Horton

Re: backup manifests

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: David Steele <david@pgmasters.net>, Noah Misch <noah@leadboat.com>, Stephen Frost <sfrost@snowman.net>, Amit Kapila <amit.kapila16@gmail.com>, Suraj Kharage <suraj.kharage@enterprisedb.com>, tushar <tushar.ahuja@enterprisedb.com>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, Rushabh Lathia <rushabh.lathia@gmail.com>, Tels <nospam-pg-abuse@bloodgate.com>, Andrew Dunstan <andrew.dunstan@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Jeevan Chalke <jeevan.chalke@enterprisedb.com>, vignesh C <vignesh21@gmail.com>
Date: 2020-04-02T19:42:48Z
Lists: pgsql-hackers

Commits

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

  1. Try to avoid compiler warnings in optimized builds.

  2. Fix option related issues in pg_verifybackup.

  3. Add index term for backup manifest in documentation.

  4. Code review for backup manifest.

  5. Document the backup manifest file format.

  6. Fix typo in pg_validatebackup documentation.

  7. Exclude backup_manifest file that existed in database, from BASE_BACKUP.

  8. Msys2 tweaks for pg_validatebackup corruption test

  9. Fix resource management bug with replication=database.

  10. Be more careful about time_t vs. pg_time_t in basebackup.c.

  11. pg_validatebackup: Fix 'make clean' to remove tmp_check.

  12. pg_validatebackup: Also use perl2host in TAP tests.

  13. Generate backup manifests for base backups, and validate them.

  14. Add checksum helper functions.

  15. pg_waldump: Add a --quiet option.

  16. Catversion bump for b9b408c48724

  17. pg_basebackup: Refactor code for reading COPY and tar data.

  18. Use a ResourceOwner to track buffer pins in all cases.

  19. Use ARMv8 CRC instructions where available.

  20. Logical replication support for initial data copy

  21. Use Intel SSE 4.2 CRC instructions where available.

  22. Switch to CRC-32C in WAL and other places.

  23. Remove support for 64-bit CRC.

  24. Change CRCs in WAL records from 64bit to 32bit for performance reasons.

On Thu, Apr 2, 2020 at 2:55 PM Robert Haas <robertmhaas@gmail.com> wrote:
> On Thu, Apr 2, 2020 at 2:23 PM Andres Freund <andres@anarazel.de> wrote:
> > > That might make the window fairly wide on normal systems, but I'm not
> > > sure about Raspberry Pi BF members or things running
> > > CLOBBER_CACHE_ALWAYS/RECURSIVELY. I guess I could try it.
> >
> > You can set checkpoint_timeout to be a day. If that's not enough, well,
> > then I think we have other problems.
>
> I'm not sure that's the only issue here, but I'll try it.

I ran into a few problems here. In trying to set this up manually, I
always began with the following steps:

====
# (1) create cluster
initdb

# (2) add to configuration file
log_checkpoints=on
checkpoint_timeout=1d
checkpoint_completion_target=0.99

# (3) fire it up
postgres
createdb
====

If at this point I do "pg_basebackup -D pgslave -R -c spread", it
completes within a few seconds anyway, because there's basically
nothing dirty, and no matter how slowly you write out no data, it's
still pretty quick. If I run "pgbench -i" first, and then
"pg_basebackup -D pgslave -R -c spread", it hangs, apparently
essentially forever, because now the checkpoint has something to do,
and it does it super-slowly, and "psql -c checkpoint" makes it finish
immediately. However, this experiment isn't testing quite the right
thing, because what I actually need is a slow backup off of a
cascading standby, so that I have time to promote the parent standby
before the backup completes. I tried continuing like this:

====
# (4) set up standby
pg_basebackup -D pgslave -R
postgres -D pgslave -c port=5433

# (5) set up cascading standby
pg_basebackup -D pgslave2 -d port=5433 -R
postgres -c port=5434 -D pgslave2

# (6) dirty some pages on the master
pgbench -i

# (7) start a backup of the cascading standby
pg_basebackup -D pgslave3 -d port=5434 -R -c spread
====

However, the pg_basebackup in the last step completes after only a few
seconds. If it were hanging, then I could continue with "pg_ctl
promote -D pgslave" and that might give me what I need, but that's not
what happens.

I suspect I'm not doing quite what you had in mind here... thoughts?

-- 
Robert Haas
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