Horton

Re: Back-patch of: avoid multiple hard links to same WAL file after a crash

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Nathan Bossart <nathandbossart@gmail.com>, Andres Freund <andres@anarazel.de>, Robert Pang <robertpang@google.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, robertmhaas@gmail.com, pgsql-hackers@postgresql.org
Date: 2025-03-11T20:57:49Z
Lists: pgsql-hackers 
On Mon, Mar 10, 2025 at 02:25:28PM +0900, Michael Paquier wrote:
> On Thu, Mar 06, 2025 at 01:44:30PM -0600, Nathan Bossart wrote:
> > On Thu, Mar 06, 2025 at 11:30:13AM -0800, Noah Misch wrote:
> >> 1. Make v14 and v13 skip WAL recycling and preallocation during archive
> >>    recovery, like newer branches do.  I think that means back-patching the six
> >>    commits cc2c7d6~4 cc2c7d6~3 cc2c7d6~2 cc2c7d6~1 cc2c7d6 e36cbef.
> >> 
> >> 2. Revert 1f95181b44c843729caaa688f74babe9403b5850 and its v13 counterpart.
> >>    Avoid multiple hard links by making durable_rename_excl() first rename
> >>    oldfile to a temporary name.  (I haven't thought this through in detail.
> >>    It may not suffice.)
> >> 
> >> I'm leaning toward (1) at least enough to see how messy the back-patch would
> >> be, since I don't like risks of designing old-branch-specific solutions when
> >> v15/v16/v17 have a proven solution.  What else should we be thinking about
> >> before deciding?
> > 
> > I agree with first attempting a back-patch.  All of this stuff is from
> > 2021-2022, so it's had time to bake and is IMHO lower risk.

> Could it be possible for you to double-check and also run
> more tests if your enviroments help?

Thanks for crafting back-branch versions.  I've queued a task to confirm I get
the same result.  There's a test case I'll polish, too.

Commits

  1. Test restartpoints in archive recovery.

  2. Reset InstallXLogFileSegmentActive after walreceiver self-initiated exit.

  3. Skip WAL recycling and preallocation during archive recovery.

  4. Don't ERROR on PreallocXlogFiles() race condition.

  5. Revert "Add HINT for restartpoint race with KeepFileRestoredFromArchive()."

  6. Remove XLogFileInit() ability to unlink a pre-existing file.

  7. In XLogFileInit(), fix *use_existent postcondition to suit callers.

  8. Remove XLogFileInit() ability to skip ControlFileLock.

  9. Replace durable_rename_excl() by durable_rename(), take two

  10. Add HINT for restartpoint race with KeepFileRestoredFromArchive().

  11. Remove durable_rename_excl()

  12. Replace existing durable_rename_excl() calls with durable_rename()