Re: Postgres, fsync, and OSs (specifically linux)

On 18 May 2018 at 00:44, Andres Freund <andres(at)anarazel(dot)de> wrote:

> Hi,
>
> On 2018-05-10 09:50:03 +0800, Craig Ringer wrote:
> > while ((src = (RewriteMappingFile *) hash_seq_search(&seq_status))
> != NULL)
> > {
> > if (FileSync(src->vfd, WAIT_EVENT_LOGICAL_REWRITE_SYNC)
> != 0)
> > - ereport(ERROR,
> > + ereport(PANIC,
> > (errcode_for_file_access(),
> > errmsg("could not fsync file
> \"%s\": %m", src->path)));
>
> To me this (and the other callers) doesn't quite look right. First, I
> think we should probably be a bit more restrictive about when PANIC
> out. It seems like we should PANIC on ENOSPC and EIO, but possibly not
> others. Secondly, I think we should centralize the error handling. It
> seems likely that we'll acrue some platform specific workarounds, and I
> don't want to copy that knowledge everywhere.
>
> Also, don't we need the same on close()?
>
>
Yes, we do, and that expands the scope a bit.

I agree with Robert that some sort of filter/macro is wise, though naming
it clearly will be tricky.

I'll have a look.

--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services