_SYNC_METHOD SYNC_METHOD_FDATASYNC
85
#define DEFAULT_SYNC_FLAGBIT 0
87
#ifndef FSYNC_IS_WRITE_THROUGH
88
#define DEFAULT_SYNC_METHOD_STR "fsync"
90
#define DEFAULT_SYNC_METHOD_STR "fsync_writethrough"
92
#define DEFAULT_SYNC_METHOD SYNC_METHOD_FSYNC
93
#define DEFAULT_SYNC_FLAGBIT 0
98
/* User-settable parameters */
99
int CheckPointSegments = 3;
101
char *XLogArchiveCommand = NULL;
102
char *XLOG_sync_method = NULL;
103
const char XLOG_sync_method_default[] = DEFAULT_SYNC_METHOD_STR;
106
bool XLOG_DEBUG = false;
110
* XLOGfileslop is used in the code as the allowed "fuzz" in the number of
111
* preallocated XLOG segments --- we try to have at least XLOGfiles advance
112
* segments but no more than XLOGfileslop segments. This could
113
* be made a separate GUC variable, but at present I think it's sufficient
114
* to hardwire it as 2*CheckPointSegments+1. Under normal conditions, a
115
* checkpoint will free no more than 2*CheckPointSegments log segments, and
116
* we want to recycle all of them; the +1 allows boundary cases to happen
117
* without wasting a delete/create-segment cycle.
120
#define XLOGfileslop (2*CheckPointSegments + 1)
123
/* these are derived from XLOG_sync_method by assign_xlog_sync_method */
124
static int sync_method = DEFAULT_SYNC_METHOD;
125
static int open_sync_bit = DEFAULT_SYNC_FLAGBIT;
127
#define XLOG_SYNC_BIT (enableFsync ? open_sync_bit : 0)
129
#define MinXLOGbuffers 4
133
* ThisTimeLineID will be same in all backends --- it identifies current
134
* WAL timeline for the database system.
136
TimeLineID ThisTimeLineID = 0;
138
/* Are we doing recovery from XLOG? */
139
bool InRecovery = false;
141
/* Are we recovering using offline XLOG archives? */
142
static bool InArchiveRecovery = false;
144
/* Was the last xlog file restored from archive, or local? */
145
static bool restoredFromArchive = false;
147
/* options taken from recovery.conf */
148
static char *recoveryRestoreCommand = NULL;
149
static bool recoveryTarget = false;
150
static bool recoveryTargetExact = false;
151
static bool recoveryTargetInclusive = true;
152
static TransactionId recoveryTargetXid;
153
static time_t recoveryTargetTime;
155
/* if recoveryStopsHere returns true, it saves actual stop xid/time here */
156
static TransactionId recoveryStopXid;
157
static time_t recoveryStopTime;
158
static bool recoveryStopAfter;
160
/* constraint set by read_backup_label */
161
static XLogRecPtr recoveryMinXlogOffset = {0, 0};
164
* During normal operation, the only timeline we care about is ThisTimeLineID.
165
* During recovery, however, things are more complicated. To simplify life
166
* for rmgr code, we keep ThisTimeLineID set to the "current" timeline as we
167
* scan through the WAL history (that is, it is the line that was active when
168
* the currently-scanned WAL record was generated). We also need these
171
* recoveryTargetTLI: the desired timeline that we want to end in.
173
* expectedTLIs: an integer list of recoveryTargetTLI and the TLIs of
174
* its known parents, newest first (so recoveryTargetTLI is always the
175
* first list member). Only these TLIs are expected to be seen in the WAL
176
* segments we read, and indeed only these TLIs will be considered as
177
* candidate WAL files to open at all.
179
* curFileTLI: the TLI appearing in the name of the current input WAL file.
180
* (This is not necessarily the same as ThisTimeLineID, because we could
181
* be scanning data that was copied from an ancestor timeline when the current
182
* file was created.) During a sequential scan we do not allow this value
185
static TimeLineID recoveryTargetTLI;
186
static List *expectedTLIs;
187
static TimeLineID curFileTLI;
190
* MyLastRecPtr points to the start of the last XLOG record inserted by the
191
* current transaction. If MyLastRecPtr.xrecoff == 0, then the current
192
* xact hasn't yet inserted any transaction-controlled XLOG records.
194
* Note that XLOG records inserted outside transaction control are not
195
* reflected into MyLastRecPtr. They do, however, cause MyXactMadeXLogEntry
196
* to be set true. The latter can be used to test whether the current xact
197
* made any loggable changes (including out-of-xact changes, such as
200
* When we insert/update/delete a tuple in a temporary relation, we do not
201
* make any XLOG record, since we don't care about recovering the state of
202
* the temp rel after a crash. However, we will still need to remember
203
* whether our transaction committed or aborted in that case. So, we must
204
* set MyXactMadeTempRelUpdate true to indicate that the XID will be of
207
XLogRecPtr MyLastRecPtr = {0, 0};
209
bool MyXactMadeXLogEntry = false;
211
bool MyXactMadeTempRelUpdate = false;
214
* ProcLastRecPtr points to the start of the last XLOG record inserted by the
215
* current backend. It is updated for all inserts, transaction-controlled
216
* or not. ProcLastRecEnd is similar but points to end+1 of last record.
218
static XLogRecPtr ProcLastRecPtr = {0, 0};
220
XLogRecPtr ProcLastRecEnd = {0, 0};
223
* RedoRecPtr is this backend's local copy of the REDO record pointer
224
* (which is almost but not quite the same as a pointer to the most recent
225
* CHECKPOINT record). We update this from the shared-memory copy,
226
* XLogCtl->Insert.RedoRecPtr, whenever we can safely do so (ie, when we
227
* hold the Insert lock). See XLogInsert for details. We are also allowed
228
* to update from XLogCtl->Insert.RedoRecPtr if we hold the info_lck;
229
* see GetRedoRecPtr. A freshly spawned backend obtains the value during
232
static XLogRecPtr RedoRecPtr;
235
* Shared-memory data structures for XLOG control
237
* LogwrtRqst indicates a byte position that we need to write and/or fsync
238
* the log up to (all records before that point must be written or fsynced).
239
* LogwrtResult indicates the byte positions we have already written/fsynced.
240
* These structs are identical but are declared separately to indicate their
241
* slightly different functions.
243
* We do a lot of pushups to minimize the amount of access to lockable
244
* shared memory values. There are actually three shared-memory copies of
245
* LogwrtResult, plus one unshared copy in each backend. Here's how it works:
246
* XLogCtl->LogwrtResult is protected by info_lck
247
* XLogCtl->Write.LogwrtResult is protected by WALWriteLock
248
* XLogCtl->Insert.LogwrtResult is protected by WALInsertLock
249
* One must hold the associated lock to read or write any of these, but
250
* of course no lock is needed to read/write the unshared LogwrtResult.
252
* XLogCtl->LogwrtResult and XLogCtl->Write.LogwrtResult are both "always
253
* right", since both are updated by a write or flush operation before
254
* it releases WALWriteLock. The point of keeping XLogCtl->Write.LogwrtResult
255
* is that it can be examined/modified by code that already holds WALWriteLock
256
* without needing to grab info_lck as well.
258
* XLogCtl->Insert.LogwrtResult may lag behind the reality of the other two,
259
* but is updated when convenient. Again, it exists for the convenience of
260
* code that is already holding WALInsertLock but not the other locks.
262
* The unshared LogwrtResult may lag behind any or all of these, and again
263
* is updated when convenient.
265
* The request bookkeeping is simpler: there is a shared XLogCtl->LogwrtRqst
266
* (protected by info_lck), but we don't need to cache any copies of it.
268
* Note that this all works because the request and result positions can only
269
* advance forward, never back up, and so we can easily determine which of two
270
* values is "more up to date".
272
* info_lck is only held long enough to read/update the protected variables,
273
* so it's a plain spinlock. The other locks are held longer (potentially
274
* over I/O operations), so we use LWLocks for them. These locks are:
276
* WALInsertLock: must be held to insert a record into the WAL buffers.
278
* WALWriteLock: must be held to write WAL buffers to disk (XLogWrite or
281
* ControlFileLock: must be held to read/update control file or create
284
* CheckpointLock: must be held to do a checkpoint (ensures only one
285
* checkpointer at a time; even though the postmaster won't launch
286
* parallel checkpoint processes, we need this because manual checkpoints
287
* could be launched simultaneously).
292
typedef struct XLogwrtRqst
294
XLogRecPtr Write; /* last byte + 1 to write out */
295
XLogRecPtr Flush; /* last byte + 1 to flush */
298
typedef struct XLogwrtResult
300
XLogRecPtr Write; /* last byte + 1 written out */
301
XLogRecPtr Flush; /* last byte + 1 flushed */
305
* Shared state data for XLogInsert.
307
typedef struct XLogCtlInsert
309
XLogwrtResult LogwrtResult; /* a recent value of LogwrtResult */
310
XLogRecPtr PrevRecord; /* start of previously-inserted record */
311
uint16 curridx; /* current block index in cache */
312
XLogPageHeader currpage; /* points to header of block in cache */
313
char *currpos; /* current insertion point in cache */
314
XLogRecPtr RedoRecPtr; /* current redo point for insertions */
318
* Shared state data for XLogWrite/XLogFlush.
320
typedef struct XLogCtlWrite
322
XLogwrtResult LogwrtResult; /* current value of LogwrtResult */
323
uint16 curridx; /* cache index of next block to write */
327
* Total shared-memory state for XLOG.
329
typedef struct XLogCtlData
331
/* Protected by WALInsertLock: */
332
XLogCtlInsert Insert;
333
/* Protected by info_lck: */
334
XLogwrtRqst LogwrtRqst;
335
XLogwrtResult LogwrtResult;
336
/* Protected by WALWriteLock: */
340
* These values do not change after startup, although the pointed-to
341
* pages and xlblocks values certainly do. Permission to read/write
342
* the pages and xlblocks values depends on WALInsertLock and
345
char *pages; /* buffers for unwritten XLOG pages */
346
XLogRecPtr *xlblocks; /* 1st byte ptr-s + BLCKSZ */
347
uint32 XLogCacheByte; /* # bytes in xlog buffers */
348
uint32 XLogCacheBlck; /* highest allocated xlog buffer index */
349
TimeLineID ThisTimeLineID;
351
slock_t info_lck; /* locks shared LogwrtRqst/LogwrtResult */
354
static XLogCtlData *XLogCtl = NULL;
357
* We maintain an image of pg_control in shared memory.
359
static ControlFileData *ControlFile = NULL;
362
* Macros for managing XLogInsert state. In most cases, the calling routine
363
* has local copies of XLogCtl->Insert and/or XLogCtl->Insert->curridx,
364
* so these are passed as parameters instead of being fetched via XLogCtl.
367
/* Free space remaining in the current xlog page buffer */
368
#define INSERT_FREESPACE(Insert) \
369
(BLCKSZ - ((Insert)->currpos - (char *) (Insert)->currpage))
371
/* Construct XLogRecPtr value for current insertion point */
372
#define INSERT_RECPTR(recptr,Insert,curridx) \
374
(recptr).xlogid = XLogCtl->xlblocks[curridx].xlogid, \
376
XLogCtl->xlblocks[curridx].xrecoff - INSERT_FREESPACE(Insert) \
379
#define PrevBufIdx(idx) \
380
(((idx) == 0) ? XLogCtl->XLogCacheBlck : ((idx) - 1))
382
#define NextBufIdx(idx) \
383
(((idx) == XLogCtl->XLogCacheBlck) ? 0 : ((idx) + 1))
386
/* File path names */
387
char XLogDir[MAXPGPATH];
388
static char ControlFilePath[MAXPGPATH];
391
* Private, possibly out-of-date copy of shared LogwrtResult.
392
* See discussion above.
394
static XLogwrtResult LogwrtResult = {{0, 0}, {0, 0}};
397
* openLogFile is -1 or a kernel FD for an open log file segment.
398
* When it's open, openLogOff is the current seek offset in the file.
399
* openLogId/openLogSeg identify the segment. These variables are only
400
* used to write the XLOG, and so will normally refer to the active segment.
402
static int openLogFile = -1;
403
static uint32 openLogId = 0;
404
static uint32 openLogSeg = 0;
405
static uint32 openLogOff = 0;
408
* These variables are used similarly to the ones above, but for reading
409
* the XLOG. Note, however, that readOff generally represents the offset
410
* of the page just read, not the seek position of the FD itself, which
411
* will be just past that page.
413
static int readFile = -1;
414
static uint32 readId = 0;
415
static uint32 readSeg = 0;
416
static uint32 readOff = 0;
418
/* Buffer for currently read page (BLCKSZ bytes) */
419
static char *readBuf = NULL;
421
/* Buffer for current ReadRecord result (expandable) */
422
static char *readRecordBuf = NULL;
423
static uint32 readRecordBufSize = 0;
425
/* State information for XLOG reading */
426
static XLogRecPtr ReadRecPtr;
427
static XLogRecPtr EndRecPtr;
428
static XLogRecord *nextRecord = NULL;
429
static TimeLineID lastPageTLI = 0;
431
static bool InRedo = false;
434
static void XLogArchiveNotify(const char *xlog);
435
static void XLogArchiveNotifySeg(uint32 log, uint32 seg);
436
static bool XLogArchiveIsDone(const char *xlog);
437
static void XLogArchiveCleanup(const char *xlog);
438
static void readRecoveryCommandFile(void);
439
static void exitArchiveRecovery(TimeLineID endTLI,
440
uint32 endLogId, uint32 endLogSeg);
441
static bool recoveryStopsHere(XLogRecord *record, bool *includeThis);
443
static bool AdvanceXLInsertBuffer(void);
444
static void XLogWrite(XLogwrtRqst WriteRqst);
445
static int XLogFileInit(uint32 log, uint32 seg,
446
bool *use_existent, bool use_lock);
447
static bool InstallXLogFileSegment(uint32 log, uint32 seg, char *tmppath,
448
bool find_free, int max_advance,
450
static int XLogFileOpen(uint32 log, uint32 seg);
451
static int XLogFileRead(uint32 log, uint32 seg, int emode);
452
static bool RestoreArchivedFile(char *path, const char *xlogfname,
453
const char *recovername, off_t expectedSize);
454
static int PreallocXlogFiles(XLogRecPtr endptr);
455
static void MoveOfflineLogs(uint32 log, uint32 seg, XLogRecPtr endptr,
456
int *nsegsremoved, int *nsegsrecycled);
457
static XLogRecord *ReadRecord(XLogRecPtr *RecPtr, int emode);
458
static bool ValidXLOGHeader(XLogPageHeader hdr, int emode);
459
static XLogRecord *ReadCheckpointRecord(XLogRecPtr RecPtr, int whichChkpt);
460
static List *readTimeLineHistory(TimeLineID targetTLI);
461
static bool existsTimeLineHistory(TimeLineID probeTLI);
462
static TimeLineID findNewestTimeLine(TimeLineID startTLI);
463
static void writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
465
uint32 endLogId, uint32 endLogSeg);
466
static void WriteControlFile(void);
467
static void ReadControlFile(void);
468
static char *str_time(time_t tnow);
469
static void issue_xlog_fsync(void);
472
static void xlog_outrec(char *buf, XLogRecord *record);
474
static bool read_backup_label(XLogRecPtr *checkPointLoc);
475
static void remove_backup_label(void);
479
* Insert an XLOG record having the specified RMID and info bytes,
480
* with the body of the record being the data chunk(s) described by
481
* the rdata list (see xlog.h for notes about rdata).
483
* Returns XLOG pointer to end of record (beginning of next record).
484
* This can be used as LSN for data pages affected by the logged action.
485
* (LSN is the XLOG point up to which the XLOG must be flushed to disk
486
* before the data page can be written out. This implements the basic
487
* WAL rule "write the log before the data".)
489
* NB: this routine feels free to scribble on the XLogRecData structs,
490
* though not on the data they reference. This is OK since the XLogRecData
491
* structs are always just temporaries in the calling code.
494
XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata)
496
XLogCtlInsert *Insert = &XLogCtl->Insert;
498
XLogContRecord *contrecord;
500
XLogRecPtr WriteRqst;
504
Buffer dtbuf[XLR_MAX_BKP_BLOCKS];
505
bool dtbuf_bkp[XLR_MAX_BKP_BLOCKS];
506
BkpBlock dtbuf_xlg[XLR_MAX_BKP_BLOCKS];
507
XLogRecPtr dtbuf_lsn[XLR_MAX_BKP_BLOCKS];
508
XLogRecData dtbuf_rdt[2 * XLR_MAX_BKP_BLOCKS];
513
XLogwrtRqst LogwrtRqst;
515
bool no_tran = (rmid == RM_XLOG_ID) ? true : false;
517
if (info & XLR_INFO_MASK)
519
if ((info & XLR_INFO_MASK) != XLOG_NO_TRAN)
520
elog(PANIC, "invalid xlog info mask %02X", (info & XLR_INFO_MASK));
522
info &= ~XLR_INFO_MASK;
526
* In bootstrap mode, we don't actually log anything but XLOG
527
* resources; return a phony record pointer.
529
if (IsBootstrapProcessingMode() && rmid != RM_XLOG_ID)
532
RecPtr.xrecoff = SizeOfXLogLongPHD; /* start of 1st chkpt
538
* Here we scan the rdata list, determine which buffers must be backed
539
* up, and compute the CRC values for the data. Note that the record
540
* header isn't added into the CRC yet since we don't know the final
541
* length or info bits quite yet.
543
* We may have to loop back to here if a race condition is detected
544
* below. We could prevent the race by doing all this work while
545
* holding the insert lock, but it seems better to avoid doing CRC
546
* calculations while holding the lock. This means we have to be
547
* careful about modifying the rdata list until we know we aren't
548
* going to loop back again. The only change we allow ourselves to
549
* make earlier is to set rdt->data = NULL in list items we have
550
* decided we will have to back up the whole buffer for. This is OK
551
* because we will certainly decide the same thing again for those
552
* items if we do it over; doing it here saves an extra pass over the
556
for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++)
558
dtbuf[i] = InvalidBuffer;
559
dtbuf_bkp[i] = false;
562
INIT_CRC64(rdata_crc);
566
if (rdt->buffer == InvalidBuffer)
568
/* Simple data, just include it */
570
COMP_CRC64(rdata_crc, rdt->data, rdt->len);
574
/* Find info for buffer */
575
for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++)
577
if (rdt->buffer == dtbuf[i])
579
/* Buffer already referenced by earlier list item */
585
COMP_CRC64(rdata_crc, rdt->data, rdt->len);
589
if (dtbuf[i] == InvalidBuffer)
591
/* OK, put it in this slot */
592
dtbuf[i] = rdt->buffer;
595
* XXX We assume page LSN is first data on page
597
dtbuf_lsn[i] = *((XLogRecPtr *) BufferGetBlock(rdt->buffer));
598
if (XLByteLE(dtbuf_lsn[i], RedoRecPtr))
606
BufferGetBlock(dtbuf[i]),
608
dtbuf_xlg[i].node = BufferGetFileNode(dtbuf[i]);
609
dtbuf_xlg[i].block = BufferGetBlockNumber(dtbuf[i]);
611
(char *) &(dtbuf_xlg[i]) + sizeof(crc64),
612
sizeof(BkpBlock) - sizeof(crc64));
614
dtbuf_xlg[i].crc = dtcrc;
619
COMP_CRC64(rdata_crc, rdt->data, rdt->len);
624
if (i >= XLR_MAX_BKP_BLOCKS)
625
elog(PANIC, "can backup at most %d blocks per xlog record",
628
/* Break out of loop when rdt points to last list item */
629
if (rdt->next == NULL)
635
* NOTE: the test for len == 0 here is somewhat fishy, since in theory
636
* all of the rmgr data might have been suppressed in favor of backup
637
* blocks. Currently, all callers of XLogInsert provide at least some
638
* not-in-a-buffer data and so len == 0 should never happen, but that
639
* may not be true forever. If you need to remove the len == 0 check,
640
* also remove the check for xl_len == 0 in ReadRecord, below.
643
elog(PANIC, "invalid xlog record length %u", len);
645
START_CRIT_SECTION();
647
/* update LogwrtResult before doing cache fill check */
649
/* use volatile pointer to prevent code rearrangement */
650
volatile XLogCtlData *xlogctl = XLogCtl;
652
SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
653
LogwrtRqst = xlogctl->LogwrtRqst;
654
LogwrtResult = xlogctl->LogwrtResult;
655
SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
659
* If cache is half filled then try to acquire write lock and do
660
* XLogWrite. Ignore any fractional blocks in performing this check.
