Re: PostgreSQL as a local in-memory cache

Bruce Momjian <bruce@momjian.us> writes:
>>> I asked on IRC and was told it is true, and looking at the C code it
>>> looks true. ?What synchronous_commit = false does is to delay writing
>>> the wal buffers to disk and fsyncing them, not just fsync, which is
>>> where the commit loss due to db process crash comes from.

>> Ah, I see.  Thanks.

> I am personally surprised it was designed that way;  I thought we would
> just delay fsync.

That would require writing and syncing to be separable actions.  If
you're using O_SYNC or similar, they aren't.

            regards, tom lane