On 27 Srpen 2011, 6:01, Noah Misch wrote: > On Fri, Aug 26, 2011 at 10:46:33AM +0200, Tomas Vondra wrote: >> 1. collect pg_stat_bgwriter stats >> 2. run pgbench for 10 minutes >> 3. collect pg_stat_bgwriter stats (to compute difference with (1)) >> 4. kill the postmaster >> >> The problem is that when checkpoint stats are collected, there might be >> a >> checkpoint in progress and in that case the stats are incomplete. In >> some >> cases (especially with very small db blocks) this has significant impact >> because the checkpoints are less frequent. > > Could you remove this hazard by adding a step "2a. psql -c CHECKPOINT"?
I already do that, but it really does not solve the issue. It just aligns the first expected 'timed' checkpoint, it does not solve the problem with in-progress checkpoints unless the runs behave exactly the same (and that's the boring case). Tomas -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