662
LogwrtRqst.Write.xrecoff -= LogwrtRqst.Write.xrecoff % BLCKSZ;
663
if (LogwrtRqst.Write.xlogid != LogwrtResult.Write.xlogid ||
664
(LogwrtRqst.Write.xrecoff >= LogwrtResult.Write.xrecoff +
665
XLogCtl->XLogCacheByte / 2))
667
if (LWLockConditionalAcquire(WALWriteLock, LW_EXCLUSIVE))
669
LogwrtResult = XLogCtl->Write.LogwrtResult;
670
if (XLByteLT(LogwrtResult.Write, LogwrtRqst.Write))
671
XLogWrite(LogwrtRqst);
672
LWLockRelease(WALWriteLock);
676
/* Now wait to get insert lock */
677
LWLockAcquire(WALInsertLock, LW_EXCLUSIVE);
680
* Check to see if my RedoRecPtr is out of date. If so, may have to
681
* go back and recompute everything. This can only happen just after
682
* a checkpoint, so it's better to be slow in this case and fast
685
if (!XLByteEQ(RedoRecPtr, Insert->RedoRecPtr))
687
Assert(XLByteLT(RedoRecPtr, Insert->RedoRecPtr));
688
RedoRecPtr = Insert->RedoRecPtr;
690
for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++)
692
if (dtbuf[i] == InvalidBuffer)
694
if (dtbuf_bkp[i] == false &&
695
XLByteLE(dtbuf_lsn[i], RedoRecPtr))
698
* Oops, this buffer now needs to be backed up, but we
699
* didn't think so above. Start over.
701
LWLockRelease(WALInsertLock);
709
* Make additional rdata list entries for the backup blocks, so that
710
* we don't need to special-case them in the write loop. Note that we
711
* have now irrevocably changed the input rdata list. At the exit of
712
* this loop, write_len includes the backup block data.
714
* Also set the appropriate info bits to show which buffers were backed
715
* up. The i'th XLR_SET_BKP_BLOCK bit corresponds to the i'th
716
* distinct buffer value (ignoring InvalidBuffer) appearing in the
720
for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++)
722
if (dtbuf[i] == InvalidBuffer || !(dtbuf_bkp[i]))
725
info |= XLR_SET_BKP_BLOCK(i);
727
rdt->next = &(dtbuf_rdt[2 * i]);
729
dtbuf_rdt[2 * i].data = (char *) &(dtbuf_xlg[i]);
730
dtbuf_rdt[2 * i].len = sizeof(BkpBlock);
731
write_len += sizeof(BkpBlock);
733
rdt = dtbuf_rdt[2 * i].next = &(dtbuf_rdt[2 * i + 1]);
735
dtbuf_rdt[2 * i + 1].data = (char *) BufferGetBlock(dtbuf[i]);
736
dtbuf_rdt[2 * i + 1].len = BLCKSZ;
738
dtbuf_rdt[2 * i + 1].next = NULL;
742
* If there isn't enough space on the current XLOG page for a record
743
* header, advance to the next page (leaving the unused space as
747
freespace = INSERT_FREESPACE(Insert);
748
if (freespace < SizeOfXLogRecord)
750
updrqst = AdvanceXLInsertBuffer();
751
freespace = INSERT_FREESPACE(Insert);
754
curridx = Insert->curridx;
755
record = (XLogRecord *) Insert->currpos;
757
/* Insert record header */
759
record->xl_prev = Insert->PrevRecord;
760
record->xl_xid = GetCurrentTransactionIdIfAny();
761
record->xl_len = len; /* doesn't include backup blocks */
762
record->xl_info = info;
763
record->xl_rmid = rmid;
765
/* Now we can finish computing the main CRC */
766
COMP_CRC64(rdata_crc, (char *) record + sizeof(crc64),
767
SizeOfXLogRecord - sizeof(crc64));
768
FIN_CRC64(rdata_crc);
769
record->xl_crc = rdata_crc;
771
/* Compute record's XLOG location */
772
INSERT_RECPTR(RecPtr, Insert, curridx);
774
/* If first XLOG record of transaction, save it in PGPROC array */
775
if (MyLastRecPtr.xrecoff == 0 && !no_tran)
778
* We do not acquire SInvalLock here because of possible deadlock.
779
* Anyone who wants to inspect other procs' logRec must acquire
780
* WALInsertLock, instead. A better solution would be a per-PROC
781
* spinlock, but no time for that before 7.2 --- tgl 12/19/01.
783
MyProc->logRec = RecPtr;
791
sprintf(buf, "INSERT @ %X/%X: ", RecPtr.xlogid, RecPtr.xrecoff);
792
xlog_outrec(buf, record);
793
if (rdata->data != NULL)
796
RmgrTable[record->xl_rmid].rm_desc(buf, record->xl_info, rdata->data);
798
elog(LOG, "%s", buf);
802
/* Record begin of record in appropriate places */
804
MyLastRecPtr = RecPtr;
805
ProcLastRecPtr = RecPtr;
806
Insert->PrevRecord = RecPtr;
807
MyXactMadeXLogEntry = true;
809
Insert->currpos += SizeOfXLogRecord;
810
freespace -= SizeOfXLogRecord;
813
* Append the data, including backup blocks if any
817
while (rdata->data == NULL)
822
if (rdata->len > freespace)
824
memcpy(Insert->currpos, rdata->data, freespace);
825
rdata->data += freespace;
826
rdata->len -= freespace;
827
write_len -= freespace;
831
memcpy(Insert->currpos, rdata->data, rdata->len);
832
freespace -= rdata->len;
833
write_len -= rdata->len;
834
Insert->currpos += rdata->len;
840
/* Use next buffer */
841
updrqst = AdvanceXLInsertBuffer();
842
curridx = Insert->curridx;
843
/* Insert cont-record header */
844
Insert->currpage->xlp_info |= XLP_FIRST_IS_CONTRECORD;
845
contrecord = (XLogContRecord *) Insert->currpos;
846
contrecord->xl_rem_len = write_len;
847
Insert->currpos += SizeOfXLogContRecord;
848
freespace = INSERT_FREESPACE(Insert);
851
/* Ensure next record will be properly aligned */
852
Insert->currpos = (char *) Insert->currpage +
853
MAXALIGN(Insert->currpos - (char *) Insert->currpage);
854
freespace = INSERT_FREESPACE(Insert);
857
* The recptr I return is the beginning of the *next* record. This
858
* will be stored as LSN for changed data pages...
860
INSERT_RECPTR(RecPtr, Insert, curridx);
862
/* Need to update shared LogwrtRqst if some block was filled up */
863
if (freespace < SizeOfXLogRecord)
864
updrqst = true; /* curridx is filled and available for
867
curridx = PrevBufIdx(curridx);
868
WriteRqst = XLogCtl->xlblocks[curridx];
870
LWLockRelease(WALInsertLock);
874
/* use volatile pointer to prevent code rearrangement */
875
volatile XLogCtlData *xlogctl = XLogCtl;
877
SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
878
/* advance global request to include new block(s) */
879
if (XLByteLT(xlogctl->LogwrtRqst.Write, WriteRqst))
880
xlogctl->LogwrtRqst.Write = WriteRqst;
881
/* update local result copy while I have the chance */
882
LogwrtResult = xlogctl->LogwrtResult;
883
SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
886
ProcLastRecEnd = RecPtr;
896
* Create an archive notification file
898
* The name of the notification file is the message that will be picked up
899
* by the archiver, e.g. we write 0000000100000001000000C6.ready
900
* and the archiver then knows to archive XLogDir/0000000100000001000000C6,
901
* then when complete, rename it to 0000000100000001000000C6.done
904
XLogArchiveNotify(const char *xlog)
906
char archiveStatusPath[MAXPGPATH];
909
/* insert an otherwise empty file called <XLOG>.ready */
910
StatusFilePath(archiveStatusPath, xlog, ".ready");
911
fd = AllocateFile(archiveStatusPath, "w");
915
(errcode_for_file_access(),
916
errmsg("could not create archive status file \"%s\": %m",
917
archiveStatusPath)));
923
(errcode_for_file_access(),
924
errmsg("could not write archive status file \"%s\": %m",
925
archiveStatusPath)));
929
/* Notify archiver that it's got something to do */
930
if (IsUnderPostmaster)
931
SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
935
* Convenience routine to notify using log/seg representation of filename
938
XLogArchiveNotifySeg(uint32 log, uint32 seg)
940
char xlog[MAXFNAMELEN];
942
XLogFileName(xlog, ThisTimeLineID, log, seg);
943
XLogArchiveNotify(xlog);
949
* Checks for a ".done" archive notification file. This is called when we
950
* are ready to delete or recycle an old XLOG segment file. If it is okay
951
* to delete it then return true.
953
* If <XLOG>.done exists, then return true; else if <XLOG>.ready exists,
954
* then return false; else create <XLOG>.ready and return false. The
955
* last case covers the possibility that the original attempt to create
956
* <XLOG>.ready failed.
959
XLogArchiveIsDone(const char *xlog)
961
char archiveStatusPath[MAXPGPATH];
962
struct stat stat_buf;
964
/* First check for .done --- this is the expected case */
965
StatusFilePath(archiveStatusPath, xlog, ".done");
966
if (stat(archiveStatusPath, &stat_buf) == 0)
969
/* check for .ready --- this means archiver is still busy with it */
970
StatusFilePath(archiveStatusPath, xlog, ".ready");
971
if (stat(archiveStatusPath, &stat_buf) == 0)
974
/* Race condition --- maybe archiver just finished, so recheck */
975
StatusFilePath(archiveStatusPath, xlog, ".done");
976
if (stat(archiveStatusPath, &stat_buf) == 0)
979
/* Retry creation of the .ready file */
980
XLogArchiveNotify(xlog);
987
* Cleanup archive notification file(s) for a particular xlog segment
990
XLogArchiveCleanup(const char *xlog)
992
char archiveStatusPath[MAXPGPATH];
994
/* Remove the .done file */
995
StatusFilePath(archiveStatusPath, xlog, ".done");
996
unlink(archiveStatusPath);
997
/* should we complain about failure? */
999
/* Remove the .ready file if present --- normally it shouldn't be */
1000
StatusFilePath(archiveStatusPath, xlog, ".ready");
1001
unlink(archiveStatusPath);
1002
/* should we complain about failure? */
1006
* Advance the Insert state to the next buffer page, writing out the next
1007
* buffer if it still contains unwritten data.
1009
* The global LogwrtRqst.Write pointer needs to be advanced to include the
1010
* just-filled page. If we can do this for free (without an extra lock),
1011
* we do so here. Otherwise the caller must do it. We return TRUE if the
1012
* request update still needs to be done, FALSE if we did it internally.
1014
* Must be called with WALInsertLock held.
1017
AdvanceXLInsertBuffer(void)
1019
XLogCtlInsert *Insert = &XLogCtl->Insert;
1020
XLogCtlWrite *Write = &XLogCtl->Write;
1021
uint16 nextidx = NextBufIdx(Insert->curridx);
1022
bool update_needed = true;
1023
XLogRecPtr OldPageRqstPtr;
1024
XLogwrtRqst WriteRqst;
1025
XLogRecPtr NewPageEndPtr;
1026
XLogPageHeader NewPage;
1028
/* Use Insert->LogwrtResult copy if it's more fresh */
1029
if (XLByteLT(LogwrtResult.Write, Insert->LogwrtResult.Write))
1030
LogwrtResult = Insert->LogwrtResult;
1033
* Get ending-offset of the buffer page we need to replace (this may
1034
* be zero if the buffer hasn't been used yet). Fall through if it's
1035
* already written out.
1037
OldPageRqstPtr = XLogCtl->xlblocks[nextidx];
1038
if (!XLByteLE(OldPageRqstPtr, LogwrtResult.Write))
1040
/* nope, got work to do... */
1041
XLogRecPtr FinishedPageRqstPtr;
1043
FinishedPageRqstPtr = XLogCtl->xlblocks[Insert->curridx];
1045
/* Before waiting, get info_lck and update LogwrtResult */
1047
/* use volatile pointer to prevent code rearrangement */
1048
volatile XLogCtlData *xlogctl = XLogCtl;
1050
SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
1051
if (XLByteLT(xlogctl->LogwrtRqst.Write, FinishedPageRqstPtr))
1052
xlogctl->LogwrtRqst.Write = FinishedPageRqstPtr;
1053
LogwrtResult = xlogctl->LogwrtResult;
1054
SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
1057
update_needed = false; /* Did the shared-request update */
1059
if (XLByteLE(OldPageRqstPtr, LogwrtResult.Write))
1061
/* OK, someone wrote it already */
1062
Insert->LogwrtResult = LogwrtResult;
1066
/* Must acquire write lock */
1067
LWLockAcquire(WALWriteLock, LW_EXCLUSIVE);
1068
LogwrtResult = Write->LogwrtResult;
1069
if (XLByteLE(OldPageRqstPtr, LogwrtResult.Write))
1071
/* OK, someone wrote it already */
1072
LWLockRelease(WALWriteLock);
1073
Insert->LogwrtResult = LogwrtResult;
1078
* Have to write buffers while holding insert lock. This
1079
* is not good, so only write as much as we absolutely
1082
WriteRqst.Write = OldPageRqstPtr;
1083
WriteRqst.Flush.xlogid = 0;
1084
WriteRqst.Flush.xrecoff = 0;
1085
XLogWrite(WriteRqst);
1086
LWLockRelease(WALWriteLock);
1087
Insert->LogwrtResult = LogwrtResult;
1093
* Now the next buffer slot is free and we can set it up to be the
1096
NewPageEndPtr = XLogCtl->xlblocks[Insert->curridx];
1097
if (NewPageEndPtr.xrecoff >= XLogFileSize)
1099
/* crossing a logid boundary */
1100
NewPageEndPtr.xlogid += 1;
1101
NewPageEndPtr.xrecoff = BLCKSZ;
1104
NewPageEndPtr.xrecoff += BLCKSZ;
1105
XLogCtl->xlblocks[nextidx] = NewPageEndPtr;
1106
NewPage = (XLogPageHeader) (XLogCtl->pages + nextidx * BLCKSZ);
1107
Insert->curridx = nextidx;
1108
Insert->currpage = NewPage;
1109
Insert->currpos = ((char *) NewPage) + SizeOfXLogShortPHD;
1112
* Be sure to re-zero the buffer so that bytes beyond what we've
1113
* written will look like zeroes and not valid XLOG records...
1115
MemSet((char *) NewPage, 0, BLCKSZ);
1118
* Fill the new page's header
1120
NewPage->xlp_magic = XLOG_PAGE_MAGIC;
1121
/* NewPage->xlp_info = 0; */ /* done by memset */
1122
NewPage->xlp_tli = ThisTimeLineID;
1123
NewPage->xlp_pageaddr.xlogid = NewPageEndPtr.xlogid;
1124
NewPage->xlp_pageaddr.xrecoff = NewPageEndPtr.xrecoff - BLCKSZ;
1127
* If first page of an XLOG segment file, make it a long header.
1129
if ((NewPage->xlp_pageaddr.xrecoff % XLogSegSize) == 0)
1131
XLogLongPageHeader NewLongPage = (XLogLongPageHeader) NewPage;
1133
NewLongPage->xlp_sysid = ControlFile->system_identifier;
1134
NewLongPage->xlp_seg_size = XLogSegSize;
1135
NewPage->xlp_info |= XLP_LONG_HEADER;
1136
Insert->currpos = ((char *) NewPage) + SizeOfXLogLongPHD;
1139
return update_needed;
1143
* Write and/or fsync the log at least as far as WriteRqst indicates.
1145
* Must be called with WALWriteLock held.
1148
XLogWrite(XLogwrtRqst WriteRqst)
1150
XLogCtlWrite *Write = &XLogCtl->Write;
1156
* Update local LogwrtResult (caller probably did this already,
1159
LogwrtResult = Write->LogwrtResult;
1161
while (XLByteLT(LogwrtResult.Write, WriteRqst.Write))
1164
* Make sure we're not ahead of the insert process. This could
1165
* happen if we're passed a bogus WriteRqst.Write that is past the
1166
* end of the last page that's been initialized by
1167
* AdvanceXLInsertBuffer.
1169
if (!XLByteLT(LogwrtResult.Write, XLogCtl->xlblocks[Write->curridx]))
1170
elog(PANIC, "xlog write request %X/%X is past end of log %X/%X",
1171
LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff,
1172
XLogCtl->xlblocks[Write->curridx].xlogid,
1173
XLogCtl->xlblocks[Write->curridx].xrecoff);
1175
/* Advance LogwrtResult.Write to end of current buffer page */
1176
LogwrtResult.Write = XLogCtl->xlblocks[Write->curridx];
1177
ispartialpage = XLByteLT(WriteRqst.Write, LogwrtResult.Write);
1179
if (!XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg))
1182
* Switch to new logfile segment.
1184
if (openLogFile >= 0)
1186
if (close(openLogFile))
1188
(errcode_for_file_access(),
1189
errmsg("could not close log file %u, segment %u: %m",
1190
openLogId, openLogSeg)));
1193
XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
1195
/* create/use new log file */
1196
use_existent = true;
1197
openLogFile = XLogFileInit(openLogId, openLogSeg,
1198
&use_existent, true);
1201
/* update pg_control, unless someone else already did */
1202
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
1203
if (ControlFile->logId < openLogId ||
1204
(ControlFile->logId == openLogId &&
1205
ControlFile->logSeg < openLogSeg + 1))
1207
ControlFile->logId = openLogId;
1208
ControlFile->logSeg = openLogSeg + 1;
1209
ControlFile->time = time(NULL);
1210
UpdateControlFile();
1213
* Signal bgwriter to start a checkpoint if it's been
1214
* too long since the last one. (We look at local copy of
1215
* RedoRecPtr which might be a little out of date, but
1216
* should be close enough for this purpose.)
1218
* A straight computation of segment number could overflow
1219
* 32 bits. Rather than assuming we have working 64-bit
1220
* arithmetic, we compare the highest-order bits separately,
1221
* and force a checkpoint immediately when they change.
1223
if (IsUnderPostmaster)
1227
uint32 old_highbits,
1230
old_segno = (RedoRecPtr.xlogid % XLogSegSize) * XLogSegsPerFile +
1231
(RedoRecPtr.xrecoff / XLogSegSize);
1232
old_highbits = RedoRecPtr.xlogid / XLogSegSize;
1233
new_segno = (openLogId % XLogSegSize) * XLogSegsPerFile +
1235
new_highbits = openLogId / XLogSegSize;
1236
if (new_highbits != old_highbits ||
1237
new_segno >= old_segno + (uint32) CheckPointSegments)
1241
elog(LOG, "time for a checkpoint, signaling bgwriter");
1243
RequestCheckpoint(false);
1247
LWLockRelease(ControlFileLock);
1250
if (openLogFile < 0)
1252
XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
1253
openLogFile = XLogFileOpen(openLogId, openLogSeg);
1257
/* Need to seek in the file? */
1258
if (openLogOff != (LogwrtResult.Write.xrecoff - BLCKSZ) % XLogSegSize)
1260
openLogOff = (LogwrtResult.Write.xrecoff - BLCKSZ) % XLogSegSize;
1261
if (lseek(openLogFile, (off_t) openLogOff, SEEK_SET) < 0)
1263
(errcode_for_file_access(),
1264
errmsg("could not seek in log file %u, segment %u to offset %u: %m",
1265
openLogId, openLogSeg, openLogOff)));
1268
/* OK to write the page */
1269
from = XLogCtl->pages + Write->curridx * BLCKSZ;
1271
if (write(openLogFile, from, BLCKSZ) != BLCKSZ)
1273
/* if write didn't set errno, assume problem is no disk space */
1277
(errcode_for_file_access(),
1278
errmsg("could not write to log file %u, segment %u at offset %u: %m",
1279
openLogId, openLogSeg, openLogOff)));
1281
openLogOff += BLCKSZ;
1284
* If we just wrote the whole last page of a logfile segment,
1285
* fsync the segment immediately. This avoids having to go back
1286
* and re-open prior segments when an fsync request comes along
1287
* later. Doing it here ensures that one and only one backend will
1288
* perform this fsync.
1290
* This is also the right place to notify the Archiver that the
1291
* segment is ready to copy to archival storage.
1293
if (openLogOff >= XLogSegSize && !ispartialpage)
1296
LogwrtResult.Flush = LogwrtResult.Write; /* end of current page */
1298
if (XLogArchivingActive())
1299
XLogArchiveNotifySeg(openLogId, openLogSeg);
1304
/* Only asked to write a partial page */
1305
LogwrtResult.Write = WriteRqst.Write;
1308
Write->curridx = NextBufIdx(Write->curridx);
1312
* If asked to flush, do so
1314
if (XLByteLT(LogwrtResult.Flush, WriteRqst.Flush) &&
1315
XLByteLT(LogwrtResult.Flush, LogwrtResult.Write))
1318
* Could get here without iterating above loop, in which case we
1319
* might have no open file or the wrong one. However, we do not
1320
* need to fsync more than one file.
1322
if (sync_method != SYNC_METHOD_OPEN)
1324
if (openLogFile >= 0 &&
1325
!XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg))
1327
if (close(openLogFile))
1329
(errcode_for_file_access(),
1330
errmsg("could not close log file %u, segment %u: %m",
1331
openLogId, openLogSeg)));
1334
if (openLogFile < 0)
1336
XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
1337
openLogFile = XLogFileOpen(openLogId, openLogSeg);
1342
LogwrtResult.Flush = LogwrtResult.Write;
1346
* Update shared-memory status
1348
* We make sure that the shared 'request' values do not fall behind the
1349
* 'result' values. This is not absolutely essential, but it saves
1350
* some code in a couple of places.
