Re: [PERFORM] wal_level=archive gives better performance than minimal - why?

2012-02-04 Thread Tomas Vondra
On 4.2.2012 17:04, Cédric Villemain wrote: > Le 3 février 2012 19:48, Robert Haas a écrit : >> 2012/1/22 Tomas Vondra : >>> That's suspiciously similar to the checkpoint timeout (which was set to >>> 4 minutes), but why should this matter for minimal WAL level and not for >>> archive? >> >> I went

Re: [PERFORM] wal_level=archive gives better performance than minimal - why?

2012-02-04 Thread Cédric Villemain
Le 3 février 2012 19:48, Robert Haas a écrit : > 2012/1/22 Tomas Vondra : >> That's suspiciously similar to the checkpoint timeout (which was set to >> 4 minutes), but why should this matter for minimal WAL level and not for >> archive? > > I went through and looked at all the places where we invo

Re: [PERFORM] wal_level=archive gives better performance than minimal - why?

2012-02-03 Thread Robert Haas
2012/1/22 Tomas Vondra : > That's suspiciously similar to the checkpoint timeout (which was set to > 4 minutes), but why should this matter for minimal WAL level and not for > archive? I went through and looked at all the places where we invoke XLogIsNeeded(). When XLogIsNeeded(), we: 1. WAL log

Re: [PERFORM] wal_level=archive gives better performance than minimal - why?

2012-01-22 Thread Tomas Vondra
On 17.1.2012 01:29, Tomas Vondra wrote: > On 16.1.2012 23:35, Greg Smith wrote: >> On 01/12/2012 06:17 PM, Tomas Vondra wrote: >>> I've run a series fo pgbench benchmarks with the aim to see the effect >>> of moving the WAL logs to a separate drive, and one thing that really >>> surprised me is tha

Re: [PERFORM] wal_level=archive gives better performance than minimal - why?

2012-01-16 Thread Tomas Vondra
On 16.1.2012 23:35, Greg Smith wrote: > On 01/12/2012 06:17 PM, Tomas Vondra wrote: >> I've run a series fo pgbench benchmarks with the aim to see the effect >> of moving the WAL logs to a separate drive, and one thing that really >> surprised me is that the archive log level seems to give much bet

Re: [PERFORM] wal_level=archive gives better performance than minimal - why?

2012-01-16 Thread Greg Smith
On 01/12/2012 06:17 PM, Tomas Vondra wrote: I've run a series fo pgbench benchmarks with the aim to see the effect of moving the WAL logs to a separate drive, and one thing that really surprised me is that the archive log level seems to give much better performance than minimal log level. How r

[PERFORM] wal_level=archive gives better performance than minimal - why?

2012-01-12 Thread Tomas Vondra
Hi all, I've run a series fo pgbench benchmarks with the aim to see the effect of moving the WAL logs to a separate drive, and one thing that really surprised me is that the archive log level seems to give much better performance than minimal log level. On spinning drives this is not noticeable,