Horton

Re: backup manifests

Stephen Frost <sfrost@snowman.net>

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From: Stephen Frost <sfrost@snowman.net>
To: Andres Freund <andres@anarazel.de>
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>, David Steele <david@pgmasters.net>, Andrew Dunstan <andrew.dunstan@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Jeevan Chalke <jeevan.chalke@enterprisedb.com>, vignesh C <vignesh21@gmail.com>
Date: 2020-03-27T22:09:10Z
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.

Greetings,

* Andres Freund (andres@anarazel.de) wrote:
> On 2020-03-27 17:44:07 -0400, Stephen Frost wrote:
> > * Andres Freund (andres@anarazel.de) wrote:
> > > On 2020-03-27 15:20:27 -0400, Robert Haas wrote:
> > > > On Fri, Mar 27, 2020 at 2:29 AM Andres Freund <andres@anarazel.de> wrote:
> > > > > Hm. Should this warn if the directory's permissions are set too openly
> > > > > (world writable?)?
> > > > 
> > > > I don't think so, but it's pretty clear that different people have
> > > > different ideas about what the scope of this tool ought to be, even in
> > > > this first version.
> > > 
> > > Yea. I don't have a strong opinion on this specific issue. I was mostly
> > > wondering because I've repeatedly seen people restore backups with world
> > > readable properties, and with that it's obviously possible for somebody
> > > else to change the contents after the checksum was computed.
> > 
> > For my 2c, at least, I don't think we need to check the directory
> > permissions, but I wouldn't object to including a warning if they're set
> > such that PG won't start.  I suppose +0 for "warn if they are such that
> > PG won't start".
> 
> I was thinking of that check not being just at the top-level, but in
> subdirectories too. It's easy to screw up the top and subdirectory
> permissions in different ways, e.g. when manually creating the database
> dir and then restoring a data directory directly into that.  IIRC
> postmaster doesn't check that at start.

Yeah, I'm pretty sure we don't check that at postmaster start..  which
also means that we'll start up just fine even if the perms on
subdirectories are odd or wrong, unless maybe we end up in a really odd
state where a directory is 000'd or something.

Of course..  this is all a mess when it comes to pg_basebackup, really,
as previously discussed elsewhere, because what permissions and such you
end up with actually depends on what *format* you use with
pg_basebackup- it's different between 'tar' format and 'plain' format.
That is, if you use 'tar' format, and then actually use 'tar' to
extract, you get one set of privs, but if you use 'plain', you get
something different.

I mean..  pgBackRest sets all perms to whatever is in the manifest on
restore (or delta), but this patch doesn't include the permissions on
files, or ownership (something pgBackRest also tries to set, if
possible, on restore), does it...?  Doesn't look like it on a quick
look.  So if we want to compare to pgBackRest then, yes, we should
include the permissions in the manifest and we should check that
everything in the manifest matches what's on the filesystem.

I don't think we should just compare all permissions or ownership with
some arbitrary idea of what we think they should be, even though if you
use pg_basebackup in 'plain' format, you actually end up with
differences, today, from what the source system has.  In my view, that
should actually be fixed, to the extent possible.

Thanks,

Stephen