1353
/* use volatile pointer to prevent code rearrangement */
1354
volatile XLogCtlData *xlogctl = XLogCtl;
1356
SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
1357
xlogctl->LogwrtResult = LogwrtResult;
1358
if (XLByteLT(xlogctl->LogwrtRqst.Write, LogwrtResult.Write))
1359
xlogctl->LogwrtRqst.Write = LogwrtResult.Write;
1360
if (XLByteLT(xlogctl->LogwrtRqst.Flush, LogwrtResult.Flush))
1361
xlogctl->LogwrtRqst.Flush = LogwrtResult.Flush;
1362
SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
1365
Write->LogwrtResult = LogwrtResult;
1369
* Ensure that all XLOG data through the given position is flushed to disk.
1371
* NOTE: this differs from XLogWrite mainly in that the WALWriteLock is not
1372
* already held, and we try to avoid acquiring it if possible.
1375
XLogFlush(XLogRecPtr record)
1377
XLogRecPtr WriteRqstPtr;
1378
XLogwrtRqst WriteRqst;
1380
/* Disabled during REDO */
1384
/* Quick exit if already known flushed */
1385
if (XLByteLE(record, LogwrtResult.Flush))
1390
elog(LOG, "xlog flush request %X/%X; write %X/%X; flush %X/%X",
1391
record.xlogid, record.xrecoff,
1392
LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff,
1393
LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff);
1396
START_CRIT_SECTION();
1399
* Since fsync is usually a horribly expensive operation, we try to
1400
* piggyback as much data as we can on each fsync: if we see any more
1401
* data entered into the xlog buffer, we'll write and fsync that too,
1402
* so that the final value of LogwrtResult.Flush is as large as
1403
* possible. This gives us some chance of avoiding another fsync
1404
* immediately after.
1407
/* initialize to given target; may increase below */
1408
WriteRqstPtr = record;
1410
/* read LogwrtResult and update local state */
1412
/* use volatile pointer to prevent code rearrangement */
1413
volatile XLogCtlData *xlogctl = XLogCtl;
1415
SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
1416
if (XLByteLT(WriteRqstPtr, xlogctl->LogwrtRqst.Write))
1417
WriteRqstPtr = xlogctl->LogwrtRqst.Write;
1418
LogwrtResult = xlogctl->LogwrtResult;
1419
SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
1423
if (!XLByteLE(record, LogwrtResult.Flush))
1425
/* now wait for the write lock */
1426
LWLockAcquire(WALWriteLock, LW_EXCLUSIVE);
1427
LogwrtResult = XLogCtl->Write.LogwrtResult;
1428
if (!XLByteLE(record, LogwrtResult.Flush))
1430
/* try to write/flush later additions to XLOG as well */
1431
if (LWLockConditionalAcquire(WALInsertLock, LW_EXCLUSIVE))
1433
XLogCtlInsert *Insert = &XLogCtl->Insert;
1434
uint32 freespace = INSERT_FREESPACE(Insert);
1436
if (freespace < SizeOfXLogRecord) /* buffer is full */
1437
WriteRqstPtr = XLogCtl->xlblocks[Insert->curridx];
1440
WriteRqstPtr = XLogCtl->xlblocks[Insert->curridx];
1441
WriteRqstPtr.xrecoff -= freespace;
1443
LWLockRelease(WALInsertLock);
1444
WriteRqst.Write = WriteRqstPtr;
1445
WriteRqst.Flush = WriteRqstPtr;
1449
WriteRqst.Write = WriteRqstPtr;
1450
WriteRqst.Flush = record;
1452
XLogWrite(WriteRqst);
1454
LWLockRelease(WALWriteLock);
1460
* If we still haven't flushed to the request point then we have a
1461
* problem; most likely, the requested flush point is past end of
1462
* XLOG. This has been seen to occur when a disk page has a corrupted
1465
* Formerly we treated this as a PANIC condition, but that hurts the
1466
* system's robustness rather than helping it: we do not want to take
1467
* down the whole system due to corruption on one data page. In
1468
* particular, if the bad page is encountered again during recovery
1469
* then we would be unable to restart the database at all! (This
1470
* scenario has actually happened in the field several times with 7.1
1471
* releases. Note that we cannot get here while InRedo is true, but if
1472
* the bad page is brought in and marked dirty during recovery then
1473
* CreateCheckPoint will try to flush it at the end of recovery.)
1475
* The current approach is to ERROR under normal conditions, but only
1476
* WARNING during recovery, so that the system can be brought up even
1477
* if there's a corrupt LSN. Note that for calls from xact.c, the
1478
* ERROR will be promoted to PANIC since xact.c calls this routine
1479
* inside a critical section. However, calls from bufmgr.c are not
1480
* within critical sections and so we will not force a restart for a
1481
* bad LSN on a data page.
1483
if (XLByteLT(LogwrtResult.Flush, record))
1484
elog(InRecovery ? WARNING : ERROR,
1485
"xlog flush request %X/%X is not satisfied --- flushed only to %X/%X",
1486
record.xlogid, record.xrecoff,
1487
LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff);
1491
* Create a new XLOG file segment, or open a pre-existing one.
1493
* log, seg: identify segment to be created/opened.
1495
* *use_existent: if TRUE, OK to use a pre-existing file (else, any
1496
* pre-existing file will be deleted). On return, TRUE if a pre-existing
1499
* use_lock: if TRUE, acquire ControlFileLock while moving file into
1500
* place. This should be TRUE except during bootstrap log creation. The
1501
* caller must *not* hold the lock at call.
1503
* Returns FD of opened file.
1506
XLogFileInit(uint32 log, uint32 seg,
1507
bool *use_existent, bool use_lock)
1509
char path[MAXPGPATH];
1510
char tmppath[MAXPGPATH];
1511
char zbuffer[BLCKSZ];
1515
XLogFilePath(path, ThisTimeLineID, log, seg);
1518
* Try to use existent file (checkpoint maker may have created it
1523
fd = BasicOpenFile(path, O_RDWR | PG_BINARY | XLOG_SYNC_BIT,
1527
if (errno != ENOENT)
1529
(errcode_for_file_access(),
1530
errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
1538
* Initialize an empty (all zeroes) segment. NOTE: it is possible
1539
* that another process is doing the same thing. If so, we will end
1540
* up pre-creating an extra log segment. That seems OK, and better
1541
* than holding the lock throughout this lengthy process.
1543
snprintf(tmppath, MAXPGPATH, "%s/xlogtemp.%d", XLogDir, (int)getpid());
1547
/* do not use XLOG_SYNC_BIT here --- want to fsync only at end of fill */
1548
fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
1552
(errcode_for_file_access(),
1553
errmsg("could not create file \"%s\": %m", tmppath)));
1556
* Zero-fill the file. We have to do this the hard way to ensure that
1557
* all the file space has really been allocated --- on platforms that
1558
* allow "holes" in files, just seeking to the end doesn't allocate
1559
* intermediate space. This way, we know that we have all the space
1560
* and (after the fsync below) that all the indirect blocks are down
1561
* on disk. Therefore, fdatasync(2) or O_DSYNC will be sufficient to
1562
* sync future writes to the log file.
1564
MemSet(zbuffer, 0, sizeof(zbuffer));
1565
for (nbytes = 0; nbytes < XLogSegSize; nbytes += sizeof(zbuffer))
1568
if ((int) write(fd, zbuffer, sizeof(zbuffer)) != (int) sizeof(zbuffer))
1570
int save_errno = errno;
1573
* If we fail to make the file, delete it to release disk
1577
/* if write didn't set errno, assume problem is no disk space */
1578
errno = save_errno ? save_errno : ENOSPC;
1581
(errcode_for_file_access(),
1582
errmsg("could not write to file \"%s\": %m", tmppath)));
1586
if (pg_fsync(fd) != 0)
1588
(errcode_for_file_access(),
1589
errmsg("could not fsync file \"%s\": %m", tmppath)));
1593
(errcode_for_file_access(),
1594
errmsg("could not close file \"%s\": %m", tmppath)));
1597
* Now move the segment into place with its final name.
1599
* If caller didn't want to use a pre-existing file, get rid of any
1600
* pre-existing file. Otherwise, cope with possibility that someone
1601
* else has created the file while we were filling ours: if so, use
1602
* ours to pre-create a future log segment.
1604
if (!InstallXLogFileSegment(log, seg, tmppath,
1605
*use_existent, XLOGfileslop,
1608
/* No need for any more future segments... */
1612
/* Set flag to tell caller there was no existent file */
1613
*use_existent = false;
1615
/* Now open original target segment (might not be file I just made) */
1616
fd = BasicOpenFile(path, O_RDWR | PG_BINARY | XLOG_SYNC_BIT,
1620
(errcode_for_file_access(),
1621
errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
1628
* Create a new XLOG file segment by copying a pre-existing one.
1630
* log, seg: identify segment to be created.
1632
* srcTLI, srclog, srcseg: identify segment to be copied (could be from
1633
* a different timeline)
1635
* Currently this is only used during recovery, and so there are no locking
1636
* considerations. But we should be just as tense as XLogFileInit to avoid
1637
* emplacing a bogus file.
1640
XLogFileCopy(uint32 log, uint32 seg,
1641
TimeLineID srcTLI, uint32 srclog, uint32 srcseg)
1643
char path[MAXPGPATH];
1644
char tmppath[MAXPGPATH];
1645
char buffer[BLCKSZ];
1651
* Open the source file
1653
XLogFilePath(path, srcTLI, srclog, srcseg);
1654
srcfd = BasicOpenFile(path, O_RDONLY | PG_BINARY, 0);
1657
(errcode_for_file_access(),
1658
errmsg("could not open file \"%s\": %m", path)));
1661
* Copy into a temp file name.
1663
snprintf(tmppath, MAXPGPATH, "%s/xlogtemp.%d", XLogDir, (int)getpid());
1667
/* do not use XLOG_SYNC_BIT here --- want to fsync only at end of fill */
1668
fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
1672
(errcode_for_file_access(),
1673
errmsg("could not create file \"%s\": %m", tmppath)));
1676
* Do the data copying.
1678
for (nbytes = 0; nbytes < XLogSegSize; nbytes += sizeof(buffer))
1681
if ((int) read(srcfd, buffer, sizeof(buffer)) != (int) sizeof(buffer))
1685
(errcode_for_file_access(),
1686
errmsg("could not read file \"%s\": %m", path)));
1689
(errmsg("not enough data in file \"%s\"", path)));
1692
if ((int) write(fd, buffer, sizeof(buffer)) != (int) sizeof(buffer))
1694
int save_errno = errno;
1697
* If we fail to make the file, delete it to release disk
1701
/* if write didn't set errno, assume problem is no disk space */
1702
errno = save_errno ? save_errno : ENOSPC;
1705
(errcode_for_file_access(),
1706
errmsg("could not write to file \"%s\": %m", tmppath)));
1710
if (pg_fsync(fd) != 0)
1712
(errcode_for_file_access(),
1713
errmsg("could not fsync file \"%s\": %m", tmppath)));
1717
(errcode_for_file_access(),
1718
errmsg("could not close file \"%s\": %m", tmppath)));
1723
* Now move the segment into place with its final name.
1725
if (!InstallXLogFileSegment(log, seg, tmppath, false, 0, false))
1726
elog(PANIC, "InstallXLogFileSegment should not have failed");
1730
* Install a new XLOG segment file as a current or future log segment.
1732
* This is used both to install a newly-created segment (which has a temp
1733
* filename while it's being created) and to recycle an old segment.
1735
* log, seg: identify segment to install as (or first possible target).
1737
* tmppath: initial name of file to install. It will be renamed into place.
1739
* find_free: if TRUE, install the new segment at the first empty log/seg
1740
* number at or after the passed numbers. If FALSE, install the new segment
1741
* exactly where specified, deleting any existing segment file there.
1743
* max_advance: maximum number of log/seg slots to advance past the starting
1744
* point. Fail if no free slot is found in this range. (Irrelevant if
1745
* find_free is FALSE.)
1747
* use_lock: if TRUE, acquire ControlFileLock while moving file into
1748
* place. This should be TRUE except during bootstrap log creation. The
1749
* caller must *not* hold the lock at call.
1751
* Returns TRUE if file installed, FALSE if not installed because of
1752
* exceeding max_advance limit. (Any other kind of failure causes ereport().)
1755
InstallXLogFileSegment(uint32 log, uint32 seg, char *tmppath,
1756
bool find_free, int max_advance,
1759
char path[MAXPGPATH];
1760
struct stat stat_buf;
1762
XLogFilePath(path, ThisTimeLineID, log, seg);
1765
* We want to be sure that only one process does this at a time.
1768
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
1772
/* Force installation: get rid of any pre-existing segment file */
1777
/* Find a free slot to put it in */
1778
while (stat(path, &stat_buf) == 0)
1780
if (--max_advance < 0)
1782
/* Failed to find a free slot within specified range */
1784
LWLockRelease(ControlFileLock);
1787
NextLogSeg(log, seg);
1788
XLogFilePath(path, ThisTimeLineID, log, seg);
1793
* Prefer link() to rename() here just to be really sure that we don't
1794
* overwrite an existing logfile. However, there shouldn't be one, so
1795
* rename() is an acceptable substitute except for the truly paranoid.
1797
#if HAVE_WORKING_LINK
1798
if (link(tmppath, path) < 0)
1800
(errcode_for_file_access(),
1801
errmsg("could not link file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m",
1802
tmppath, path, log, seg)));
1805
if (rename(tmppath, path) < 0)
1807
(errcode_for_file_access(),
1808
errmsg("could not rename file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m",
1809
tmppath, path, log, seg)));
1813
LWLockRelease(ControlFileLock);
1819
* Open a pre-existing logfile segment for writing.
1822
XLogFileOpen(uint32 log, uint32 seg)
1824
char path[MAXPGPATH];
1827
XLogFilePath(path, ThisTimeLineID, log, seg);
1829
fd = BasicOpenFile(path, O_RDWR | PG_BINARY | XLOG_SYNC_BIT,
1833
(errcode_for_file_access(),
1834
errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
1841
* Open a logfile segment for reading (during recovery).
1844
XLogFileRead(uint32 log, uint32 seg, int emode)
1846
char path[MAXPGPATH];
1847
char xlogfname[MAXFNAMELEN];
1852
* Loop looking for a suitable timeline ID: we might need to read any
1853
* of the timelines listed in expectedTLIs.
1855
* We expect curFileTLI on entry to be the TLI of the preceding file in
1856
* sequence, or 0 if there was no predecessor. We do not allow
1857
* curFileTLI to go backwards; this prevents us from picking up the
1858
* wrong file when a parent timeline extends to higher segment numbers
1859
* than the child we want to read.
1861
foreach(cell, expectedTLIs)
1863
TimeLineID tli = (TimeLineID) lfirst_int(cell);
1865
if (tli < curFileTLI)
1866
break; /* don't bother looking at too-old TLIs */
1868
if (InArchiveRecovery)
1870
XLogFileName(xlogfname, tli, log, seg);
1871
restoredFromArchive = RestoreArchivedFile(path, xlogfname,
1876
XLogFilePath(path, tli, log, seg);
1878
fd = BasicOpenFile(path, O_RDONLY | PG_BINARY, 0);
1885
if (errno != ENOENT) /* unexpected failure? */
1887
(errcode_for_file_access(),
1888
errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
1892
/* Couldn't find it. For simplicity, complain about front timeline */
1893
XLogFilePath(path, recoveryTargetTLI, log, seg);
1896
(errcode_for_file_access(),
1897
errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
1903
* Attempt to retrieve the specified file from off-line archival storage.
1904
* If successful, fill "path" with its complete path (note that this will be
1905
* a temp file name that doesn't follow the normal naming convention), and
1908
* If not successful, fill "path" with the name of the normal on-line file
1909
* (which may or may not actually exist, but we'll try to use it), and return
1912
* For fixed-size files, the caller may pass the expected size as an
1913
* additional crosscheck on successful recovery. If the file size is not
1914
* known, set expectedSize = 0.
1917
RestoreArchivedFile(char *path, const char *xlogfname,
1918
const char *recovername, off_t expectedSize)
1920
char xlogpath[MAXPGPATH];
1921
char xlogRestoreCmd[MAXPGPATH];
1926
struct stat stat_buf;
1929
* When doing archive recovery, we always prefer an archived log file
1930
* even if a file of the same name exists in XLogDir. The reason is
1931
* that the file in XLogDir could be an old, un-filled or
1932
* partly-filled version that was copied and restored as part of
1933
* backing up $PGDATA.
1935
* We could try to optimize this slightly by checking the local copy
1936
* lastchange timestamp against the archived copy, but we have no API
1937
* to do this, nor can we guarantee that the lastchange timestamp was
1938
* preserved correctly when we copied to archive. Our aim is
1939
* robustness, so we elect not to do this.
1941
* If we cannot obtain the log file from the archive, however, we will
1942
* try to use the XLogDir file if it exists. This is so that we can
1943
* make use of log segments that weren't yet transferred to the
1946
* Notice that we don't actually overwrite any files when we copy back
1947
* from archive because the recoveryRestoreCommand may inadvertently
1948
* restore inappropriate xlogs, or they may be corrupt, so we may wish
1949
* to fallback to the segments remaining in current XLogDir later. The
1950
* copy-from-archive filename is always the same, ensuring that we
1951
* don't run out of disk space on long recoveries.
1953
snprintf(xlogpath, MAXPGPATH, "%s/%s", XLogDir, recovername);
1956
* Make sure there is no existing file named recovername.
1958
if (stat(xlogpath, &stat_buf) != 0)
1960
if (errno != ENOENT)
1962
(errcode_for_file_access(),
1963
errmsg("could not stat file \"%s\": %m",
1968
if (unlink(xlogpath) != 0)
1970
(errcode_for_file_access(),
1971
errmsg("could not remove file \"%s\": %m",
1976
* construct the command to be executed
1978
dp = xlogRestoreCmd;
1979
endp = xlogRestoreCmd + MAXPGPATH - 1;
1982
for (sp = recoveryRestoreCommand; *sp; sp++)
1989
/* %p: full path of target file */
1991
StrNCpy(dp, xlogpath, endp - dp);
1992
make_native_path(dp);
1996
/* %f: filename of desired file */
1998
StrNCpy(dp, xlogfname, endp - dp);
2002
/* convert %% to a single % */
2008
/* otherwise treat the % as not special */
2023
(errmsg_internal("executing restore command \"%s\"",
2027
* Copy xlog from archival storage to XLogDir
2029
rc = system(xlogRestoreCmd);
2033
* command apparently succeeded, but let's make sure the file is
2034
* really there now and has the correct size.
2036
* XXX I made wrong-size a fatal error to ensure the DBA would notice
2037
* it, but is that too strong? We could try to plow ahead with a
2038
* local copy of the file ... but the problem is that there
2039
* probably isn't one, and we'd incorrectly conclude we've reached
2040
* the end of WAL and we're done recovering ...
2042
if (stat(xlogpath, &stat_buf) == 0)
2044
if (expectedSize > 0 && stat_buf.st_size != expectedSize)
2046
(errmsg("archive file \"%s\" has wrong size: %lu instead of %lu",
2048
(unsigned long) stat_buf.st_size,
2049
(unsigned long) expectedSize)));
2053
(errmsg("restored log file \"%s\" from archive",
2055
strcpy(path, xlogpath);
2062
if (errno != ENOENT)
2064
(errcode_for_file_access(),
2065
errmsg("could not stat file \"%s\": %m",
2071
* remember, we rollforward UNTIL the restore fails so failure here is
2072
* just part of the process... that makes it difficult to determine
2073
* whether the restore failed because there isn't an archive to
2074
* restore, or because the administrator has specified the restore
2075
* program incorrectly. We have to assume the former.
2078
(errmsg("could not restore file \"%s\" from archive: return code %d",
2082
* if an archived file is not available, there might still be a
2083
* version of this file in XLogDir, so return that as the filename to
2086
* In many recovery scenarios we expect this to fail also, but if so that
2087
* just means we've reached the end of WAL.
2089
snprintf(path, MAXPGPATH, "%s/%s", XLogDir, xlogfname);
2094
* Preallocate log files beyond the specified log endpoint, according to
2095
* the XLOGfile user parameter.
2098
PreallocXlogFiles(XLogRecPtr endptr)
2106
XLByteToPrevSeg(endptr, _logId, _logSeg);
2107
if ((endptr.xrecoff - 1) % XLogSegSize >=
2108
(uint32) (0.75 * XLogSegSize))
2110
NextLogSeg(_logId, _logSeg);
2111
use_existent = true;
2112
lf = XLogFileInit(_logId, _logSeg, &use_existent, true);
2121
* Remove or move offline all log files older or equal to passed log/seg#
2123
* endptr is current (or recent) end of xlog; this is used to determine
2124
* whether we want to recycle rather than delete no-longer-wanted log files.
