Horton

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

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Craig Ringer <craig@2ndquadrant.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Simon Riggs <simon@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2018-05-17T16:44:41Z
Lists: pgsql-hackers 
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()?

- Andres

Commits

  1. PANIC on fsync() failure.

  2. Fix and improve pg_atomic_flag fallback implementation.