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Re: WIP: WAL prefetch (another approach)

Tomas Vondra <tomas.vondra@2ndquadrant.com>

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From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Stephen Frost <sfrost@snowman.net>, Dmitry Dolgov <9erthalion6@gmail.com>, David Steele <david@pgmasters.net>, Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2020-09-01T14:18:26Z
Lists: pgsql-hackers 
On Wed, Sep 02, 2020 at 02:05:10AM +1200, Thomas Munro wrote:
>On Wed, Sep 2, 2020 at 1:14 AM Tomas Vondra
><tomas.vondra@2ndquadrant.com> wrote:
>> from the archive
>
>Ahh, so perhaps that's the key.
>

Maybe. For the record, the commands look like this:

archive_command = 'gzip -1 -c %p > /mnt/raid/wal-archive/%f.gz'

restore_command = 'gunzip -c /mnt/raid/wal-archive/%f.gz > %p.tmp && mv %p.tmp %p'

>> I've tested this applied on 6ca547cf75ef6e922476c51a3fb5e253eef5f1b6,
>> and the failure seems fairly similar to what I reported before, except
>> that now it happened right at the very beginning.
>
>Thanks, will see if I can work out why.  My newer version probably has
>the same problem.

OK.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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