2127
MoveOfflineLogs(uint32 log, uint32 seg, XLogRecPtr endptr,
2128
int *nsegsremoved, int *nsegsrecycled)
2133
struct dirent *xlde;
2134
char lastoff[MAXFNAMELEN];
2135
char path[MAXPGPATH];
2140
XLByteToPrevSeg(endptr, endlogId, endlogSeg);
2142
xldir = AllocateDir(XLogDir);
2145
(errcode_for_file_access(),
2146
errmsg("could not open transaction log directory \"%s\": %m",
2149
XLogFileName(lastoff, ThisTimeLineID, log, seg);
2152
while ((xlde = readdir(xldir)) != NULL)
2155
* We ignore the timeline part of the XLOG segment identifiers in
2156
* deciding whether a segment is still needed. This ensures that
2157
* we won't prematurely remove a segment from a parent timeline.
2158
* We could probably be a little more proactive about removing
2159
* segments of non-parent timelines, but that would be a whole lot
2162
* We use the alphanumeric sorting property of the filenames to
2163
* decide which ones are earlier than the lastoff segment.
2165
if (strlen(xlde->d_name) == 24 &&
2166
strspn(xlde->d_name, "0123456789ABCDEF") == 24 &&
2167
strcmp(xlde->d_name + 8, lastoff + 8) <= 0)
2171
if (XLogArchivingActive())
2172
recycle = XLogArchiveIsDone(xlde->d_name);
2178
snprintf(path, MAXPGPATH, "%s/%s", XLogDir, xlde->d_name);
2181
* Before deleting the file, see if it can be recycled as
2182
* a future log segment. We allow recycling segments up
2183
* to XLOGfileslop segments beyond the current XLOG
2186
if (InstallXLogFileSegment(endlogId, endlogSeg, path,
2191
(errmsg("recycled transaction log file \"%s\"",
2197
/* No need for any more future segments... */
2199
(errmsg("removing transaction log file \"%s\"",
2205
XLogArchiveCleanup(xlde->d_name);
2213
* This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but
2214
* not in released version
2216
if (GetLastError() == ERROR_NO_MORE_FILES)
2221
(errcode_for_file_access(),
2222
errmsg("could not read transaction log directory \"%s\": %m",
2228
* Restore the backup blocks present in an XLOG record, if any.
2230
* We assume all of the record has been read into memory at *record.
2232
* Note: when a backup block is available in XLOG, we restore it
2233
* unconditionally, even if the page in the database appears newer.
2234
* This is to protect ourselves against database pages that were partially
2235
* or incorrectly written during a crash. We assume that the XLOG data
2236
* must be good because it has passed a CRC check, while the database
2237
* page might not be. This will force us to replay all subsequent
2238
* modifications of the page that appear in XLOG, rather than possibly
2239
* ignoring them as already applied, but that's not a huge drawback.
2242
RestoreBkpBlocks(XLogRecord *record, XLogRecPtr lsn)
2251
blk = (char *) XLogRecGetData(record) + record->xl_len;
2252
for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++)
2254
if (!(record->xl_info & XLR_SET_BKP_BLOCK(i)))
2257
memcpy((char *) &bkpb, blk, sizeof(BkpBlock));
2258
blk += sizeof(BkpBlock);
2260
reln = XLogOpenRelation(true, record->xl_rmid, bkpb.node);
2264
buffer = XLogReadBuffer(true, reln, bkpb.block);
2265
if (BufferIsValid(buffer))
2267
page = (Page) BufferGetPage(buffer);
2268
memcpy((char *) page, blk, BLCKSZ);
2269
PageSetLSN(page, lsn);
2270
PageSetTLI(page, ThisTimeLineID);
2271
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
2272
WriteBuffer(buffer);
2281
* CRC-check an XLOG record. We do not believe the contents of an XLOG
2282
* record (other than to the minimal extent of computing the amount of
2283
* data to read in) until we've checked the CRCs.
2285
* We assume all of the record has been read into memory at *record.
2288
RecordIsValid(XLogRecord *record, XLogRecPtr recptr, int emode)
2293
uint32 len = record->xl_len;
2296
/* Check CRC of rmgr data and record header */
2298
COMP_CRC64(crc, XLogRecGetData(record), len);
2299
COMP_CRC64(crc, (char *) record + sizeof(crc64),
2300
SizeOfXLogRecord - sizeof(crc64));
2303
if (!EQ_CRC64(record->xl_crc, crc))
2306
(errmsg("incorrect resource manager data checksum in record at %X/%X",
2307
recptr.xlogid, recptr.xrecoff)));
2311
/* Check CRCs of backup blocks, if any */
2312
blk = (char *) XLogRecGetData(record) + len;
2313
for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++)
2315
if (!(record->xl_info & XLR_SET_BKP_BLOCK(i)))
2319
COMP_CRC64(crc, blk + sizeof(BkpBlock), BLCKSZ);
2320
COMP_CRC64(crc, blk + sizeof(crc64),
2321
sizeof(BkpBlock) - sizeof(crc64));
2323
memcpy((char *) &cbuf, blk, sizeof(crc64)); /* don't assume
2326
if (!EQ_CRC64(cbuf, crc))
2329
(errmsg("incorrect checksum of backup block %d in record at %X/%X",
2330
i + 1, recptr.xlogid, recptr.xrecoff)));
2333
blk += sizeof(BkpBlock) + BLCKSZ;
2340
* Attempt to read an XLOG record.
2342
* If RecPtr is not NULL, try to read a record at that position. Otherwise
2343
* try to read a record just after the last one previously read.
2345
* If no valid record is available, returns NULL, or fails if emode is PANIC.
2346
* (emode must be either PANIC or LOG.)
2348
* The record is copied into readRecordBuf, so that on successful return,
2349
* the returned record pointer always points there.
2352
ReadRecord(XLogRecPtr *RecPtr, int emode)
2356
XLogRecPtr tmpRecPtr = EndRecPtr;
2357
bool randAccess = false;
2360
uint32 targetPageOff;
2361
uint32 targetRecOff;
2362
uint32 pageHeaderSize;
2365
if (readBuf == NULL)
2368
* First time through, permanently allocate readBuf. We do it
2369
* this way, rather than just making a static array, for two
2370
* reasons: (1) no need to waste the storage in most
2371
* instantiations of the backend; (2) a static char array isn't
2372
* guaranteed to have any particular alignment, whereas malloc()
2373
* will provide MAXALIGN'd storage.
2375
readBuf = (char *) malloc(BLCKSZ);
2376
Assert(readBuf != NULL);
2381
RecPtr = &tmpRecPtr;
2382
/* fast case if next record is on same page */
2383
if (nextRecord != NULL)
2385
record = nextRecord;
2388
/* align old recptr to next page */
2389
if (tmpRecPtr.xrecoff % BLCKSZ != 0)
2390
tmpRecPtr.xrecoff += (BLCKSZ - tmpRecPtr.xrecoff % BLCKSZ);
2391
if (tmpRecPtr.xrecoff >= XLogFileSize)
2393
(tmpRecPtr.xlogid)++;
2394
tmpRecPtr.xrecoff = 0;
2396
/* We will account for page header size below */
2400
if (!XRecOffIsValid(RecPtr->xrecoff))
2402
(errmsg("invalid record offset at %X/%X",
2403
RecPtr->xlogid, RecPtr->xrecoff)));
2406
* Since we are going to a random position in WAL, forget any
2407
* prior state about what timeline we were in, and allow it to be
2408
* any timeline in expectedTLIs. We also set a flag to allow
2409
* curFileTLI to go backwards (but we can't reset that variable
2410
* right here, since we might not change files at all).
2412
lastPageTLI = 0; /* see comment in ValidXLOGHeader */
2413
randAccess = true; /* allow curFileTLI to go backwards too */
2416
if (readFile >= 0 && !XLByteInSeg(*RecPtr, readId, readSeg))
2421
XLByteToSeg(*RecPtr, readId, readSeg);
2424
/* Now it's okay to reset curFileTLI if random fetch */
2428
readFile = XLogFileRead(readId, readSeg, emode);
2430
goto next_record_is_invalid;
2431
readOff = (uint32) (-1); /* force read to occur below */
2434
targetPageOff = ((RecPtr->xrecoff % XLogSegSize) / BLCKSZ) * BLCKSZ;
2435
if (readOff != targetPageOff)
2437
readOff = targetPageOff;
2438
if (lseek(readFile, (off_t) readOff, SEEK_SET) < 0)
2441
(errcode_for_file_access(),
2442
errmsg("could not seek in log file %u, segment %u to offset %u: %m",
2443
readId, readSeg, readOff)));
2444
goto next_record_is_invalid;
2446
if (read(readFile, readBuf, BLCKSZ) != BLCKSZ)
2449
(errcode_for_file_access(),
2450
errmsg("could not read from log file %u, segment %u at offset %u: %m",
2451
readId, readSeg, readOff)));
2452
goto next_record_is_invalid;
2454
if (!ValidXLOGHeader((XLogPageHeader) readBuf, emode))
2455
goto next_record_is_invalid;
2457
pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf);
2458
targetRecOff = RecPtr->xrecoff % BLCKSZ;
2459
if (targetRecOff == 0)
2462
* Can only get here in the continuing-from-prev-page case,
2463
* because XRecOffIsValid eliminated the zero-page-offset case
2464
* otherwise. Need to skip over the new page's header.
2466
tmpRecPtr.xrecoff += pageHeaderSize;
2467
targetRecOff = pageHeaderSize;
2469
else if (targetRecOff < pageHeaderSize)
2472
(errmsg("invalid record offset at %X/%X",
2473
RecPtr->xlogid, RecPtr->xrecoff)));
2474
goto next_record_is_invalid;
2476
if ((((XLogPageHeader) readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) &&
2477
targetRecOff == pageHeaderSize)
2480
(errmsg("contrecord is requested by %X/%X",
2481
RecPtr->xlogid, RecPtr->xrecoff)));
2482
goto next_record_is_invalid;
2484
record = (XLogRecord *) ((char *) readBuf + RecPtr->xrecoff % BLCKSZ);
2489
* Currently, xl_len == 0 must be bad data, but that might not be true
2490
* forever. See note in XLogInsert.
2492
if (record->xl_len == 0)
2495
(errmsg("record with zero length at %X/%X",
2496
RecPtr->xlogid, RecPtr->xrecoff)));
2497
goto next_record_is_invalid;
2499
if (record->xl_rmid > RM_MAX_ID)
2502
(errmsg("invalid resource manager ID %u at %X/%X",
2503
record->xl_rmid, RecPtr->xlogid, RecPtr->xrecoff)));
2504
goto next_record_is_invalid;
2508
* Compute total length of record including any appended backup
2511
total_len = SizeOfXLogRecord + record->xl_len;
2512
for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++)
2514
if (!(record->xl_info & XLR_SET_BKP_BLOCK(i)))
2516
total_len += sizeof(BkpBlock) + BLCKSZ;
2520
* Allocate or enlarge readRecordBuf as needed. To avoid useless
2521
* small increases, round its size to a multiple of BLCKSZ, and make
2522
* sure it's at least 4*BLCKSZ to start with. (That is enough for all
2523
* "normal" records, but very large commit or abort records might need
2526
if (total_len > readRecordBufSize)
2528
uint32 newSize = total_len;
2530
newSize += BLCKSZ - (newSize % BLCKSZ);
2531
newSize = Max(newSize, 4 * BLCKSZ);
2533
free(readRecordBuf);
2534
readRecordBuf = (char *) malloc(newSize);
2537
readRecordBufSize = 0;
2538
/* We treat this as a "bogus data" condition */
2540
(errmsg("record length %u at %X/%X too long",
2541
total_len, RecPtr->xlogid, RecPtr->xrecoff)));
2542
goto next_record_is_invalid;
2544
readRecordBufSize = newSize;
2547
buffer = readRecordBuf;
2549
len = BLCKSZ - RecPtr->xrecoff % BLCKSZ;
2550
if (total_len > len)
2552
/* Need to reassemble record */
2553
XLogContRecord *contrecord;
2554
uint32 gotlen = len;
2556
memcpy(buffer, record, len);
2557
record = (XLogRecord *) buffer;
2562
if (readOff >= XLogSegSize)
2566
NextLogSeg(readId, readSeg);
2567
readFile = XLogFileRead(readId, readSeg, emode);
2569
goto next_record_is_invalid;
2572
if (read(readFile, readBuf, BLCKSZ) != BLCKSZ)
2575
(errcode_for_file_access(),
2576
errmsg("could not read from log file %u, segment %u, offset %u: %m",
2577
readId, readSeg, readOff)));
2578
goto next_record_is_invalid;
2580
if (!ValidXLOGHeader((XLogPageHeader) readBuf, emode))
2581
goto next_record_is_invalid;
2582
if (!(((XLogPageHeader) readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD))
2585
(errmsg("there is no contrecord flag in log file %u, segment %u, offset %u",
2586
readId, readSeg, readOff)));
2587
goto next_record_is_invalid;
2589
pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf);
2590
contrecord = (XLogContRecord *) ((char *) readBuf + pageHeaderSize);
2591
if (contrecord->xl_rem_len == 0 ||
2592
total_len != (contrecord->xl_rem_len + gotlen))
2595
(errmsg("invalid contrecord length %u in log file %u, segment %u, offset %u",
2596
contrecord->xl_rem_len,
2597
readId, readSeg, readOff)));
2598
goto next_record_is_invalid;
2600
len = BLCKSZ - pageHeaderSize - SizeOfXLogContRecord;
2601
if (contrecord->xl_rem_len > len)
2603
memcpy(buffer, (char *) contrecord + SizeOfXLogContRecord, len);
2608
memcpy(buffer, (char *) contrecord + SizeOfXLogContRecord,
2609
contrecord->xl_rem_len);
2612
if (!RecordIsValid(record, *RecPtr, emode))
2613
goto next_record_is_invalid;
2614
pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf);
2615
if (BLCKSZ - SizeOfXLogRecord >= pageHeaderSize +
2616
SizeOfXLogContRecord + MAXALIGN(contrecord->xl_rem_len))
2618
nextRecord = (XLogRecord *) ((char *) contrecord +
2619
SizeOfXLogContRecord + MAXALIGN(contrecord->xl_rem_len));
2621
EndRecPtr.xlogid = readId;
2622
EndRecPtr.xrecoff = readSeg * XLogSegSize + readOff +
2623
pageHeaderSize + SizeOfXLogContRecord +
2624
MAXALIGN(contrecord->xl_rem_len);
2625
ReadRecPtr = *RecPtr;
2629
/* Record does not cross a page boundary */
2630
if (!RecordIsValid(record, *RecPtr, emode))
2631
goto next_record_is_invalid;
2632
if (BLCKSZ - SizeOfXLogRecord >= RecPtr->xrecoff % BLCKSZ +
2633
MAXALIGN(total_len))
2634
nextRecord = (XLogRecord *) ((char *) record + MAXALIGN(total_len));
2635
EndRecPtr.xlogid = RecPtr->xlogid;
2636
EndRecPtr.xrecoff = RecPtr->xrecoff + MAXALIGN(total_len);
2637
ReadRecPtr = *RecPtr;
2638
memcpy(buffer, record, total_len);
2639
return (XLogRecord *) buffer;
2641
next_record_is_invalid:;
2649
* Check whether the xlog header of a page just read in looks valid.
2651
* This is just a convenience subroutine to avoid duplicated code in
2652
* ReadRecord. It's not intended for use from anywhere else.
2655
ValidXLOGHeader(XLogPageHeader hdr, int emode)
2659
if (hdr->xlp_magic != XLOG_PAGE_MAGIC)
2662
(errmsg("invalid magic number %04X in log file %u, segment %u, offset %u",
2663
hdr->xlp_magic, readId, readSeg, readOff)));
2666
if ((hdr->xlp_info & ~XLP_ALL_FLAGS) != 0)
2669
(errmsg("invalid info bits %04X in log file %u, segment %u, offset %u",
2670
hdr->xlp_info, readId, readSeg, readOff)));
2673
if (hdr->xlp_info & XLP_LONG_HEADER)
2675
XLogLongPageHeader longhdr = (XLogLongPageHeader) hdr;
2677
if (longhdr->xlp_sysid != ControlFile->system_identifier)
2679
char fhdrident_str[32];
2680
char sysident_str[32];
2683
* Format sysids separately to keep platform-dependent format
2684
* code out of the translatable message string.
2686
snprintf(fhdrident_str, sizeof(fhdrident_str), UINT64_FORMAT,
2687
longhdr->xlp_sysid);
2688
snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT,
2689
ControlFile->system_identifier);
2691
(errmsg("WAL file is from different system"),
2692
errdetail("WAL file SYSID is %s, pg_control SYSID is %s",
2693
fhdrident_str, sysident_str)));
2696
if (longhdr->xlp_seg_size != XLogSegSize)
2699
(errmsg("WAL file is from different system"),
2700
errdetail("Incorrect XLOG_SEG_SIZE in page header.")));
2704
recaddr.xlogid = readId;
2705
recaddr.xrecoff = readSeg * XLogSegSize + readOff;
2706
if (!XLByteEQ(hdr->xlp_pageaddr, recaddr))
2709
(errmsg("unexpected pageaddr %X/%X in log file %u, segment %u, offset %u",
2710
hdr->xlp_pageaddr.xlogid, hdr->xlp_pageaddr.xrecoff,
2711
readId, readSeg, readOff)));
2716
* Check page TLI is one of the expected values.
2718
if (!list_member_int(expectedTLIs, (int) hdr->xlp_tli))
2721
(errmsg("unexpected timeline ID %u in log file %u, segment %u, offset %u",
2723
readId, readSeg, readOff)));
2728
* Since child timelines are always assigned a TLI greater than their
2729
* immediate parent's TLI, we should never see TLI go backwards across
2730
* successive pages of a consistent WAL sequence.
2732
* Of course this check should only be applied when advancing
2733
* sequentially across pages; therefore ReadRecord resets lastPageTLI
2734
* to zero when going to a random page.
2736
if (hdr->xlp_tli < lastPageTLI)
2739
(errmsg("out-of-sequence timeline ID %u (after %u) in log file %u, segment %u, offset %u",
2740
hdr->xlp_tli, lastPageTLI,
2741
readId, readSeg, readOff)));
2744
lastPageTLI = hdr->xlp_tli;
2749
* Try to read a timeline's history file.
2751
* If successful, return the list of component TLIs (the given TLI followed by
2752
* its ancestor TLIs). If we can't find the history file, assume that the
2753
* timeline has no parents, and return a list of just the specified timeline
2757
readTimeLineHistory(TimeLineID targetTLI)
2760
char path[MAXPGPATH];
2761
char histfname[MAXFNAMELEN];
2762
char fline[MAXPGPATH];
2765
if (InArchiveRecovery)
2767
TLHistoryFileName(histfname, targetTLI);
2768
RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0);
2771
TLHistoryFilePath(path, targetTLI);
2773
fd = AllocateFile(path, "r");
2776
if (errno != ENOENT)
2778
(errcode_for_file_access(),
2779
errmsg("could not open file \"%s\": %m", path)));
2780
/* Not there, so assume no parents */
2781
return list_make1_int((int) targetTLI);
2789
while (fgets(fline, MAXPGPATH, fd) != NULL)
2791
/* skip leading whitespace and check for # comment */
2796
for (ptr = fline; *ptr; ptr++)
2798
if (!isspace((unsigned char) *ptr))
2801
if (*ptr == '\0' || *ptr == '#')
2804
/* expect a numeric timeline ID as first field of line */
2805
tli = (TimeLineID) strtoul(ptr, &endptr, 0);
2808
(errmsg("syntax error in history file: %s", fline),
2809
errhint("Expected a numeric timeline ID.")));
2812
tli <= (TimeLineID) linitial_int(result))
2814
(errmsg("invalid data in history file: %s", fline),
2815
errhint("Timeline IDs must be in increasing sequence.")));
2817
/* Build list with newest item first */
2818
result = lcons_int((int) tli, result);
2820
/* we ignore the remainder of each line */
2826
targetTLI <= (TimeLineID) linitial_int(result))
2828
(errmsg("invalid data in history file \"%s\"", path),
2829
errhint("Timeline IDs must be less than child timeline's ID.")));
2831
result = lcons_int((int) targetTLI, result);
2834
(errmsg_internal("history of timeline %u is %s",
2835
targetTLI, nodeToString(result))));
2841
* Probe whether a timeline history file exists for the given timeline ID
2844
existsTimeLineHistory(TimeLineID probeTLI)
2846
char path[MAXPGPATH];
2847
char histfname[MAXFNAMELEN];
2850
if (InArchiveRecovery)
2852
TLHistoryFileName(histfname, probeTLI);
2853
RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0);
2856
TLHistoryFilePath(path, probeTLI);
2858
fd = AllocateFile(path, "r");
2866
if (errno != ENOENT)
2868
(errcode_for_file_access(),
2869
errmsg("could not open file \"%s\": %m", path)));
2875
* Find the newest existing timeline, assuming that startTLI exists.
