Horton
Menu

Re: WIP: WAL prefetch (another approach)

Tom Lane <tgl@sss.pgh.pa.us>

View thread
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Michael Paquier <michael.paquier@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Stephen Frost <sfrost@snowman.net>, Alvaro Herrera <alvherre@2ndquadrant.com>, David Steele <david@pgmasters.net>, Dmitry Dolgov <9erthalion6@gmail.com>, Jakub Wartak <Jakub.Wartak@tomtom.com>, Tomas Vondra <tomas.vondra@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-04-29T03:39:38Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> I was now able to reproduce the problem again, and I'm afraid that the
> bug I hit is likely separate from Tom's.

Yeah, I think so --- the symptoms seem quite distinct.

My score so far today on the G4 is:

12 error-free regression test cycles on b3ee4c503

(plus one more with shared_buffers set to 16MB, on the strength
of your previous hunch --- didn't fail for me though)

HEAD failed on the second run with the same symptom as before:

2021-04-28 22:57:17.048 EDT [50479] FATAL:  inconsistent page found, rel 1663/58183/69545, forknum 0, blkno 696
2021-04-28 22:57:17.048 EDT [50479] CONTEXT:  WAL redo at 4/B72D408 for Heap/INSERT: off 77 flags 0x00; blkref #0: rel 1663/58183/69545, blk 696 FPW

This seems to me to be pretty strong evidence that I'm seeing *something*
real.  I'm currently trying to isolate a specific commit to pin it on.
A straight "git bisect" isn't going to work because so many people had
broken so many different things right around that date :-(, so it may
take awhile to get a good answer.

			regards, tom lane

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix recovery_prefetch docs.

  2. Prefetch data referenced by the WAL, take II.

  3. Add circular WAL decoding buffer, take II.

  4. Fix generation of ./INSTALL for the distribution tarball

  5. Revert recovery prefetching feature.

  6. Sync guc.c and postgresql.conf.sample with the SGML docs.

  7. Add information of total data processed to replication slot stats.

  8. Doc: Review for "Optionally prefetch referenced data in recovery."

  9. Add circular WAL decoding buffer.

  10. Optionally prefetch referenced data in recovery.

  11. Remove read_page callback from XLogReader.

  12. Provide ReadRecentBuffer() to re-pin buffers by ID.

  13. Provide recovery_init_sync_method=syncfs.

  14. Mark factorial operator, and postfix operators in general, as deprecated.

  15. Rationalize GetWalRcv{Write,Flush}RecPtr().

  16. Support PrefetchBuffer() in recovery.

  17. Prevent hard failures of standbys caused by recycled WAL segments