Horton

Re: EINTR in ftruncate()

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Andres Freund <andres@anarazel.de>
Cc: Thomas Munro <thomas.munro@gmail.com>, Pg Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-07-06T19:29:41Z
Lists: pgsql-hackers

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On 2022-Jul-05, Andres Freund wrote:

> I think we'd be better off disabling at least some signals during
> dsm_impl_posix_resize(). I'm afraid we'll otherwise just find another
> variation of these problems. I haven't checked the source of ftruncate, but
> what Thomas dug up for fallocate makes it pretty clear that our current
> approach of just retrying again and again isn't good enough. It's a bit more
> obvious that it's a problem for fallocate, but I don't think it's worth having
> different solutions for the two.

So what if we move the retry loop one level up?  As in the attached.
Here, if we get EINTR then we retry both syscalls.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"No hay hombre que no aspire a la plenitud, es decir,
la suma de experiencias de que un hombre es capaz"

Commits

  1. Provide sigaction() for Windows.

  2. Emulate sigprocmask(), not sigsetmask(), on Windows.

  3. Make dsm_impl_posix_resize more future-proof.

  4. Don't clobber postmaster sigmask in dsm_impl_resize.

  5. Create a distinct wait event for POSIX DSM allocation.

  6. Remove redundant ftruncate() for POSIX DSM memory.

  7. Block signals while allocating DSM memory.

  8. Remove dsm_resize() and dsm_remap().

  9. XLOG (also known as WAL -:)) Bootstrap/Startup/Shutdown.