2877
* Note: while this is somewhat heuristic, it does positively guarantee
2878
* that (result + 1) is not a known timeline, and therefore it should
2879
* be safe to assign that ID to a new timeline.
2882
findNewestTimeLine(TimeLineID startTLI)
2884
TimeLineID newestTLI;
2885
TimeLineID probeTLI;
2888
* The algorithm is just to probe for the existence of timeline
2889
* history files. XXX is it useful to allow gaps in the sequence?
2891
newestTLI = startTLI;
2893
for (probeTLI = startTLI + 1;; probeTLI++)
2895
if (existsTimeLineHistory(probeTLI))
2897
newestTLI = probeTLI; /* probeTLI exists */
2901
/* doesn't exist, assume we're done */
2910
* Create a new timeline history file.
2912
* newTLI: ID of the new timeline
2913
* parentTLI: ID of its immediate parent
2914
* endTLI et al: ID of the last used WAL file, for annotation purposes
2916
* Currently this is only used during recovery, and so there are no locking
2917
* considerations. But we should be just as tense as XLogFileInit to avoid
2918
* emplacing a bogus file.
2921
writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
2922
TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg)
2924
char path[MAXPGPATH];
2925
char tmppath[MAXPGPATH];
2926
char histfname[MAXFNAMELEN];
2927
char xlogfname[MAXFNAMELEN];
2928
char buffer[BLCKSZ];
2933
Assert(newTLI > parentTLI); /* else bad selection of newTLI */
2936
* Write into a temp file name.
2938
snprintf(tmppath, MAXPGPATH, "%s/xlogtemp.%d", XLogDir, (int)getpid());
2942
/* do not use XLOG_SYNC_BIT here --- want to fsync only at end of fill */
2943
fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL,
2947
(errcode_for_file_access(),
2948
errmsg("could not create file \"%s\": %m", tmppath)));
2951
* If a history file exists for the parent, copy it verbatim
2953
if (InArchiveRecovery)
2955
TLHistoryFileName(histfname, parentTLI);
2956
RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0);
2959
TLHistoryFilePath(path, parentTLI);
2961
srcfd = BasicOpenFile(path, O_RDONLY, 0);
2964
if (errno != ENOENT)
2966
(errcode_for_file_access(),
2967
errmsg("could not open file \"%s\": %m", path)));
2968
/* Not there, so assume parent has no parents */
2975
nbytes = (int) read(srcfd, buffer, sizeof(buffer));
2976
if (nbytes < 0 || errno != 0)
2978
(errcode_for_file_access(),
2979
errmsg("could not read file \"%s\": %m", path)));
2983
if ((int) write(fd, buffer, nbytes) != nbytes)
2985
int save_errno = errno;
2988
* If we fail to make the file, delete it to release disk
2994
* if write didn't set errno, assume problem is no disk
2997
errno = save_errno ? save_errno : ENOSPC;
3000
(errcode_for_file_access(),
3001
errmsg("could not write to file \"%s\": %m", tmppath)));
3008
* Append one line with the details of this timeline split.
3010
* If we did have a parent file, insert an extra newline just in case the
3011
* parent file failed to end with one.
3013
XLogFileName(xlogfname, endTLI, endLogId, endLogSeg);
3015
snprintf(buffer, sizeof(buffer),
3016
"%s%u\t%s\t%s transaction %u at %s\n",
3017
(srcfd < 0) ? "" : "\n",
3020
recoveryStopAfter ? "after" : "before",
3022
str_time(recoveryStopTime));
3024
nbytes = strlen(buffer);
3026
if ((int) write(fd, buffer, nbytes) != nbytes)
3028
int save_errno = errno;
3031
* If we fail to make the file, delete it to release disk space
3034
/* if write didn't set errno, assume problem is no disk space */
3035
errno = save_errno ? save_errno : ENOSPC;
3038
(errcode_for_file_access(),
3039
errmsg("could not write to file \"%s\": %m", tmppath)));
3042
if (pg_fsync(fd) != 0)
3044
(errcode_for_file_access(),
3045
errmsg("could not fsync file \"%s\": %m", tmppath)));
3049
(errcode_for_file_access(),
3050
errmsg("could not close file \"%s\": %m", tmppath)));
3054
* Now move the completed history file into place with its final name.
3056
TLHistoryFilePath(path, newTLI);
3059
* Prefer link() to rename() here just to be really sure that we don't
3060
* overwrite an existing logfile. However, there shouldn't be one, so
3061
* rename() is an acceptable substitute except for the truly paranoid.
3063
#if HAVE_WORKING_LINK
3064
if (link(tmppath, path) < 0)
3066
(errcode_for_file_access(),
3067
errmsg("could not link file \"%s\" to \"%s\": %m",
3071
if (rename(tmppath, path) < 0)
3073
(errcode_for_file_access(),
3074
errmsg("could not rename file \"%s\" to \"%s\": %m",
3078
/* The history file can be archived immediately. */
3079
TLHistoryFileName(histfname, newTLI);
3080
XLogArchiveNotify(histfname);
3084
* I/O routines for pg_control
3086
* *ControlFile is a buffer in shared memory that holds an image of the
3087
* contents of pg_control. WriteControlFile() initializes pg_control
3088
* given a preloaded buffer, ReadControlFile() loads the buffer from
3089
* the pg_control file (during postmaster or standalone-backend startup),
3090
* and UpdateControlFile() rewrites pg_control after we modify xlog state.
3092
* For simplicity, WriteControlFile() initializes the fields of pg_control
3093
* that are related to checking backend/database compatibility, and
3094
* ReadControlFile() verifies they are correct. We could split out the
3095
* I/O and compatibility-check functions, but there seems no need currently.
3101
/* Init XLOG file paths */
3102
snprintf(XLogDir, MAXPGPATH, "%s/pg_xlog", DataDir);
3103
snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir);
3107
WriteControlFile(void)
3110
char buffer[BLCKSZ]; /* need not be aligned */
3114
* Initialize version and compatibility-check fields
3116
ControlFile->pg_control_version = PG_CONTROL_VERSION;
3117
ControlFile->catalog_version_no = CATALOG_VERSION_NO;
3118
ControlFile->blcksz = BLCKSZ;
3119
ControlFile->relseg_size = RELSEG_SIZE;
3120
ControlFile->xlog_seg_size = XLOG_SEG_SIZE;
3122
ControlFile->nameDataLen = NAMEDATALEN;
3123
ControlFile->funcMaxArgs = FUNC_MAX_ARGS;
3125
#ifdef HAVE_INT64_TIMESTAMP
3126
ControlFile->enableIntTimes = TRUE;
3128
ControlFile->enableIntTimes = FALSE;
3131
ControlFile->localeBuflen = LOCALE_NAME_BUFLEN;
3132
localeptr = setlocale(LC_COLLATE, NULL);
3135
(errmsg("invalid LC_COLLATE setting")));
3136
StrNCpy(ControlFile->lc_collate, localeptr, LOCALE_NAME_BUFLEN);
3137
localeptr = setlocale(LC_CTYPE, NULL);
3140
(errmsg("invalid LC_CTYPE setting")));
3141
StrNCpy(ControlFile->lc_ctype, localeptr, LOCALE_NAME_BUFLEN);
3143
/* Contents are protected with a CRC */
3144
INIT_CRC64(ControlFile->crc);
3145
COMP_CRC64(ControlFile->crc,
3146
(char *) ControlFile + sizeof(crc64),
3147
sizeof(ControlFileData) - sizeof(crc64));
3148
FIN_CRC64(ControlFile->crc);
3151
* We write out BLCKSZ bytes into pg_control, zero-padding the excess
3152
* over sizeof(ControlFileData). This reduces the odds of
3153
* premature-EOF errors when reading pg_control. We'll still fail
3154
* when we check the contents of the file, but hopefully with a more
3155
* specific error than "couldn't read pg_control".
3157
if (sizeof(ControlFileData) > BLCKSZ)
3159
(errmsg("sizeof(ControlFileData) is larger than BLCKSZ; fix either one")));
3161
memset(buffer, 0, BLCKSZ);
3162
memcpy(buffer, ControlFile, sizeof(ControlFileData));
3164
fd = BasicOpenFile(ControlFilePath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
3168
(errcode_for_file_access(),
3169
errmsg("could not create control file \"%s\": %m",
3173
if (write(fd, buffer, BLCKSZ) != BLCKSZ)
3175
/* if write didn't set errno, assume problem is no disk space */
3179
(errcode_for_file_access(),
3180
errmsg("could not write to control file: %m")));
3183
if (pg_fsync(fd) != 0)
3185
(errcode_for_file_access(),
3186
errmsg("could not fsync control file: %m")));
3190
(errcode_for_file_access(),
3191
errmsg("could not close control file: %m")));
3195
ReadControlFile(void)
3203
fd = BasicOpenFile(ControlFilePath, O_RDWR | PG_BINARY, S_IRUSR | S_IWUSR);
3206
(errcode_for_file_access(),
3207
errmsg("could not open control file \"%s\": %m",
3210
if (read(fd, ControlFile, sizeof(ControlFileData)) != sizeof(ControlFileData))
3212
(errcode_for_file_access(),
3213
errmsg("could not read from control file: %m")));
3218
* Check for expected pg_control format version. If this is wrong,
3219
* the CRC check will likely fail because we'll be checking the wrong
3220
* number of bytes. Complaining about wrong version will probably be
3221
* more enlightening than complaining about wrong CRC.
3223
if (ControlFile->pg_control_version != PG_CONTROL_VERSION)
3225
(errmsg("database files are incompatible with server"),
3226
errdetail("The database cluster was initialized with PG_CONTROL_VERSION %d,"
3227
" but the server was compiled with PG_CONTROL_VERSION %d.",
3228
ControlFile->pg_control_version, PG_CONTROL_VERSION),
3229
errhint("It looks like you need to initdb.")));
3230
/* Now check the CRC. */
3233
(char *) ControlFile + sizeof(crc64),
3234
sizeof(ControlFileData) - sizeof(crc64));
3237
if (!EQ_CRC64(crc, ControlFile->crc))
3239
(errmsg("incorrect checksum in control file")));
3242
* Do compatibility checking immediately. We do this here for 2
3245
* (1) if the database isn't compatible with the backend executable, we
3246
* want to abort before we can possibly do any damage;
3248
* (2) this code is executed in the postmaster, so the setlocale() will
3249
* propagate to forked backends, which aren't going to read this file
3250
* for themselves. (These locale settings are considered critical
3251
* compatibility items because they can affect sort order of indexes.)
3253
if (ControlFile->catalog_version_no != CATALOG_VERSION_NO)
3255
(errmsg("database files are incompatible with server"),
3256
errdetail("The database cluster was initialized with CATALOG_VERSION_NO %d,"
3257
" but the server was compiled with CATALOG_VERSION_NO %d.",
3258
ControlFile->catalog_version_no, CATALOG_VERSION_NO),
3259
errhint("It looks like you need to initdb.")));
3260
if (ControlFile->blcksz != BLCKSZ)
3262
(errmsg("database files are incompatible with server"),
3263
errdetail("The database cluster was initialized with BLCKSZ %d,"
3264
" but the server was compiled with BLCKSZ %d.",
3265
ControlFile->blcksz, BLCKSZ),
3266
errhint("It looks like you need to recompile or initdb.")));
3267
if (ControlFile->relseg_size != RELSEG_SIZE)
3269
(errmsg("database files are incompatible with server"),
3270
errdetail("The database cluster was initialized with RELSEG_SIZE %d,"
3271
" but the server was compiled with RELSEG_SIZE %d.",
3272
ControlFile->relseg_size, RELSEG_SIZE),
3273
errhint("It looks like you need to recompile or initdb.")));
3274
if (ControlFile->xlog_seg_size != XLOG_SEG_SIZE)
3276
(errmsg("database files are incompatible with server"),
3277
errdetail("The database cluster was initialized with XLOG_SEG_SIZE %d,"
3278
" but the server was compiled with XLOG_SEG_SIZE %d.",
3279
ControlFile->xlog_seg_size, XLOG_SEG_SIZE),
3280
errhint("It looks like you need to recompile or initdb.")));
3281
if (ControlFile->nameDataLen != NAMEDATALEN)
3283
(errmsg("database files are incompatible with server"),
3284
errdetail("The database cluster was initialized with NAMEDATALEN %d,"
3285
" but the server was compiled with NAMEDATALEN %d.",
3286
ControlFile->nameDataLen, NAMEDATALEN),
3287
errhint("It looks like you need to recompile or initdb.")));
3288
if (ControlFile->funcMaxArgs != FUNC_MAX_ARGS)
3290
(errmsg("database files are incompatible with server"),
3291
errdetail("The database cluster was initialized with FUNC_MAX_ARGS %d,"
3292
" but the server was compiled with FUNC_MAX_ARGS %d.",
3293
ControlFile->funcMaxArgs, FUNC_MAX_ARGS),
3294
errhint("It looks like you need to recompile or initdb.")));
3296
#ifdef HAVE_INT64_TIMESTAMP
3297
if (ControlFile->enableIntTimes != TRUE)
3299
(errmsg("database files are incompatible with server"),
3300
errdetail("The database cluster was initialized without HAVE_INT64_TIMESTAMP"
3301
" but the server was compiled with HAVE_INT64_TIMESTAMP."),
3302
errhint("It looks like you need to recompile or initdb.")));
3304
if (ControlFile->enableIntTimes != FALSE)
3306
(errmsg("database files are incompatible with server"),
3307
errdetail("The database cluster was initialized with HAVE_INT64_TIMESTAMP"
3308
" but the server was compiled without HAVE_INT64_TIMESTAMP."),
3309
errhint("It looks like you need to recompile or initdb.")));
3312
if (ControlFile->localeBuflen != LOCALE_NAME_BUFLEN)
3314
(errmsg("database files are incompatible with server"),
3315
errdetail("The database cluster was initialized with LOCALE_NAME_BUFLEN %d,"
3316
" but the server was compiled with LOCALE_NAME_BUFLEN %d.",
3317
ControlFile->localeBuflen, LOCALE_NAME_BUFLEN),
3318
errhint("It looks like you need to recompile or initdb.")));
3319
if (setlocale(LC_COLLATE, ControlFile->lc_collate) == NULL)
3321
(errmsg("database files are incompatible with operating system"),
3322
errdetail("The database cluster was initialized with LC_COLLATE \"%s\","
3323
" which is not recognized by setlocale().",
3324
ControlFile->lc_collate),
3325
errhint("It looks like you need to initdb or install locale support.")));
3326
if (setlocale(LC_CTYPE, ControlFile->lc_ctype) == NULL)
3328
(errmsg("database files are incompatible with operating system"),
3329
errdetail("The database cluster was initialized with LC_CTYPE \"%s\","
3330
" which is not recognized by setlocale().",
3331
ControlFile->lc_ctype),
3332
errhint("It looks like you need to initdb or install locale support.")));
3334
/* Make the fixed locale settings visible as GUC variables, too */
3335
SetConfigOption("lc_collate", ControlFile->lc_collate,
3336
PGC_INTERNAL, PGC_S_OVERRIDE);
3337
SetConfigOption("lc_ctype", ControlFile->lc_ctype,
3338
PGC_INTERNAL, PGC_S_OVERRIDE);
3342
UpdateControlFile(void)
3346
INIT_CRC64(ControlFile->crc);
3347
COMP_CRC64(ControlFile->crc,
3348
(char *) ControlFile + sizeof(crc64),
3349
sizeof(ControlFileData) - sizeof(crc64));
3350
FIN_CRC64(ControlFile->crc);
3352
fd = BasicOpenFile(ControlFilePath, O_RDWR | PG_BINARY, S_IRUSR | S_IWUSR);
3355
(errcode_for_file_access(),
3356
errmsg("could not open control file \"%s\": %m",
3360
if (write(fd, ControlFile, sizeof(ControlFileData)) != sizeof(ControlFileData))
3362
/* if write didn't set errno, assume problem is no disk space */
3366
(errcode_for_file_access(),
3367
errmsg("could not write to control file: %m")));
3370
if (pg_fsync(fd) != 0)
3372
(errcode_for_file_access(),
3373
errmsg("could not fsync control file: %m")));
3377
(errcode_for_file_access(),
3378
errmsg("could not close control file: %m")));
3382
* Initialization of shared memory for XLOG
3388
if (XLOGbuffers < MinXLOGbuffers)
3389
XLOGbuffers = MinXLOGbuffers;
3391
return MAXALIGN(sizeof(XLogCtlData) + sizeof(XLogRecPtr) * XLOGbuffers)
3392
+ BLCKSZ * XLOGbuffers +
3393
MAXALIGN(sizeof(ControlFileData));
3402
/* this must agree with space requested by XLOGShmemSize() */
3403
if (XLOGbuffers < MinXLOGbuffers)
3404
XLOGbuffers = MinXLOGbuffers;
3406
XLogCtl = (XLogCtlData *)
3407
ShmemInitStruct("XLOG Ctl",
3408
MAXALIGN(sizeof(XLogCtlData) +
3409
sizeof(XLogRecPtr) * XLOGbuffers)
3410
+ BLCKSZ * XLOGbuffers,
3412
ControlFile = (ControlFileData *)
3413
ShmemInitStruct("Control File", sizeof(ControlFileData), &foundCFile);
3415
if (foundXLog || foundCFile)
3417
/* both should be present or neither */
3418
Assert(foundXLog && foundCFile);
3422
memset(XLogCtl, 0, sizeof(XLogCtlData));
3425
* Since XLogCtlData contains XLogRecPtr fields, its sizeof should be
3426
* a multiple of the alignment for same, so no extra alignment padding
3429
XLogCtl->xlblocks = (XLogRecPtr *)
3430
(((char *) XLogCtl) + sizeof(XLogCtlData));
3431
memset(XLogCtl->xlblocks, 0, sizeof(XLogRecPtr) * XLOGbuffers);
3434
* Here, on the other hand, we must MAXALIGN to ensure the page
3435
* buffers have worst-case alignment.
3438
((char *) XLogCtl) + MAXALIGN(sizeof(XLogCtlData) +
3439
sizeof(XLogRecPtr) * XLOGbuffers);
3440
memset(XLogCtl->pages, 0, BLCKSZ * XLOGbuffers);
3443
* Do basic initialization of XLogCtl shared data. (StartupXLOG will
3444
* fill in additional info.)
3446
XLogCtl->XLogCacheByte = BLCKSZ * XLOGbuffers;
3447
XLogCtl->XLogCacheBlck = XLOGbuffers - 1;
3448
XLogCtl->Insert.currpage = (XLogPageHeader) (XLogCtl->pages);
3449
SpinLockInit(&XLogCtl->info_lck);
3452
* If we are not in bootstrap mode, pg_control should already exist.
3453
* Read and validate it immediately (see comments in ReadControlFile()
3454
* for the reasons why).
3456
if (!IsBootstrapProcessingMode())
3461
* This func must be called ONCE on system install. It creates pg_control
3462
* and the initial XLOG segment.
3467
CheckPoint checkPoint;
3469
XLogPageHeader page;
3470
XLogLongPageHeader longpage;
3473
uint64 sysidentifier;
3478
* Select a hopefully-unique system identifier code for this
3479
* installation. We use the result of gettimeofday(), including the
3480
* fractional seconds field, as being about as unique as we can easily
3481
* get. (Think not to use random(), since it hasn't been seeded and
3482
* there's no portable way to seed it other than the system clock
3483
* value...) The upper half of the uint64 value is just the tv_sec
3484
* part, while the lower half is the XOR of tv_sec and tv_usec. This
3485
* is to ensure that we don't lose uniqueness unnecessarily if
3486
* "uint64" is really only 32 bits wide. A person knowing this
3487
* encoding can determine the initialization time of the installation,
3488
* which could perhaps be useful sometimes.
