On Tue, Oct 26, 2010 at 10:13 AM, Rob Wultsch <wultsch@xxxxxxxxx> wrote: > The double write buffer is one of the few areas where InnoDB does more > IO (in the form of fsynch's) than PG. InnoDB also has fuzzy > checkpoints (which help to keep dirty pages in memory longer), > buffering of writing out changes to secondary indexes, and recently > tunable page level compression. Baron Schwartz was talking to me about this at Surge. I don't really understand how the fuzzy checkpoint stuff works, and I haven't been able to find a good description of it anywhere. How does it keep dirty pages in memory longer? Details on the other things you mention would be interesting to hear, too. > Given that InnoDB is not shipping its logs across the wire, I don't > think many users would really care if it used the double writer or > full page writes approach to the redo log (other than the fact that > the log files would be bigger). PG on the other hand *is* pushing its > logs over the wire... So how is InnoDB doing replication? Is there a second log just for that? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
