Guillaume Cottenceau <gc@mnc.ch> writes:
> I have made a comparison restoring a production dump with default
> and large maintenance_work_mem. The speedup improvement here is
> only of 5% (12'30 => 11'50).
> Apprently, on the restored database, data is 1337 MB[1] and
> indexes 644 MB[2][2]. Pg is 8.2.3, checkpoint_segments 3,
> maintenance_work_mem default (16MB) then 512MB, shared_buffers
> 384MB. It is rather slow disks (Dell's LSI Logic RAID1), hdparm
> reports 82 MB/sec for reads.
The main thing that jumps out at me is that boosting checkpoint_segments
would probably help. I tend to set it to 30 or so (note that this
corresponds to about 1GB taken up by pg_xlog).
regards, tom lane