3490
gettimeofday(&tv, NULL);
3491
sysidentifier = ((uint64) tv.tv_sec) << 32;
3492
sysidentifier |= (uint32) (tv.tv_sec | tv.tv_usec);
3494
/* First timeline ID is always 1 */
3497
/* Use malloc() to ensure buffer is MAXALIGNED */
3498
buffer = (char *) malloc(BLCKSZ);
3499
page = (XLogPageHeader) buffer;
3500
memset(buffer, 0, BLCKSZ);
3502
/* Set up information for the initial checkpoint record */
3503
checkPoint.redo.xlogid = 0;
3504
checkPoint.redo.xrecoff = SizeOfXLogLongPHD;
3505
checkPoint.undo = checkPoint.redo;
3506
checkPoint.ThisTimeLineID = ThisTimeLineID;
3507
checkPoint.nextXid = FirstNormalTransactionId;
3508
checkPoint.nextOid = BootstrapObjectIdData;
3509
checkPoint.time = time(NULL);
3511
ShmemVariableCache->nextXid = checkPoint.nextXid;
3512
ShmemVariableCache->nextOid = checkPoint.nextOid;
3513
ShmemVariableCache->oidCount = 0;
3515
/* Set up the XLOG page header */
3516
page->xlp_magic = XLOG_PAGE_MAGIC;
3517
page->xlp_info = XLP_LONG_HEADER;
3518
page->xlp_tli = ThisTimeLineID;
3519
page->xlp_pageaddr.xlogid = 0;
3520
page->xlp_pageaddr.xrecoff = 0;
3521
longpage = (XLogLongPageHeader) page;
3522
longpage->xlp_sysid = sysidentifier;
3523
longpage->xlp_seg_size = XLogSegSize;
3525
/* Insert the initial checkpoint record */
3526
record = (XLogRecord *) ((char *) page + SizeOfXLogLongPHD);
3527
record->xl_prev.xlogid = 0;
3528
record->xl_prev.xrecoff = 0;
3529
record->xl_xid = InvalidTransactionId;
3530
record->xl_len = sizeof(checkPoint);
3531
record->xl_info = XLOG_CHECKPOINT_SHUTDOWN;
3532
record->xl_rmid = RM_XLOG_ID;
3533
memcpy(XLogRecGetData(record), &checkPoint, sizeof(checkPoint));
3536
COMP_CRC64(crc, &checkPoint, sizeof(checkPoint));
3537
COMP_CRC64(crc, (char *) record + sizeof(crc64),
3538
SizeOfXLogRecord - sizeof(crc64));
3540
record->xl_crc = crc;
3542
/* Create first XLOG segment file */
3543
use_existent = false;
3544
openLogFile = XLogFileInit(0, 0, &use_existent, false);
3546
/* Write the first page with the initial record */
3548
if (write(openLogFile, buffer, BLCKSZ) != BLCKSZ)
3550
/* if write didn't set errno, assume problem is no disk space */
3554
(errcode_for_file_access(),
3555
errmsg("could not write bootstrap transaction log file: %m")));
3558
if (pg_fsync(openLogFile) != 0)
3560
(errcode_for_file_access(),
3561
errmsg("could not fsync bootstrap transaction log file: %m")));
3563
if (close(openLogFile))
3565
(errcode_for_file_access(),
3566
errmsg("could not close bootstrap transaction log file: %m")));
3570
/* Now create pg_control */
3572
memset(ControlFile, 0, sizeof(ControlFileData));
3573
/* Initialize pg_control status fields */
3574
ControlFile->system_identifier = sysidentifier;
3575
ControlFile->state = DB_SHUTDOWNED;
3576
ControlFile->time = checkPoint.time;
3577
ControlFile->logId = 0;
3578
ControlFile->logSeg = 1;
3579
ControlFile->checkPoint = checkPoint.redo;
3580
ControlFile->checkPointCopy = checkPoint;
3581
/* some additional ControlFile fields are set in WriteControlFile() */
3585
/* Bootstrap the commit log, too */
3587
BootStrapSUBTRANS();
3591
str_time(time_t tnow)
3593
static char buf[128];
3595
strftime(buf, sizeof(buf),
3596
"%Y-%m-%d %H:%M:%S %Z",
3603
* See if there is a recovery command file (recovery.conf), and if so
3604
* read in parameters for archive recovery.
3606
* XXX longer term intention is to expand this to
3607
* cater for additional parameters and controls
3608
* possibly use a flex lexer similar to the GUC one
3611
readRecoveryCommandFile(void)
3613
char recoveryCommandFile[MAXPGPATH];
3615
char cmdline[MAXPGPATH];
3616
TimeLineID rtli = 0;
3617
bool rtliGiven = false;
3618
bool syntaxError = false;
3620
snprintf(recoveryCommandFile, MAXPGPATH, "%s/recovery.conf", DataDir);
3621
fd = AllocateFile(recoveryCommandFile, "r");
3624
if (errno == ENOENT)
3625
return; /* not there, so no archive recovery */
3627
(errcode_for_file_access(),
3628
errmsg("could not open recovery command file \"%s\": %m",
3629
recoveryCommandFile)));
3633
(errmsg("starting archive recovery")));
3638
while (fgets(cmdline, MAXPGPATH, fd) != NULL)
3640
/* skip leading whitespace and check for # comment */
3645
for (ptr = cmdline; *ptr; ptr++)
3647
if (!isspace((unsigned char) *ptr))
3650
if (*ptr == '\0' || *ptr == '#')
3653
/* identify the quoted parameter value */
3654
tok1 = strtok(ptr, "'");
3660
tok2 = strtok(NULL, "'");
3666
/* reparse to get just the parameter name */
3667
tok1 = strtok(ptr, " \t=");
3674
if (strcmp(tok1, "restore_command") == 0)
3676
recoveryRestoreCommand = pstrdup(tok2);
3678
(errmsg("restore_command = \"%s\"",
3679
recoveryRestoreCommand)));
3681
else if (strcmp(tok1, "recovery_target_timeline") == 0)
3684
if (strcmp(tok2, "latest") == 0)
3689
rtli = (TimeLineID) strtoul(tok2, NULL, 0);
3690
if (errno == EINVAL || errno == ERANGE)
3692
(errmsg("recovery_target_timeline is not a valid number: \"%s\"",
3697
(errmsg("recovery_target_timeline = %u", rtli)));
3700
(errmsg("recovery_target_timeline = latest")));
3702
else if (strcmp(tok1, "recovery_target_xid") == 0)
3705
recoveryTargetXid = (TransactionId) strtoul(tok2, NULL, 0);
3706
if (errno == EINVAL || errno == ERANGE)
3708
(errmsg("recovery_target_xid is not a valid number: \"%s\"",
3711
(errmsg("recovery_target_xid = %u",
3712
recoveryTargetXid)));
3713
recoveryTarget = true;
3714
recoveryTargetExact = true;
3716
else if (strcmp(tok1, "recovery_target_time") == 0)
3719
* if recovery_target_xid specified, then this overrides
3720
* recovery_target_time
3722
if (recoveryTargetExact)
3724
recoveryTarget = true;
3725
recoveryTargetExact = false;
3728
* Convert the time string given by the user to the time_t
3729
* format. We use type abstime's input converter because we
3730
* know abstime has the same representation as time_t.
3732
recoveryTargetTime = (time_t)
3733
DatumGetAbsoluteTime(DirectFunctionCall1(abstimein,
3734
CStringGetDatum(tok2)));
3736
(errmsg("recovery_target_time = %s",
3737
DatumGetCString(DirectFunctionCall1(abstimeout,
3738
AbsoluteTimeGetDatum((AbsoluteTime) recoveryTargetTime))))));
3740
else if (strcmp(tok1, "recovery_target_inclusive") == 0)
3743
* does nothing if a recovery_target is not also set
3745
if (strcmp(tok2, "true") == 0)
3746
recoveryTargetInclusive = true;
3749
recoveryTargetInclusive = false;
3753
(errmsg("recovery_target_inclusive = %s", tok2)));
3757
(errmsg("unrecognized recovery parameter \"%s\"",
3765
(errmsg("syntax error in recovery command file: %s",
3767
errhint("Lines should have the format parameter = 'value'.")));
3769
/* Check that required parameters were supplied */
3770
if (recoveryRestoreCommand == NULL)
3772
(errmsg("recovery command file \"%s\" did not specify restore_command",
3773
recoveryCommandFile)));
3775
/* Enable fetching from archive recovery area */
3776
InArchiveRecovery = true;
3779
* If user specified recovery_target_timeline, validate it or compute
3780
* the "latest" value. We can't do this until after we've gotten the
3781
* restore command and set InArchiveRecovery, because we need to fetch
3782
* timeline history files from the archive.
3788
/* Timeline 1 does not have a history file, all else should */
3789
if (rtli != 1 && !existsTimeLineHistory(rtli))
3791
(errmsg("recovery_target_timeline %u does not exist",
3793
recoveryTargetTLI = rtli;
3797
/* We start the "latest" search from pg_control's timeline */
3798
recoveryTargetTLI = findNewestTimeLine(recoveryTargetTLI);
3804
* Exit archive-recovery state
3807
exitArchiveRecovery(TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg)
3809
char recoveryPath[MAXPGPATH];
3810
char xlogpath[MAXPGPATH];
3811
char recoveryCommandFile[MAXPGPATH];
3812
char recoveryCommandDone[MAXPGPATH];
3815
* We are no longer in archive recovery state.
3817
InArchiveRecovery = false;
3820
* We should have the ending log segment currently open. Verify, and
3821
* then close it (to avoid problems on Windows with trying to rename
3822
* or delete an open file).
3824
Assert(readFile >= 0);
3825
Assert(readId == endLogId);
3826
Assert(readSeg == endLogSeg);
3832
* If the segment was fetched from archival storage, we want to
3833
* replace the existing xlog segment (if any) with the archival
3834
* version. This is because whatever is in XLogDir is very possibly
3835
* older than what we have from the archives, since it could have come
3836
* from restoring a PGDATA backup. In any case, the archival version
3837
* certainly is more descriptive of what our current database state
3838
* is, because that is what we replayed from.
3840
* Note that if we are establishing a new timeline, ThisTimeLineID is
3841
* already set to the new value, and so we will create a new file
3842
* instead of overwriting any existing file.
3844
snprintf(recoveryPath, MAXPGPATH, "%s/RECOVERYXLOG", XLogDir);
3845
XLogFilePath(xlogpath, ThisTimeLineID, endLogId, endLogSeg);
3847
if (restoredFromArchive)
3850
(errmsg_internal("moving last restored xlog to \"%s\"",
3852
unlink(xlogpath); /* might or might not exist */
3853
if (rename(recoveryPath, xlogpath) != 0)
3855
(errcode_for_file_access(),
3856
errmsg("could not rename file \"%s\" to \"%s\": %m",
3857
recoveryPath, xlogpath)));
3858
/* XXX might we need to fix permissions on the file? */
3863
* If the latest segment is not archival, but there's still a
3864
* RECOVERYXLOG laying about, get rid of it.
3866
unlink(recoveryPath); /* ignore any error */
3869
* If we are establishing a new timeline, we have to copy data
3870
* from the last WAL segment of the old timeline to create a
3871
* starting WAL segment for the new timeline.
3873
if (endTLI != ThisTimeLineID)
3874
XLogFileCopy(endLogId, endLogSeg,
3875
endTLI, endLogId, endLogSeg);
3879
* Let's just make real sure there are not .ready or .done flags
3880
* posted for the new segment.
3882
XLogFileName(xlogpath, ThisTimeLineID, endLogId, endLogSeg);
3883
XLogArchiveCleanup(xlogpath);
3885
/* Get rid of any remaining recovered timeline-history file, too */
3886
snprintf(recoveryPath, MAXPGPATH, "%s/RECOVERYHISTORY", XLogDir);
3887
unlink(recoveryPath); /* ignore any error */
3890
* Rename the config file out of the way, so that we don't
3891
* accidentally re-enter archive recovery mode in a subsequent crash.
3893
snprintf(recoveryCommandFile, MAXPGPATH, "%s/recovery.conf", DataDir);
3894
snprintf(recoveryCommandDone, MAXPGPATH, "%s/recovery.done", DataDir);
3895
unlink(recoveryCommandDone);
3896
if (rename(recoveryCommandFile, recoveryCommandDone) != 0)
3898
(errcode_for_file_access(),
3899
errmsg("could not rename file \"%s\" to \"%s\": %m",
3900
recoveryCommandFile, recoveryCommandDone)));
3903
(errmsg("archive recovery complete")));
3907
* For point-in-time recovery, this function decides whether we want to
3908
* stop applying the XLOG at or after the current record.
3910
* Returns TRUE if we are stopping, FALSE otherwise. On TRUE return,
3911
* *includeThis is set TRUE if we should apply this record before stopping.
3912
* Also, some information is saved in recoveryStopXid et al for use in
3913
* annotating the new timeline's history file.
3916
recoveryStopsHere(XLogRecord *record, bool *includeThis)
3922
/* Do we have a PITR target at all? */
3923
if (!recoveryTarget)
3926
/* We only consider stopping at COMMIT or ABORT records */
3927
if (record->xl_rmid != RM_XACT_ID)
3929
record_info = record->xl_info & ~XLR_INFO_MASK;
3930
if (record_info == XLOG_XACT_COMMIT)
3932
xl_xact_commit *recordXactCommitData;
3934
recordXactCommitData = (xl_xact_commit *) XLogRecGetData(record);
3935
recordXtime = recordXactCommitData->xtime;
3937
else if (record_info == XLOG_XACT_ABORT)
3939
xl_xact_abort *recordXactAbortData;
3941
recordXactAbortData = (xl_xact_abort *) XLogRecGetData(record);
3942
recordXtime = recordXactAbortData->xtime;
3947
if (recoveryTargetExact)
3950
* there can be only one transaction end record with this exact
3953
* when testing for an xid, we MUST test for equality only, since
3954
* transactions are numbered in the order they start, not the
3955
* order they complete. A higher numbered xid will complete before
3956
* you about 50% of the time...
3958
stopsHere = (record->xl_xid == recoveryTargetXid);
3960
*includeThis = recoveryTargetInclusive;
3965
* there can be many transactions that share the same commit time,
3966
* so we stop after the last one, if we are inclusive, or stop at
3967
* the first one if we are exclusive
3969
if (recoveryTargetInclusive)
3970
stopsHere = (recordXtime > recoveryTargetTime);
3972
stopsHere = (recordXtime >= recoveryTargetTime);
3974
*includeThis = false;
3979
recoveryStopXid = record->xl_xid;
3980
recoveryStopTime = recordXtime;
3981
recoveryStopAfter = *includeThis;
3983
if (record_info == XLOG_XACT_COMMIT)
3985
if (recoveryStopAfter)
3987
(errmsg("recovery stopping after commit of transaction %u, time %s",
3988
recoveryStopXid, str_time(recoveryStopTime))));
3991
(errmsg("recovery stopping before commit of transaction %u, time %s",
3992
recoveryStopXid, str_time(recoveryStopTime))));
3996
if (recoveryStopAfter)
3998
(errmsg("recovery stopping after abort of transaction %u, time %s",
3999
recoveryStopXid, str_time(recoveryStopTime))));
4002
(errmsg("recovery stopping before abort of transaction %u, time %s",
4003
recoveryStopXid, str_time(recoveryStopTime))));
4011
* This must be called ONCE during postmaster or standalone-backend startup
4016
XLogCtlInsert *Insert;
4017
CheckPoint checkPoint;
4019
bool needNewTimeLine = false;
4032
* Read control file and check XLOG status looks valid.
4034
* Note: in most control paths, *ControlFile is already valid and we need
4035
* not do ReadControlFile() here, but might as well do it to be sure.
4039
if (ControlFile->logSeg == 0 ||
4040
ControlFile->state < DB_SHUTDOWNED ||
4041
ControlFile->state > DB_IN_PRODUCTION ||
4042
!XRecOffIsValid(ControlFile->checkPoint.xrecoff))
4044
(errmsg("control file contains invalid data")));
4046
if (ControlFile->state == DB_SHUTDOWNED)
4048
(errmsg("database system was shut down at %s",
4049
str_time(ControlFile->time))));
4050
else if (ControlFile->state == DB_SHUTDOWNING)
4052
(errmsg("database system shutdown was interrupted at %s",
4053
str_time(ControlFile->time))));
4054
else if (ControlFile->state == DB_IN_RECOVERY)
4056
(errmsg("database system was interrupted while in recovery at %s",
4057
str_time(ControlFile->time)),
4058
errhint("This probably means that some data is corrupted and"
4059
" you will have to use the last backup for recovery.")));
4060
else if (ControlFile->state == DB_IN_PRODUCTION)
4062
(errmsg("database system was interrupted at %s",
4063
str_time(ControlFile->time))));
4065
/* This is just to allow attaching to startup process with a debugger */
4066
#ifdef XLOG_REPLAY_DELAY
4067
if (ControlFile->state != DB_SHUTDOWNED)
4068
pg_usleep(60000000L);
4072
* Initialize on the assumption we want to recover to the same
4073
* timeline that's active according to pg_control.
4075
recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
4078
* Check for recovery control file, and if so set up state for offline
4081
readRecoveryCommandFile();
4083
/* Now we can determine the list of expected TLIs */
4084
expectedTLIs = readTimeLineHistory(recoveryTargetTLI);
4087
* If pg_control's timeline is not in expectedTLIs, then we cannot
4088
* proceed: the backup is not part of the history of the requested
4091
if (!list_member_int(expectedTLIs,
4092
(int) ControlFile->checkPointCopy.ThisTimeLineID))
4094
(errmsg("requested timeline %u is not a child of database system timeline %u",
4096
ControlFile->checkPointCopy.ThisTimeLineID)));
4098
if (read_backup_label(&checkPointLoc))
4101
* When a backup_label file is present, we want to roll forward
4102
* from the checkpoint it identifies, rather than using
4105
record = ReadCheckpointRecord(checkPointLoc, 0);
4109
(errmsg("checkpoint record is at %X/%X",
4110
checkPointLoc.xlogid, checkPointLoc.xrecoff)));
4111
InRecovery = true; /* force recovery even if SHUTDOWNED */
4116
(errmsg("could not locate required checkpoint record"),
4117
errhint("If you are not restoring from a backup, try removing the file \"%s/backup_label\".", DataDir)));
4123
* Get the last valid checkpoint record. If the latest one
4124
* according to pg_control is broken, try the next-to-last one.
4126
checkPointLoc = ControlFile->checkPoint;
4127
record = ReadCheckpointRecord(checkPointLoc, 1);
4131
(errmsg("checkpoint record is at %X/%X",
4132
checkPointLoc.xlogid, checkPointLoc.xrecoff)));
4136
checkPointLoc = ControlFile->prevCheckPoint;
4137
record = ReadCheckpointRecord(checkPointLoc, 2);
4141
(errmsg("using previous checkpoint record at %X/%X",
4142
checkPointLoc.xlogid, checkPointLoc.xrecoff)));
4143
InRecovery = true; /* force recovery even if
4148
(errmsg("could not locate a valid checkpoint record")));
4152
LastRec = RecPtr = checkPointLoc;
4153
memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint));
4154
wasShutdown = (record->xl_info == XLOG_CHECKPOINT_SHUTDOWN);
4157
(errmsg("redo record is at %X/%X; undo record is at %X/%X; shutdown %s",
4158
checkPoint.redo.xlogid, checkPoint.redo.xrecoff,
4159
checkPoint.undo.xlogid, checkPoint.undo.xrecoff,
4160
wasShutdown ? "TRUE" : "FALSE")));
4162
(errmsg("next transaction ID: %u; next OID: %u",
4163
checkPoint.nextXid, checkPoint.nextOid)));
4164
if (!TransactionIdIsNormal(checkPoint.nextXid))
4166
(errmsg("invalid next transaction ID")));
4168
ShmemVariableCache->nextXid = checkPoint.nextXid;
4169
ShmemVariableCache->nextOid = checkPoint.nextOid;
4170
ShmemVariableCache->oidCount = 0;
4173
* We must replay WAL entries using the same TimeLineID they were
4174
* created under, so temporarily adopt the TLI indicated by the
4175
* checkpoint (see also xlog_redo()).
4177
ThisTimeLineID = checkPoint.ThisTimeLineID;
4179
RedoRecPtr = XLogCtl->Insert.RedoRecPtr = checkPoint.redo;
4181
if (XLByteLT(RecPtr, checkPoint.redo))
4183
(errmsg("invalid redo in checkpoint record")));
4184
if (checkPoint.undo.xrecoff == 0)
4185
checkPoint.undo = RecPtr;
4188
* Check whether we need to force recovery from WAL. If it appears to
4189
* have been a clean shutdown and we did not have a recovery.conf
4190
* file, then assume no recovery needed.
4192
if (XLByteLT(checkPoint.undo, RecPtr) ||
4193
XLByteLT(checkPoint.redo, RecPtr))
4197
(errmsg("invalid redo/undo record in shutdown checkpoint")));
4200
else if (ControlFile->state != DB_SHUTDOWNED)
4202
else if (InArchiveRecovery)
4204
/* force recovery due to presence of recovery.conf */
4213
if (InArchiveRecovery)
4215
(errmsg("automatic recovery in progress")));
4218
(errmsg("database system was not properly shut down; "
4219
"automatic recovery in progress")));
4220
ControlFile->state = DB_IN_RECOVERY;
4221
ControlFile->time = time(NULL);
4222
UpdateControlFile();
4224
/* Start up the recovery environment */
4225
XLogInitRelationCache();
4227
for (rmid = 0; rmid <= RM_MAX_ID; rmid++)
4229
if (RmgrTable[rmid].rm_startup != NULL)
4230
RmgrTable[rmid].rm_startup();
4234
* Find the first record that logically follows the checkpoint ---
4235
* it might physically precede it, though.
4237
if (XLByteLT(checkPoint.redo, RecPtr))
4239
/* back up to find the record */
4240
record = ReadRecord(&(checkPoint.redo), PANIC);
4244
/* just have to read next record after CheckPoint */
4245
record = ReadRecord(NULL, LOG);
4250
bool recoveryContinue = true;
4251
bool recoveryApply = true;
4255
(errmsg("redo starts at %X/%X",
4256
ReadRecPtr.xlogid, ReadRecPtr.xrecoff)));
4259
* main redo apply loop
4268
sprintf(buf, "REDO @ %X/%X; LSN %X/%X: ",
4269
ReadRecPtr.xlogid, ReadRecPtr.xrecoff,
4270
EndRecPtr.xlogid, EndRecPtr.xrecoff);
4271
xlog_outrec(buf, record);
4273
RmgrTable[record->xl_rmid].rm_desc(buf,
4274
record->xl_info, XLogRecGetData(record));
4275
elog(LOG, "%s", buf);
4280
* Have we reached our recovery target?
