2
-- Test large object support
5
CREATE TABLE lotest_stash_values (loid oid, fd integer);
6
-- lo_creat(mode integer) returns oid
7
-- The mode arg to lo_creat is unused, some vestigal holdover from ancient times
8
-- returns the large object id
9
INSERT INTO lotest_stash_values (loid) SELECT lo_creat(42);
10
-- NOTE: large objects require transactions
12
-- lo_open(lobjId oid, mode integer) returns integer
13
-- The mode parameter to lo_open uses two constants:
15
-- INV_WRITE = 0x40000
16
-- The return value is a file descriptor-like value which remains valid for the
18
UPDATE lotest_stash_values SET fd = lo_open(loid, CAST(x'20000' | x'40000' AS integer));
19
-- loread/lowrite names are wonky, different from other functions which are lo_*
20
-- lowrite(fd integer, data bytea) returns integer
21
-- the integer is the number of bytes written
23
Whose woods these are I think I know,
24
His house is in the village though.
25
He will not see me stopping here,
26
To watch his woods fill up with snow.
28
My little horse must think it queer,
29
To stop without a farmhouse near,
30
Between the woods and frozen lake,
31
The darkest evening of the year.
33
He gives his harness bells a shake,
34
To ask if there is some mistake.
35
The only other sound''s the sweep,
36
Of easy wind and downy flake.
38
The woods are lovely, dark and deep,
39
But I have promises to keep,
40
And miles to go before I sleep,
41
And miles to go before I sleep.
44
') FROM lotest_stash_values;
50
-- lo_close(fd integer) returns integer
51
-- return value is 0 for success, or <0 for error (actually only -1, but...)
52
SELECT lo_close(fd) FROM lotest_stash_values;
61
UPDATE lotest_stash_values SET fd=lo_open(loid, CAST(x'20000' | x'40000' AS integer));
62
-- lo_lseek(fd integer, offset integer, whence integer) returns integer
63
-- offset is in bytes, whence is one of three values:
64
-- SEEK_SET (= 0) meaning relative to beginning
65
-- SEEK_CUR (= 1) meaning relative to current position
66
-- SEEK_END (= 2) meaning relative to end (offset better be negative)
67
-- returns current position in file
68
SELECT lo_lseek(fd, 422, 0) FROM lotest_stash_values;
74
-- loread/lowrite names are wonky, different from other functions which are lo_*
75
-- loread(fd integer, len integer) returns bytea
76
SELECT loread(fd, 35) FROM lotest_stash_values;
78
-------------------------------------
79
The woods are lovely, dark and deep
82
SELECT lo_lseek(fd, -19, 1) FROM lotest_stash_values;
88
SELECT lowrite(fd, 'n') FROM lotest_stash_values;
94
SELECT lo_tell(fd) FROM lotest_stash_values;
100
SELECT lo_lseek(fd, -156, 2) FROM lotest_stash_values;
106
SELECT loread(fd, 35) FROM lotest_stash_values;
108
-------------------------------------
109
The woods are lonely, dark and deep
112
SELECT lo_close(fd) FROM lotest_stash_values;
119
-- Test resource management
121
SELECT lo_open(loid, x'40000'::int) from lotest_stash_values;
130
UPDATE lotest_stash_values SET fd=lo_open(loid, CAST(x'20000' | x'40000' AS integer));
131
SELECT lo_truncate(fd, 10) FROM lotest_stash_values;
137
SELECT loread(fd, 15) FROM lotest_stash_values;
143
SELECT lo_truncate(fd, 10000) FROM lotest_stash_values;
149
SELECT loread(fd, 10) FROM lotest_stash_values;
151
------------------------------------------
152
\000\000\000\000\000\000\000\000\000\000
155
SELECT lo_lseek(fd, 0, 2) FROM lotest_stash_values;
161
SELECT lo_tell(fd) FROM lotest_stash_values;
167
SELECT lo_truncate(fd, 5000) FROM lotest_stash_values;
173
SELECT lo_lseek(fd, 0, 2) FROM lotest_stash_values;
179
SELECT lo_tell(fd) FROM lotest_stash_values;
185
SELECT lo_close(fd) FROM lotest_stash_values;
192
-- lo_unlink(lobjId oid) returns integer
193
-- return value appears to always be 1
194
SELECT lo_unlink(loid) from lotest_stash_values;
200
TRUNCATE lotest_stash_values;
201
INSERT INTO lotest_stash_values (loid) SELECT lo_import('@abs_srcdir@/data/tenk.data');
203
UPDATE lotest_stash_values SET fd=lo_open(loid, CAST(x'20000' | x'40000' AS integer));
204
-- with the default BLKSZ, LOBLKSZ = 2048, so this positions us for a block
206
SELECT lo_lseek(fd, 2030, 0) FROM lotest_stash_values;
212
-- this should get half of the value from page 0 and half from page 1 of the
214
SELECT loread(fd, 36) FROM lotest_stash_values;
216
-----------------------------------------------------------------
217
AAA\011FBAAAA\011VVVVxx\0122513\01132\0111\0111\0113\01113\0111
220
SELECT lo_tell(fd) FROM lotest_stash_values;
226
SELECT lo_lseek(fd, -26, 1) FROM lotest_stash_values;
232
SELECT lowrite(fd, 'abcdefghijklmnop') FROM lotest_stash_values;
238
SELECT lo_lseek(fd, 2030, 0) FROM lotest_stash_values;
244
SELECT loread(fd, 36) FROM lotest_stash_values;
246
-----------------------------------------------------
247
AAA\011FBAAAAabcdefghijklmnop1\0111\0113\01113\0111
250
SELECT lo_close(fd) FROM lotest_stash_values;
257
SELECT lo_export(loid, '@abs_builddir@/results/lotest.txt') FROM lotest_stash_values;
263
\lo_import 'results/lotest.txt'
264
\set newloid :LASTOID
265
-- just make sure \lo_export does not barf
266
\lo_export :newloid 'results/lotest2.txt'
267
-- This is a hack to test that export/import are reversible
268
-- This uses knowledge about the inner workings of large object mechanism
269
-- which should not be used outside it. This makes it a HACK
270
SELECT pageno, data FROM pg_largeobject WHERE loid = (SELECT loid from lotest_stash_values)
272
SELECT pageno, data FROM pg_largeobject WHERE loid = :newloid;
277
SELECT lo_unlink(loid) FROM lotest_stash_values;
284
TRUNCATE lotest_stash_values;