Horton

Re: backup manifests

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: David Steele <david@pgmasters.net>, 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: 2020-03-30T05:58:54Z
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 Sun, Mar 29, 2020 at 08:42:35PM -0400, Robert Haas wrote:
> On Sat, Mar 28, 2020 at 11:40 PM Noah Misch <noah@leadboat.com> wrote:
> > I think this functionality doesn't belong in its own program.  If you suspect
> > pg_basebackup or pg_restore will eventually gain the ability to merge
> > incremental backups into a recovery-ready base backup, I would put the
> > functionality in that program.  Otherwise, I would put it in pg_checksums.
> > For me, part of the friction here is that the program description indicates
> > general verification, but the actual functionality merely checks hashes on a
> > directory tree that happens to represent a PostgreSQL base backup.
> 
> Suraj's original patch made this part of pg_basebackup, but I didn't
> really like that, because I wanted it to have its own set of options.
> I still think all the options I've added are pretty useful ones, and I
> can think of other things somebody might want to do. It feels very
> uncomfortable to make pg_basebackup, or pg_checksums, take either
> options from set A and do thing X, or options from set B and do thing
> Y.

pg_checksums does already have that property, for what it's worth.  (More
specifically, certain options dictate the mode, and it reports an error if
another option is incompatible with the mode.)

> But it feels clear that the name pg_validatebackup is not going
> over very well with anyone. I think I should rename it to
> pg_validatemanifest.

Between those two, I would use "pg_validatebackup" if there's a fair chance it
will end up doing the pg_waldump check.  Otherwise, I would use
"pg_validatemanifest".  I still most prefer delivering this as a mode of an
existing program.

> > > +             parse->pathname = palloc(raw_length + 1);
> >
> > I don't see this freed anywhere; is it?  (It's useful to make peak memory
> > consumption not grow in proportion to the number of files backed up.)
> 
> We need the hash table to remain populated for the whole run time of
> the tool, because we're essentially doing a full join of the actual
> directory contents against the manifest contents. That's a bit
> unfortunate but it doesn't seem simple to improve. I think the only
> people who are really going to suffer are people who have an enormous
> pile of empty or nearly-empty relations. People who have large
> databases for the normal reason - i.e. a reasonable number of tables
> that hold a lot of data - will have manifests of very manageable size.

Okay.