4282
if (recoveryStopsHere(record, &recoveryApply))
4284
needNewTimeLine = true; /* see below */
4285
recoveryContinue = false;
4290
/* nextXid must be beyond record's xid */
4291
if (TransactionIdFollowsOrEquals(record->xl_xid,
4292
ShmemVariableCache->nextXid))
4294
ShmemVariableCache->nextXid = record->xl_xid;
4295
TransactionIdAdvance(ShmemVariableCache->nextXid);
4298
if (record->xl_info & XLR_BKP_BLOCK_MASK)
4299
RestoreBkpBlocks(record, EndRecPtr);
4301
RmgrTable[record->xl_rmid].rm_redo(EndRecPtr, record);
4303
LastRec = ReadRecPtr;
4305
record = ReadRecord(NULL, LOG);
4306
} while (record != NULL && recoveryContinue);
4309
* end of main redo apply loop
4313
(errmsg("redo done at %X/%X",
4314
ReadRecPtr.xlogid, ReadRecPtr.xrecoff)));
4319
/* there are no WAL records following the checkpoint */
4321
(errmsg("redo is not required")));
4326
* Re-fetch the last valid or last applied record, so we can identify
4327
* the exact endpoint of what we consider the valid portion of WAL.
4329
record = ReadRecord(&LastRec, PANIC);
4330
EndOfLog = EndRecPtr;
4331
XLByteToPrevSeg(EndOfLog, endLogId, endLogSeg);
4334
* Complain if we did not roll forward far enough to render the backup
4337
if (XLByteLT(EndOfLog, recoveryMinXlogOffset))
4339
if (needNewTimeLine) /* stopped because of stop request */
4341
(errmsg("requested recovery stop point is before end time of backup dump")));
4343
/* ran off end of WAL */
4345
(errmsg("WAL ends before end time of backup dump")));
4349
* Consider whether we need to assign a new timeline ID.
4351
* If we stopped short of the end of WAL during recovery, then we are
4352
* generating a new timeline and must assign it a unique new ID.
4353
* Otherwise, we can just extend the timeline we were in when we ran
4356
if (needNewTimeLine)
4358
ThisTimeLineID = findNewestTimeLine(recoveryTargetTLI) + 1;
4360
(errmsg("selected new timeline ID: %u", ThisTimeLineID)));
4361
writeTimeLineHistory(ThisTimeLineID, recoveryTargetTLI,
4362
curFileTLI, endLogId, endLogSeg);
4365
/* Save the selected TimeLineID in shared memory, too */
4366
XLogCtl->ThisTimeLineID = ThisTimeLineID;
4369
* We are now done reading the old WAL. Turn off archive fetching if
4370
* it was active, and make a writable copy of the last WAL segment.
4371
* (Note that we also have a copy of the last block of the old WAL in
4372
* readBuf; we will use that below.)
4374
if (InArchiveRecovery)
4375
exitArchiveRecovery(curFileTLI, endLogId, endLogSeg);
4378
* Prepare to write WAL starting at EndOfLog position, and init xlog
4379
* buffer cache using the block containing the last record from the
4380
* previous incarnation.
4382
openLogId = endLogId;
4383
openLogSeg = endLogSeg;
4384
openLogFile = XLogFileOpen(openLogId, openLogSeg);
4386
ControlFile->logId = openLogId;
4387
ControlFile->logSeg = openLogSeg + 1;
4388
Insert = &XLogCtl->Insert;
4389
Insert->PrevRecord = LastRec;
4390
XLogCtl->xlblocks[0].xlogid = openLogId;
4391
XLogCtl->xlblocks[0].xrecoff =
4392
((EndOfLog.xrecoff - 1) / BLCKSZ + 1) * BLCKSZ;
4395
* Tricky point here: readBuf contains the *last* block that the
4396
* LastRec record spans, not the one it starts in. The last block is
4397
* indeed the one we want to use.
4399
Assert(readOff == (XLogCtl->xlblocks[0].xrecoff - BLCKSZ) % XLogSegSize);
4400
memcpy((char *) Insert->currpage, readBuf, BLCKSZ);
4401
Insert->currpos = (char *) Insert->currpage +
4402
(EndOfLog.xrecoff + BLCKSZ - XLogCtl->xlblocks[0].xrecoff);
4404
LogwrtResult.Write = LogwrtResult.Flush = EndOfLog;
4406
XLogCtl->Write.LogwrtResult = LogwrtResult;
4407
Insert->LogwrtResult = LogwrtResult;
4408
XLogCtl->LogwrtResult = LogwrtResult;
4410
XLogCtl->LogwrtRqst.Write = EndOfLog;
4411
XLogCtl->LogwrtRqst.Flush = EndOfLog;
4413
freespace = INSERT_FREESPACE(Insert);
4416
/* Make sure rest of page is zero */
4417
MemSet(Insert->currpos, 0, freespace);
4418
XLogCtl->Write.curridx = 0;
4423
* Whenever Write.LogwrtResult points to exactly the end of a
4424
* page, Write.curridx must point to the *next* page (see
4427
* Note: it might seem we should do AdvanceXLInsertBuffer() here, but
4428
* this is sufficient. The first actual attempt to insert a log
4429
* record will advance the insert state.
4431
XLogCtl->Write.curridx = NextBufIdx(0);
4438
RecPtr = ReadRecPtr;
4439
if (XLByteLT(checkPoint.undo, RecPtr))
4442
(errmsg("undo starts at %X/%X",
4443
RecPtr.xlogid, RecPtr.xrecoff)));
4446
record = ReadRecord(&RecPtr, PANIC);
4447
if (TransactionIdIsValid(record->xl_xid) &&
4448
!TransactionIdDidCommit(record->xl_xid))
4449
RmgrTable[record->xl_rmid].rm_undo(EndRecPtr, record);
4450
RecPtr = record->xl_prev;
4451
} while (XLByteLE(checkPoint.undo, RecPtr));
4453
(errmsg("undo done at %X/%X",
4454
ReadRecPtr.xlogid, ReadRecPtr.xrecoff)));
4458
(errmsg("undo is not required")));
4467
* Allow resource managers to do any required cleanup.
4469
for (rmid = 0; rmid <= RM_MAX_ID; rmid++)
4471
if (RmgrTable[rmid].rm_cleanup != NULL)
4472
RmgrTable[rmid].rm_cleanup();
4476
* Perform a new checkpoint to update our recovery activity to
4479
* Note that we write a shutdown checkpoint rather than an on-line
4480
* one. This is not particularly critical, but since we may be
4481
* assigning a new TLI, using a shutdown checkpoint allows us to
4482
* have the rule that TLI only changes in shutdown checkpoints,
4483
* which allows some extra error checking in xlog_redo.
4485
* In case we had to use the secondary checkpoint, make sure that it
4486
* will still be shown as the secondary checkpoint after this
4487
* CreateCheckPoint operation; we don't want the broken primary
4488
* checkpoint to become prevCheckPoint...
4490
if (XLByteEQ(checkPointLoc, ControlFile->prevCheckPoint))
4491
ControlFile->checkPoint = checkPointLoc;
4493
CreateCheckPoint(true, true);
4496
* Close down recovery environment
4498
XLogCloseRelationCache();
4501
* Now that we've checkpointed the recovery, it's safe to flush
4502
* old backup_label, if present.
4504
remove_backup_label();
4508
* Preallocate additional log files, if wanted.
4510
(void) PreallocXlogFiles(EndOfLog);
4513
* Okay, we're officially UP.
4517
ControlFile->state = DB_IN_PRODUCTION;
4518
ControlFile->time = time(NULL);
4519
UpdateControlFile();
4521
/* Start up the commit log, too */
4526
(errmsg("database system is ready")));
4529
/* Shut down readFile facility, free space */
4542
free(readRecordBuf);
4543
readRecordBuf = NULL;
4544
readRecordBufSize = 0;
4549
* Subroutine to try to fetch and validate a prior checkpoint record.
4551
* whichChkpt identifies the checkpoint (merely for reporting purposes).
4552
* 1 for "primary", 2 for "secondary", 0 for "other" (backup_label)
4555
ReadCheckpointRecord(XLogRecPtr RecPtr, int whichChkpt)
4559
if (!XRecOffIsValid(RecPtr.xrecoff))
4565
(errmsg("invalid primary checkpoint link in control file")));
4569
(errmsg("invalid secondary checkpoint link in control file")));
4573
(errmsg("invalid checkpoint link in backup_label file")));
4579
record = ReadRecord(&RecPtr, LOG);
4587
(errmsg("invalid primary checkpoint record")));
4591
(errmsg("invalid secondary checkpoint record")));
4595
(errmsg("invalid checkpoint record")));
4600
if (record->xl_rmid != RM_XLOG_ID)
4606
(errmsg("invalid resource manager ID in primary checkpoint record")));
4610
(errmsg("invalid resource manager ID in secondary checkpoint record")));
4614
(errmsg("invalid resource manager ID in checkpoint record")));
4619
if (record->xl_info != XLOG_CHECKPOINT_SHUTDOWN &&
4620
record->xl_info != XLOG_CHECKPOINT_ONLINE)
4626
(errmsg("invalid xl_info in primary checkpoint record")));
4630
(errmsg("invalid xl_info in secondary checkpoint record")));
4634
(errmsg("invalid xl_info in checkpoint record")));
4639
if (record->xl_len != sizeof(CheckPoint))
4645
(errmsg("invalid length of primary checkpoint record")));
4649
(errmsg("invalid length of secondary checkpoint record")));
4653
(errmsg("invalid length of checkpoint record")));
4662
* This must be called during startup of a backend process, except that
4663
* it need not be called in a standalone backend (which does StartupXLOG
4664
* instead). We need to initialize the local copies of ThisTimeLineID and
4667
* Note: before Postgres 8.0, we went to some effort to keep the postmaster
4668
* process's copies of ThisTimeLineID and RedoRecPtr valid too. This was
4669
* unnecessary however, since the postmaster itself never touches XLOG anyway.
4672
InitXLOGAccess(void)
4674
/* ThisTimeLineID doesn't change so we need no lock to copy it */
4675
ThisTimeLineID = XLogCtl->ThisTimeLineID;
4676
/* Use GetRedoRecPtr to copy the RedoRecPtr safely */
4677
(void) GetRedoRecPtr();
4681
* Once spawned, a backend may update its local RedoRecPtr from
4682
* XLogCtl->Insert.RedoRecPtr; it must hold the insert lock or info_lck
4683
* to do so. This is done in XLogInsert() or GetRedoRecPtr().
4688
/* use volatile pointer to prevent code rearrangement */
4689
volatile XLogCtlData *xlogctl = XLogCtl;
4691
SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
4692
Assert(XLByteLE(RedoRecPtr, xlogctl->Insert.RedoRecPtr));
4693
RedoRecPtr = xlogctl->Insert.RedoRecPtr;
4694
SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
4700
* This must be called ONCE during postmaster or standalone-backend shutdown
4703
ShutdownXLOG(int code, Datum arg)
4706
(errmsg("shutting down")));
4709
CreateCheckPoint(true, true);
4715
(errmsg("database system is shut down")));
4719
* Perform a checkpoint --- either during shutdown, or on-the-fly
4721
* If force is true, we force a checkpoint regardless of whether any XLOG
4722
* activity has occurred since the last one.
4725
CreateCheckPoint(bool shutdown, bool force)
4727
CheckPoint checkPoint;
4729
XLogCtlInsert *Insert = &XLogCtl->Insert;
4735
int nsegsremoved = 0;
4736
int nsegsrecycled = 0;
4739
* Acquire CheckpointLock to ensure only one checkpoint happens at a
4740
* time. (This is just pro forma, since in the present system
4741
* structure there is only one process that is allowed to issue
4742
* checkpoints at any given time.)
4744
LWLockAcquire(CheckpointLock, LW_EXCLUSIVE);
4747
* Use a critical section to force system panic if we have trouble.
4749
START_CRIT_SECTION();
4753
ControlFile->state = DB_SHUTDOWNING;
4754
ControlFile->time = time(NULL);
4755
UpdateControlFile();
4758
MemSet(&checkPoint, 0, sizeof(checkPoint));
4759
checkPoint.ThisTimeLineID = ThisTimeLineID;
4760
checkPoint.time = time(NULL);
4763
* We must hold CheckpointStartLock while determining the checkpoint
4764
* REDO pointer. This ensures that any concurrent transaction commits
4765
* will be either not yet logged, or logged and recorded in pg_clog.
4766
* See notes in RecordTransactionCommit().
4768
LWLockAcquire(CheckpointStartLock, LW_EXCLUSIVE);
4770
/* And we need WALInsertLock too */
4771
LWLockAcquire(WALInsertLock, LW_EXCLUSIVE);
4774
* If this isn't a shutdown or forced checkpoint, and we have not
4775
* inserted any XLOG records since the start of the last checkpoint,
4776
* skip the checkpoint. The idea here is to avoid inserting duplicate
4777
* checkpoints when the system is idle. That wastes log space, and
4778
* more importantly it exposes us to possible loss of both current and
4779
* previous checkpoint records if the machine crashes just as we're
4780
* writing the update. (Perhaps it'd make even more sense to
4781
* checkpoint only when the previous checkpoint record is in a
4782
* different xlog page?)
4784
* We have to make two tests to determine that nothing has happened since
4785
* the start of the last checkpoint: current insertion point must
4786
* match the end of the last checkpoint record, and its redo pointer
4787
* must point to itself.
4789
if (!shutdown && !force)
4791
XLogRecPtr curInsert;
4793
INSERT_RECPTR(curInsert, Insert, Insert->curridx);
4794
if (curInsert.xlogid == ControlFile->checkPoint.xlogid &&
4795
curInsert.xrecoff == ControlFile->checkPoint.xrecoff +
4796
MAXALIGN(SizeOfXLogRecord + sizeof(CheckPoint)) &&
4797
ControlFile->checkPoint.xlogid ==
4798
ControlFile->checkPointCopy.redo.xlogid &&
4799
ControlFile->checkPoint.xrecoff ==
4800
ControlFile->checkPointCopy.redo.xrecoff)
4802
LWLockRelease(WALInsertLock);
4803
LWLockRelease(CheckpointStartLock);
4804
LWLockRelease(CheckpointLock);
4811
* Compute new REDO record ptr = location of next XLOG record.
4813
* NB: this is NOT necessarily where the checkpoint record itself will
4814
* be, since other backends may insert more XLOG records while we're
4815
* off doing the buffer flush work. Those XLOG records are logically
4816
* after the checkpoint, even though physically before it. Got that?
4818
freespace = INSERT_FREESPACE(Insert);
4819
if (freespace < SizeOfXLogRecord)
4821
(void) AdvanceXLInsertBuffer();
4822
/* OK to ignore update return flag, since we will do flush anyway */
4823
freespace = INSERT_FREESPACE(Insert);
4825
INSERT_RECPTR(checkPoint.redo, Insert, Insert->curridx);
4828
* Here we update the shared RedoRecPtr for future XLogInsert calls;
4829
* this must be done while holding the insert lock AND the info_lck.
4831
* Note: if we fail to complete the checkpoint, RedoRecPtr will be left
4832
* pointing past where it really needs to point. This is okay; the
4833
* only consequence is that XLogInsert might back up whole buffers
4834
* that it didn't really need to. We can't postpone advancing
4835
* RedoRecPtr because XLogInserts that happen while we are dumping
4836
* buffers must assume that their buffer changes are not included in
4840
/* use volatile pointer to prevent code rearrangement */
4841
volatile XLogCtlData *xlogctl = XLogCtl;
4843
SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
4844
RedoRecPtr = xlogctl->Insert.RedoRecPtr = checkPoint.redo;
4845
SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
4849
* Get UNDO record ptr - this is oldest of PGPROC->logRec values. We
4850
* do this while holding insert lock to ensure that we won't miss any
4851
* about-to-commit transactions (UNDO must include all xacts that have
4852
* commits after REDO point).
4854
* XXX temporarily ifdef'd out to avoid three-way deadlock condition:
4855
* GetUndoRecPtr needs to grab SInvalLock to ensure that it is looking
4856
* at a stable set of proc records, but grabbing SInvalLock while
4857
* holding WALInsertLock is no good. GetNewTransactionId may cause a
4858
* WAL record to be written while holding XidGenLock, and
4859
* GetSnapshotData needs to get XidGenLock while holding SInvalLock,
4860
* so there's a risk of deadlock. Need to find a better solution. See
4861
* pgsql-hackers discussion of 17-Dec-01.
4863
* XXX actually, the whole UNDO code is dead code and unlikely to ever be
4864
* revived, so the lack of a good solution here is not troubling.
4867
checkPoint.undo = GetUndoRecPtr();
4869
if (shutdown && checkPoint.undo.xrecoff != 0)
4870
elog(PANIC, "active transaction while database system is shutting down");
4874
* Now we can release insert lock and checkpoint start lock, allowing
4875
* other xacts to proceed even while we are flushing disk buffers.
4877
LWLockRelease(WALInsertLock);
4879
LWLockRelease(CheckpointStartLock);
4882
* Get the other info we need for the checkpoint record.
4884
LWLockAcquire(XidGenLock, LW_SHARED);
4885
checkPoint.nextXid = ShmemVariableCache->nextXid;
4886
LWLockRelease(XidGenLock);
4888
LWLockAcquire(OidGenLock, LW_SHARED);
4889
checkPoint.nextOid = ShmemVariableCache->nextOid;
4891
checkPoint.nextOid += ShmemVariableCache->oidCount;
4892
LWLockRelease(OidGenLock);
4895
* Having constructed the checkpoint record, ensure all shmem disk
4896
* buffers and commit-log buffers are flushed to disk.
4898
* This I/O could fail for various reasons. If so, we will fail to
4899
* complete the checkpoint, but there is no reason to force a system
4900
* panic. Accordingly, exit critical section while doing it.
4906
(errmsg("checkpoint starting")));
4909
CheckPointSUBTRANS();
4912
START_CRIT_SECTION();
4915
* Now insert the checkpoint record into XLOG.
4917
rdata.buffer = InvalidBuffer;
4918
rdata.data = (char *) (&checkPoint);
4919
rdata.len = sizeof(checkPoint);
4922
recptr = XLogInsert(RM_XLOG_ID,
4923
shutdown ? XLOG_CHECKPOINT_SHUTDOWN :
4924
XLOG_CHECKPOINT_ONLINE,
4930
* We now have ProcLastRecPtr = start of actual checkpoint record,
4931
* recptr = end of actual checkpoint record.
4933
if (shutdown && !XLByteEQ(checkPoint.redo, ProcLastRecPtr))
4935
(errmsg("concurrent transaction log activity while database system is shutting down")));
4938
* Select point at which we can truncate the log, which we base on the
4939
* prior checkpoint's earliest info.
4941
* With UNDO support: oldest item is redo or undo, whichever is older;
4942
* but watch out for case that undo = 0.
4944
* Without UNDO support: just use the redo pointer. This allows xlog
4945
* space to be freed much faster when there are long-running
4949
if (ControlFile->checkPointCopy.undo.xrecoff != 0 &&
4950
XLByteLT(ControlFile->checkPointCopy.undo,
4951
ControlFile->checkPointCopy.redo))
4952
XLByteToSeg(ControlFile->checkPointCopy.undo, _logId, _logSeg);
4955
XLByteToSeg(ControlFile->checkPointCopy.redo, _logId, _logSeg);
4958
* Update the control file.
4960
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
4962
ControlFile->state = DB_SHUTDOWNED;
4963
ControlFile->prevCheckPoint = ControlFile->checkPoint;
4964
ControlFile->checkPoint = ProcLastRecPtr;
4965
ControlFile->checkPointCopy = checkPoint;
4966
ControlFile->time = time(NULL);
4967
UpdateControlFile();
4968
LWLockRelease(ControlFileLock);
4971
* We are now done with critical updates; no need for system panic if
4972
* we have trouble while fooling with offline log segments.
4977
* Delete offline log files (those no longer needed even for previous
4980
if (_logId || _logSeg)
4982
PrevLogSeg(_logId, _logSeg);
4983
MoveOfflineLogs(_logId, _logSeg, recptr,
4984
&nsegsremoved, &nsegsrecycled);
4988
* Make more log segments if needed. (Do this after deleting offline
4989
* log segments, to avoid having peak disk space usage higher than
4993
nsegsadded = PreallocXlogFiles(recptr);
4996
* Truncate pg_subtrans if possible. We can throw away all data
4997
* before the oldest XMIN of any running transaction. No future
4998
* transaction will attempt to reference any pg_subtrans entry older
4999
* than that (see Asserts in subtrans.c). During recovery, though, we
5000
* mustn't do this because StartupSUBTRANS hasn't been called yet.
