Re: BUG #17245: Index corruption involving deduplicated entries

On 29.10.2021 10:55, Kamigishi Rei wrote:
>> Do you have the log file(s) from between the 24th and now? That might 
>> give us
>> a good starting point for the LSN range to scan.
>
> There are multiple WAL log files, the first of them with the timestamp 
> of Oct 25 09:45.


The newly manifested issue is caught by pg_amcheck:

btree index "azurlane_wiki.mediawiki.page_main_title":
     ERROR:  item order invariant violated for index "page_main_title"
     DETAIL:  Lower index tid=(17,157) (points to heap tid=(540,5)) 
higher index tid=(17,158) (points to heap tid=(540,5)) page lsn=2/A019DD78.

The weird part about this is that the WAL archive does not seem to 
contain any data for 157 and 158 above (in 1663/19243/274869 blk 17). 
The last two entries are

rmgr: Btree       len (rec/tot):     53/  4885, tx:    2085600, lsn: 
2/A0195AE0, prev 2/A01943F0, desc: INSERT_LEAF off 155, blkref #0: rel 
1663/19243/274869 blk 17 FPW
rmgr: Btree       len (rec/tot):     72/    72, tx:    2085602, lsn: 
2/A019DD30, prev 2/A019DCF0, desc: INSERT_LEAF off 156, blkref #0: rel 
1663/19243/274869 blk 17

The WAL file in data14/pg_wal does not have anything related to 157 and 
158 for this filenode/blk as well.

-- 
K. R.