Horton

Re: avoid multiple hard links to same WAL file after a crash

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Robert Haas <robertmhaas@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2022-04-18T18:23:36Z
Lists: pgsql-hackers 
On Mon, Apr 18, 2022 at 04:48:35PM +0900, Michael Paquier wrote:
> Saying that, it would be nice to see durable_rename_excl() gone as it
> has created quite a bit of pain for us in the past years.

Yeah, I think this is the right thing to do.  Patch upthread [0].

For back-branches, I suspect we'll want to remove all uses of
durable_rename_excl() but leave the function around for any extensions that
are using it.  Of course, we'd also need a big comment imploring folks not
to add any more callers.  Another option would be to change the behavior of
durable_rename_excl() to something that we think is safer (e.g., stat then
rename), but that might just introduce a different set of problems.

[0] https://postgr.es/m/20220408194345.GA1541826%40nathanxps13

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

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()