5003
TruncateSUBTRANS(GetOldestXmin(true));
5007
(errmsg("checkpoint complete; %d transaction log file(s) added, %d removed, %d recycled",
5008
nsegsadded, nsegsremoved, nsegsrecycled)));
5010
LWLockRelease(CheckpointLock);
5014
* Write a NEXTOID log record
5017
XLogPutNextOid(Oid nextOid)
5021
rdata.buffer = InvalidBuffer;
5022
rdata.data = (char *) (&nextOid);
5023
rdata.len = sizeof(Oid);
5025
(void) XLogInsert(RM_XLOG_ID, XLOG_NEXTOID, &rdata);
5029
* XLOG resource manager's routines
5032
xlog_redo(XLogRecPtr lsn, XLogRecord *record)
5034
uint8 info = record->xl_info & ~XLR_INFO_MASK;
5036
if (info == XLOG_NEXTOID)
5040
memcpy(&nextOid, XLogRecGetData(record), sizeof(Oid));
5041
if (ShmemVariableCache->nextOid < nextOid)
5043
ShmemVariableCache->nextOid = nextOid;
5044
ShmemVariableCache->oidCount = 0;
5047
else if (info == XLOG_CHECKPOINT_SHUTDOWN)
5049
CheckPoint checkPoint;
5051
memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint));
5052
/* In a SHUTDOWN checkpoint, believe the counters exactly */
5053
ShmemVariableCache->nextXid = checkPoint.nextXid;
5054
ShmemVariableCache->nextOid = checkPoint.nextOid;
5055
ShmemVariableCache->oidCount = 0;
5058
* TLI may change in a shutdown checkpoint, but it shouldn't
5061
if (checkPoint.ThisTimeLineID != ThisTimeLineID)
5063
if (checkPoint.ThisTimeLineID < ThisTimeLineID ||
5064
!list_member_int(expectedTLIs,
5065
(int) checkPoint.ThisTimeLineID))
5067
(errmsg("unexpected timeline ID %u (after %u) in checkpoint record",
5068
checkPoint.ThisTimeLineID, ThisTimeLineID)));
5069
/* Following WAL records should be run with new TLI */
5070
ThisTimeLineID = checkPoint.ThisTimeLineID;
5073
else if (info == XLOG_CHECKPOINT_ONLINE)
5075
CheckPoint checkPoint;
5077
memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint));
5078
/* In an ONLINE checkpoint, treat the counters like NEXTOID */
5079
if (TransactionIdPrecedes(ShmemVariableCache->nextXid,
5080
checkPoint.nextXid))
5081
ShmemVariableCache->nextXid = checkPoint.nextXid;
5082
if (ShmemVariableCache->nextOid < checkPoint.nextOid)
5084
ShmemVariableCache->nextOid = checkPoint.nextOid;
5085
ShmemVariableCache->oidCount = 0;
5087
/* TLI should not change in an on-line checkpoint */
5088
if (checkPoint.ThisTimeLineID != ThisTimeLineID)
5090
(errmsg("unexpected timeline ID %u (should be %u) in checkpoint record",
5091
checkPoint.ThisTimeLineID, ThisTimeLineID)));
5096
xlog_undo(XLogRecPtr lsn, XLogRecord *record)
5101
xlog_desc(char *buf, uint8 xl_info, char *rec)
5103
uint8 info = xl_info & ~XLR_INFO_MASK;
5105
if (info == XLOG_CHECKPOINT_SHUTDOWN ||
5106
info == XLOG_CHECKPOINT_ONLINE)
5108
CheckPoint *checkpoint = (CheckPoint *) rec;
5110
sprintf(buf + strlen(buf), "checkpoint: redo %X/%X; undo %X/%X; "
5111
"tli %u; xid %u; oid %u; %s",
5112
checkpoint->redo.xlogid, checkpoint->redo.xrecoff,
5113
checkpoint->undo.xlogid, checkpoint->undo.xrecoff,
5114
checkpoint->ThisTimeLineID, checkpoint->nextXid,
5115
checkpoint->nextOid,
5116
(info == XLOG_CHECKPOINT_SHUTDOWN) ? "shutdown" : "online");
5118
else if (info == XLOG_NEXTOID)
5122
memcpy(&nextOid, rec, sizeof(Oid));
5123
sprintf(buf + strlen(buf), "nextOid: %u", nextOid);
5126
strcat(buf, "UNKNOWN");
5132
xlog_outrec(char *buf, XLogRecord *record)
5137
sprintf(buf + strlen(buf), "prev %X/%X; xid %u",
5138
record->xl_prev.xlogid, record->xl_prev.xrecoff,
5141
for (i = 0, bkpb = 0; i < XLR_MAX_BKP_BLOCKS; i++)
5143
if (!(record->xl_info & (XLR_SET_BKP_BLOCK(i))))
5149
sprintf(buf + strlen(buf), "; bkpb %d", bkpb);
5151
sprintf(buf + strlen(buf), ": %s",
5152
RmgrTable[record->xl_rmid].rm_name);
5154
#endif /* WAL_DEBUG */
5161
assign_xlog_sync_method(const char *method, bool doit, GucSource source)
5163
int new_sync_method;
5166
#ifndef FSYNC_IS_WRITE_THROUGH
5167
if (pg_strcasecmp(method, "fsync") == 0)
5169
/* Win32 fsync() == _commit(), which writes through a write cache */
5170
if (pg_strcasecmp(method, "fsync_writethrough") == 0)
5173
new_sync_method = SYNC_METHOD_FSYNC;
5176
#ifdef HAVE_FDATASYNC
5177
else if (pg_strcasecmp(method, "fdatasync") == 0)
5179
new_sync_method = SYNC_METHOD_FDATASYNC;
5183
#ifdef OPEN_SYNC_FLAG
5184
else if (pg_strcasecmp(method, "open_sync") == 0)
5186
new_sync_method = SYNC_METHOD_OPEN;
5187
new_sync_bit = OPEN_SYNC_FLAG;
5190
#ifdef OPEN_DATASYNC_FLAG
5191
else if (pg_strcasecmp(method, "open_datasync") == 0)
5193
new_sync_method = SYNC_METHOD_OPEN;
5194
new_sync_bit = OPEN_DATASYNC_FLAG;
5203
if (sync_method != new_sync_method || open_sync_bit != new_sync_bit)
5206
* To ensure that no blocks escape unsynced, force an fsync on the
5207
* currently open log segment (if any). Also, if the open flag is
5208
* changing, close the log file so it will be reopened (with new
5209
* flag bit) at next use.
5211
if (openLogFile >= 0)
5213
if (pg_fsync(openLogFile) != 0)
5215
(errcode_for_file_access(),
5216
errmsg("could not fsync log file %u, segment %u: %m",
5217
openLogId, openLogSeg)));
5218
if (open_sync_bit != new_sync_bit)
5220
if (close(openLogFile))
5222
(errcode_for_file_access(),
5223
errmsg("could not close log file %u, segment %u: %m",
5224
openLogId, openLogSeg)));
5228
sync_method = new_sync_method;
5229
open_sync_bit = new_sync_bit;
5237
* Issue appropriate kind of fsync (if any) on the current XLOG output file
5240
issue_xlog_fsync(void)
5242
switch (sync_method)
5244
case SYNC_METHOD_FSYNC:
5245
if (pg_fsync(openLogFile) != 0)
5247
(errcode_for_file_access(),
5248
errmsg("could not fsync log file %u, segment %u: %m",
5249
openLogId, openLogSeg)));
5251
#ifdef HAVE_FDATASYNC
5252
case SYNC_METHOD_FDATASYNC:
5253
if (pg_fdatasync(openLogFile) != 0)
5255
(errcode_for_file_access(),
5256
errmsg("could not fdatasync log file %u, segment %u: %m",
5257
openLogId, openLogSeg)));
5260
case SYNC_METHOD_OPEN:
5261
/* write synced it already */
5264
elog(PANIC, "unrecognized wal_sync_method: %d", sync_method);
5271
* pg_start_backup: set up for taking an on-line backup dump
5273
* Essentially what this does is to create a backup label file in $PGDATA,
5274
* where it will be archived as part of the backup dump. The label file
5275
* contains the user-supplied label string (typically this would be used
5276
* to tell where the backup dump will be stored) and the starting time and
5277
* starting WAL offset for the dump.
5280
pg_start_backup(PG_FUNCTION_ARGS)
5282
text *backupid = PG_GETARG_TEXT_P(0);
5285
XLogRecPtr checkpointloc;
5286
XLogRecPtr startpoint;
5289
char labelfilepath[MAXPGPATH];
5290
char xlogfilename[MAXFNAMELEN];
5293
struct stat stat_buf;
5298
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
5299
(errmsg("must be superuser to run a backup"))));
5301
if (!XLogArchivingActive())
5303
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5304
(errmsg("WAL archiving is not active"),
5305
(errhint("archive_command must be defined before "
5306
"online backups can be made safely.")))));
5308
backupidstr = DatumGetCString(DirectFunctionCall1(textout,
5309
PointerGetDatum(backupid)));
5312
* Force a CHECKPOINT. This is not strictly necessary, but it seems
5313
* like a good idea to minimize the amount of past WAL needed to use
5314
* the backup. Also, this guarantees that two successive backup runs
5315
* will have different checkpoint positions and hence different
5316
* history file names, even if nothing happened in between.
5318
RequestCheckpoint(true);
5321
* Now we need to fetch the checkpoint record location, and also its
5322
* REDO pointer. The oldest point in WAL that would be needed to
5323
* restore starting from the checkpoint is precisely the REDO pointer.
5325
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
5326
checkpointloc = ControlFile->checkPoint;
5327
startpoint = ControlFile->checkPointCopy.redo;
5328
LWLockRelease(ControlFileLock);
5330
XLByteToSeg(startpoint, _logId, _logSeg);
5331
XLogFileName(xlogfilename, ThisTimeLineID, _logId, _logSeg);
5334
* We deliberately use strftime/localtime not the src/timezone
5335
* functions, so that backup labels will consistently be recorded in
5336
* the same timezone regardless of TimeZone setting. This matches
5337
* elog.c's practice.
5339
stamp_time = time(NULL);
5340
strftime(strfbuf, sizeof(strfbuf),
5341
"%Y-%m-%d %H:%M:%S %Z",
5342
localtime(&stamp_time));
5345
* Check for existing backup label --- implies a backup is already
5348
snprintf(labelfilepath, MAXPGPATH, "%s/backup_label", DataDir);
5349
if (stat(labelfilepath, &stat_buf) != 0)
5351
if (errno != ENOENT)
5353
(errcode_for_file_access(),
5354
errmsg("could not stat file \"%s\": %m",
5359
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5360
errmsg("a backup is already in progress"),
5361
errhint("If you're sure there is no backup in progress, remove file \"%s\" and try again.",
5365
* Okay, write the file
5367
fp = AllocateFile(labelfilepath, "w");
5370
(errcode_for_file_access(),
5371
errmsg("could not create file \"%s\": %m",
5373
fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n",
5374
startpoint.xlogid, startpoint.xrecoff, xlogfilename);
5375
fprintf(fp, "CHECKPOINT LOCATION: %X/%X\n",
5376
checkpointloc.xlogid, checkpointloc.xrecoff);
5377
fprintf(fp, "START TIME: %s\n", strfbuf);
5378
fprintf(fp, "LABEL: %s\n", backupidstr);
5379
if (fflush(fp) || ferror(fp) || FreeFile(fp))
5381
(errcode_for_file_access(),
5382
errmsg("could not write file \"%s\": %m",
5386
* We're done. As a convenience, return the starting WAL offset.
5388
snprintf(xlogfilename, sizeof(xlogfilename), "%X/%X",
5389
startpoint.xlogid, startpoint.xrecoff);
5390
result = DatumGetTextP(DirectFunctionCall1(textin,
5391
CStringGetDatum(xlogfilename)));
5392
PG_RETURN_TEXT_P(result);
5396
* pg_stop_backup: finish taking an on-line backup dump
5398
* We remove the backup label file created by pg_start_backup, and instead
5399
* create a backup history file in pg_xlog (whence it will immediately be
5400
* archived). The backup history file contains the same info found in
5401
* the label file, plus the backup-end time and WAL offset.
5404
pg_stop_backup(PG_FUNCTION_ARGS)
5407
XLogCtlInsert *Insert = &XLogCtl->Insert;
5408
XLogRecPtr startpoint;
5409
XLogRecPtr stoppoint;
5412
char labelfilepath[MAXPGPATH];
5413
char histfilepath[MAXPGPATH];
5414
char startxlogfilename[MAXFNAMELEN];
5415
char stopxlogfilename[MAXFNAMELEN];
5425
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
5426
(errmsg("must be superuser to run a backup"))));
5429
* Get the current end-of-WAL position; it will be unsafe to use this
5430
* dump to restore to a point in advance of this time.
5432
LWLockAcquire(WALInsertLock, LW_EXCLUSIVE);
5433
INSERT_RECPTR(stoppoint, Insert, Insert->curridx);
5434
LWLockRelease(WALInsertLock);
5436
XLByteToSeg(stoppoint, _logId, _logSeg);
5437
XLogFileName(stopxlogfilename, ThisTimeLineID, _logId, _logSeg);
5440
* We deliberately use strftime/localtime not the src/timezone
5441
* functions, so that backup labels will consistently be recorded in
5442
* the same timezone regardless of TimeZone setting. This matches
5443
* elog.c's practice.
5445
stamp_time = time(NULL);
5446
strftime(strfbuf, sizeof(strfbuf),
5447
"%Y-%m-%d %H:%M:%S %Z",
5448
localtime(&stamp_time));
5451
* Open the existing label file
5453
snprintf(labelfilepath, MAXPGPATH, "%s/backup_label", DataDir);
5454
lfp = AllocateFile(labelfilepath, "r");
5457
if (errno != ENOENT)
5459
(errcode_for_file_access(),
5460
errmsg("could not read file \"%s\": %m",
5463
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5464
errmsg("a backup is not in progress")));
5468
* Read and parse the START WAL LOCATION line (this code is pretty
5469
* crude, but we are not expecting any variability in the file
5472
if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %24s)%c",
5473
&startpoint.xlogid, &startpoint.xrecoff, startxlogfilename,
5474
&ch) != 4 || ch != '\n')
5476
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5477
errmsg("invalid data in file \"%s\"", labelfilepath)));
5480
* Write the backup history file
5482
XLByteToSeg(startpoint, _logId, _logSeg);
5483
BackupHistoryFilePath(histfilepath, ThisTimeLineID, _logId, _logSeg,
5484
startpoint.xrecoff % XLogSegSize);
5485
fp = AllocateFile(histfilepath, "w");
5488
(errcode_for_file_access(),
5489
errmsg("could not create file \"%s\": %m",
5491
fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n",
5492
startpoint.xlogid, startpoint.xrecoff, startxlogfilename);
5493
fprintf(fp, "STOP WAL LOCATION: %X/%X (file %s)\n",
5494
stoppoint.xlogid, stoppoint.xrecoff, stopxlogfilename);
5495
/* transfer remaining lines from label to history file */
5496
while ((ich = fgetc(lfp)) != EOF)
5498
fprintf(fp, "STOP TIME: %s\n", strfbuf);
5499
if (fflush(fp) || ferror(fp) || FreeFile(fp))
5501
(errcode_for_file_access(),
5502
errmsg("could not write file \"%s\": %m",
5506
* Close and remove the backup label file
5508
if (ferror(lfp) || FreeFile(lfp))
5510
(errcode_for_file_access(),
5511
errmsg("could not read file \"%s\": %m",
5513
if (unlink(labelfilepath) != 0)
5515
(errcode_for_file_access(),
5516
errmsg("could not remove file \"%s\": %m",
5520
* Notify archiver that history file may be archived immediately
5522
if (XLogArchivingActive())
5524
BackupHistoryFileName(histfilepath, ThisTimeLineID, _logId, _logSeg,
5525
startpoint.xrecoff % XLogSegSize);
5526
XLogArchiveNotify(histfilepath);
5530
* We're done. As a convenience, return the ending WAL offset.
5532
snprintf(stopxlogfilename, sizeof(stopxlogfilename), "%X/%X",
5533
stoppoint.xlogid, stoppoint.xrecoff);
5534
result = DatumGetTextP(DirectFunctionCall1(textin,
5535
CStringGetDatum(stopxlogfilename)));
5536
PG_RETURN_TEXT_P(result);
5540
* read_backup_label: check to see if a backup_label file is present
5542
* If we see a backup_label during recovery, we assume that we are recovering
5543
* from a backup dump file, and we therefore roll forward from the checkpoint
5544
* identified by the label file, NOT what pg_control says. This avoids the
5545
* problem that pg_control might have been archived one or more checkpoints
5546
* later than the start of the dump, and so if we rely on it as the start
5547
* point, we will fail to restore a consistent database state.
5549
* We also attempt to retrieve the corresponding backup history file.
5550
* If successful, set recoveryMinXlogOffset to constrain valid PITR stopping
5553
* Returns TRUE if a backup_label was found (and fills the checkpoint
5554
* location into *checkPointLoc); returns FALSE if not.
5557
read_backup_label(XLogRecPtr *checkPointLoc)
5559
XLogRecPtr startpoint;
5560
XLogRecPtr stoppoint;
5561
char labelfilepath[MAXPGPATH];
5562
char histfilename[MAXFNAMELEN];
5563
char histfilepath[MAXPGPATH];
5564
char startxlogfilename[MAXFNAMELEN];
5565
char stopxlogfilename[MAXFNAMELEN];
5574
* See if label file is present
5576
snprintf(labelfilepath, MAXPGPATH, "%s/backup_label", DataDir);
5577
lfp = AllocateFile(labelfilepath, "r");
5580
if (errno != ENOENT)
5582
(errcode_for_file_access(),
5583
errmsg("could not read file \"%s\": %m",
5585
return false; /* it's not there, all is fine */
5589
* Read and parse the START WAL LOCATION and CHECKPOINT lines (this
5590
* code is pretty crude, but we are not expecting any variability in
5593
if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %08X%16s)%c",
5594
&startpoint.xlogid, &startpoint.xrecoff, &tli,
5595
startxlogfilename, &ch) != 5 || ch != '\n')
5597
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5598
errmsg("invalid data in file \"%s\"", labelfilepath)));
5599
if (fscanf(lfp, "CHECKPOINT LOCATION: %X/%X%c",
5600
&checkPointLoc->xlogid, &checkPointLoc->xrecoff,
5601
&ch) != 3 || ch != '\n')
5603
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5604
errmsg("invalid data in file \"%s\"", labelfilepath)));
5605
if (ferror(lfp) || FreeFile(lfp))
5607
(errcode_for_file_access(),
5608
errmsg("could not read file \"%s\": %m",
5612
* Try to retrieve the backup history file (no error if we can't)
5614
XLByteToSeg(startpoint, _logId, _logSeg);
5615
BackupHistoryFileName(histfilename, tli, _logId, _logSeg,
5616
startpoint.xrecoff % XLogSegSize);
5618
if (InArchiveRecovery)
5619
RestoreArchivedFile(histfilepath, histfilename, "RECOVERYHISTORY", 0);
5621
BackupHistoryFilePath(histfilepath, tli, _logId, _logSeg,
5622
startpoint.xrecoff % XLogSegSize);
5624
fp = AllocateFile(histfilepath, "r");
5628
* Parse history file to identify stop point.
5630
if (fscanf(fp, "START WAL LOCATION: %X/%X (file %24s)%c",
5631
&startpoint.xlogid, &startpoint.xrecoff, startxlogfilename,
5632
&ch) != 4 || ch != '\n')
5634
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5635
errmsg("invalid data in file \"%s\"", histfilename)));
5636
if (fscanf(fp, "STOP WAL LOCATION: %X/%X (file %24s)%c",
5637
&stoppoint.xlogid, &stoppoint.xrecoff, stopxlogfilename,
5638
&ch) != 4 || ch != '\n')
5640
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5641
errmsg("invalid data in file \"%s\"", histfilename)));
5642
recoveryMinXlogOffset = stoppoint;
5643
if (ferror(fp) || FreeFile(fp))
5645
(errcode_for_file_access(),
5646
errmsg("could not read file \"%s\": %m",
5654
* remove_backup_label: remove any extant backup_label after successful
5655
* recovery. Once we have completed the end-of-recovery checkpoint there
5656
* is no reason to have to replay from the start point indicated by the
5657
* label (and indeed we'll probably have removed/recycled the needed WAL
5658
* segments), so remove the label to prevent trouble in later crash recoveries.
5661
remove_backup_label(void)
5663
char labelfilepath[MAXPGPATH];
5665
snprintf(labelfilepath, MAXPGPATH, "%s/backup_label", DataDir);
5666
if (unlink(labelfilepath) != 0)
5667
if (errno != ENOENT)
5669
(errcode_for_file_access(),
5670
errmsg("could not remove file \"%s\": %m",
added
removed
src/backend/access/transam/xlog.c
