Re: GIN logging GIN_SEGMENT_UNMODIFIED actions? - Mailing list pgsql-hackers

On Tue, May 10, 2016 at 9:57 PM, Alexander Korotkov
<a.korotkov@postgrespro.ru> wrote:
> Hi!
>
> On Mon, May 9, 2016 at 10:46 PM, Andres Freund <andres@anarazel.de> wrote:
>>
>> trying to debug something I saw the following in pg_xlogdump output:
>>
>> rmgr: Gin         len (rec/tot):      0/   274, tx:          0, lsn:
>> 1C/DF28AEB0, prev 1C/DF289858, desc: VACUUM_DATA_LEAF_PAGE  3 segments: 5
>> unknown action 0 ???, blkref #0: rel 1663/16384/16435 blk 310982
>>
>> note the "segments: 5 unknown action 0 ???" bit.  That doesn't seem
>> right, given:
>> #define GIN_SEGMENT_UNMODIFIED  0               /* no action (not used in
>> WAL records) */
>
>
> I've checked GIN code.  Have no idea of how such wal record could be
> generated...

I encountered the same issue when executing the following queries and
running pg_xlogdump.

CREATE EXTENSION pg_trgm;
CREATE TABLE test (col1 TEXT);
CREATE INDEX testidx ON test USING gin (col1 gin_trgm_ops) WITH
(fastupdate = off);
INSERT INTO test SELECT 'ABCDE' FROM generate_series(1,10000);
DELETE FROM test;
VACUUM test;

$ pg_xlogdump data/pg_xlog/000000010000000000000004 | grep Gin | grep action
rmgr: Gin         len (rec/tot):      0/    88, tx:          0, lsn:
0/04A4B468, prev 0/04A4B438, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
11
rmgr: Gin         len (rec/tot):      0/    78, tx:          0, lsn:
0/04A4B4C0, prev 0/04A4B468, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
10
rmgr: Gin         len (rec/tot):      0/    88, tx:          0, lsn:
0/04A4B510, prev 0/04A4B4C0, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
13
rmgr: Gin         len (rec/tot):      0/    78, tx:          0, lsn:
0/04A4B568, prev 0/04A4B510, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
12
rmgr: Gin         len (rec/tot):      0/    88, tx:          0, lsn:
0/04A4B5B8, prev 0/04A4B568, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
15
rmgr: Gin         len (rec/tot):      0/    78, tx:          0, lsn:
0/04A4B610, prev 0/04A4B5B8, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
14
rmgr: Gin         len (rec/tot):      0/    88, tx:          0, lsn:
0/04A4B660, prev 0/04A4B610, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
17
rmgr: Gin         len (rec/tot):      0/    78, tx:          0, lsn:
0/04A4B6B8, prev 0/04A4B660, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
16
rmgr: Gin         len (rec/tot):      0/    88, tx:          0, lsn:
0/04A4B708, prev 0/04A4B6B8, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
19
rmgr: Gin         len (rec/tot):      0/    78, tx:          0, lsn:
0/04A4B760, prev 0/04A4B708, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
18
rmgr: Gin         len (rec/tot):      0/    88, tx:          0, lsn:
0/04A4B7B0, prev 0/04A4B760, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
21
rmgr: Gin         len (rec/tot):      0/    78, tx:          0, lsn:
0/04A4B808, prev 0/04A4B7B0, desc: VACUUM_DATA_LEAF_PAGE  1663
segments: 0 unknown action 0 ???, blkref #0: rel 1663/13286/16455 blk
20

Regards,

-- 
Fujii Masao