Tom Lane wrote:
Heikki Linnakangas <heikki.linnakan...@enterprisedb.com> writes:
I was going to say that since we flush the WAL every 16MB anyway (at
every XLOG file switch), you shouldn't see any benefit with larger ring
buffers, since to fill 16MB of data you're not going to write more than
16MB WAL.
I'm not convinced that WAL segment boundaries are particularly relevant
to this. The unit of flushing is an 8K page, not a segment.
We fsync() the old WAL segment every time we switch to a new WAL
segment. That's what I meant by "flush".
If the walwriter is keeping up, it will fsync() the WAL more often, but
16MB is the maximum distance between fsync()s.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
