Horton

Re: backup manifests

David Steele <david@pgmasters.net>

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From: David Steele <david@pgmasters.net>
To: Andres Freund <andres@anarazel.de>, Stephen Frost <sfrost@snowman.net>
Cc: Robert Haas <robertmhaas@gmail.com>, 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: 2020-03-27T22:33:51Z
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 3/27/20 6:07 PM, Andres Freund wrote:
> Hi,
> 
> On 2020-03-27 16:57:46 -0400, Stephen Frost wrote:
>> I really don't know what to say to this.  WAL is absolutely critical to
>> a backup being valid.  pgBackRest doesn't have a way to *just* validate
>> a backup today, unfortunately, but we're planning to support it in the
>> future and we will absolutely include in that validation checking all of
>> the WAL that's part of the backup.
> 
> Could you please address the fact that just about everybody uses base
> backups + later WAL to have a short data loss window? Integrating the
> WAL files necessary to make the base backup consistent doesn't achieve
> much if we can't verify the WAL files afterwards. And fairly obviously
> pg_basebackup can't do much about WAL created after its invocation.
> 
> Given that we need something separate to address that "verification
> hole", I don't see why it's useful to have a special case solution (or
> rather multiple ones, for stream and fetch) inside pg_basebackup.

There's a pretty big difference between not being able to play forward 
to the end of WAL and not being able to get the backup to restore to 
consistency at all.

The WAL that is generated during during the backup has special 
importance. Without it you have no backup at all.  It's the difference 
between *some* data loss and *total* data loss.

Regards,
-- 
-David
david@pgmasters.net