Horton
Menu

Re: WIP: WAL prefetch (another approach)

Thomas Munro <thomas.munro@gmail.com>

View thread
From: Thomas Munro <thomas.munro@gmail.com>
To: Tomas Vondra <tomas.vondra@enterprisedb.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Stephen Frost <sfrost@snowman.net>, Andres Freund <andres@anarazel.de>, Jakub Wartak <Jakub.Wartak@tomtom.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Dmitry Dolgov <9erthalion6@gmail.com>, David Steele <david@pgmasters.net>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-04-21T23:16:17Z
Lists: pgsql-hackers 
On Thu, Apr 22, 2021 at 8:16 AM Thomas Munro <thomas.munro@gmail.com> wrote:
> That wasn't my plan, but I admit that the timing was non-ideal.  In
> any case, I'll dig into these failures and then consider options.
> More soon.

Yeah, this clearly needs more work.  xlogreader.c is difficult to work
with and I think we need to keep trying to improve it, but I made a
bad call here trying to combine this with other refactoring work up
against a deadline and I made some dumb mistakes.  I could of course
debug it in-tree, and I know that this has been an anticipated
feature.  Personally I think the right thing to do now is to revert it
and re-propose for 15 early in the cycle, supported with some better
testing infrastructure.

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