Re: Async Commit, v21 (now: v22)

Tom Lane wrote:
> Gregory Stark <stark@enterprisedb.com> writes:
>> Without async commits? Do we really want the walwriter doing the
>> majority of the wal-flushing work for normal commits? It seems like
>> that's not going to be any advantage over just having some random
>> backend do the commit.
>
> Sure: the advantage is that the backends (ie, user query processing)
> don't get blocked on fsync's.  This is not really different from the
> rationale for having the bgwriter.  It's probably most useful for large
> transactions, which up to now generally had to stop and flush the WAL
> buffers every few pages worth of WAL output.

I wonder what it would take to offload the CRC calculation to the wal
writer. And if that would then become a bottleneck, making it actually
counterproductive.

No, not in this release :).

--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com