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 robertmh...@gmail.com a écrit : 2012/1/22 Tomas Vondra t...@fuzzy.cz: 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

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 robertmh...@gmail.com a écrit : 2012/1/22 Tomas Vondra t...@fuzzy.cz: 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

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

2012-02-03 Thread Robert Haas
2012/1/22 Tomas Vondra t...@fuzzy.cz: 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:

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 that the

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

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 better