Horton
Menu

Re: BUG #18146: Rows reappearing in Tables after Auto-Vacuum Failure in PostgreSQL on Windows

Thomas Munro <thomas.munro@gmail.com>

View thread
From: Thomas Munro <thomas.munro@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Paquier <michael@paquier.xyz>, Laurenz Albe <laurenz.albe@cybertec.at>, rootcause000@gmail.com, pgsql-bugs@lists.postgresql.org
Date: 2023-10-04T22:38:24Z
Lists: pgsql-bugs 
On Thu, Oct 5, 2023 at 10:12 AM Thomas Munro <thomas.munro@gmail.com> wrote:
> It's surprising that ftruncate() AKA chsize() is able to fail like
> this (I am not a Windows user but AFAIR that sharing stuff obstructs
> stuff like open, unlink, rename, so it surprises me to see it come up
> with ftruncate, since we must already have made it past the open
> stage).  Hmm, the documentation is scant, but I know from my attempts
> to use large files that chsize() is probably some kind of wrapper
> around SetEndOfFile() or similar, and that is documented as failing if
> someone has the file mapped.  I don't know why someone would have the
> file mapped, though.

Some more thoughts: I guess it would probably also fail like that if
someone explicitly locked a range with LockFile(), but I think we can
rule that out as read and/or write calls would also fail.  As for the
mapping theory, apparently the underlying NT error for that is
ERROR_USER_MAPPED_FILE, and searching for that brings up various
unexplained errors vaguely blamed on anti-virus tools etc.  But if all
of that sort of thing really is turned off for the data directory, I
wonder if there could be a backup tool in use that thinks it can go
faster by mapping files while copying?

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix C error reported by Oracle compiler.

  2. Restore smgrtruncate() prototype in back-branches.

  3. Fix corruption when relation truncation fails.

  4. RelationTruncate() must set DELAY_CHKPT_START.

  5. WAL-log inplace update before revealing it to other sessions.

  6. Fix bugs in MultiXact truncation

  7. Fix possible recovery trouble if TRUNCATE overlaps a checkpoint.