Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1? - Mailing list pgsql-performance

Andres Freund <andres@anarazel.de> writes:
> On Wednesday 17 November 2010 01:51:28 Tom Lane wrote:
>> Well, there's a forced fsync after writing the last page of an xlog
>> file, but I don't believe that proves that more than 16MB of xlog
>> buffers is useless.  Other processes could still be busy filling the
>> buffers.

> Maybe I am missing something, but I think the relevant AdvanceXLInsertBuffer()
> is currently called with WALInsertLock held?

The fsync is associated with the write, which is not done with insert
lock held.  We're not quite that dumb.

            regards, tom lane