--- Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> <ogjunk-pgjedan(at)yahoo(dot)com> writes:
> > VACUUMing this DB takes about 30 minutes, and during that time the
> > is pretty unresponsive, although the PG process is not using a lot
> > CPU (load ~ 1) nor memory (~20MB for the VACUUM process).
> How big is the DB physically ("du $PGDATA" results)?
# du -h ~postgres/data
> If you've been lax
> about vacuuming or not had your FSM parameters set high enough, there
> could be a whole lot of dead space for VACUUM to scan through.
I've been vacuuming every night, like a good DBwife.
> If so,
> VACUUM FULL or possibly CLUSTER would be the best way to re-compact
> tables. (VACUUM VERBOSE on your larger tables would be another way
> investigate this.)
I will try VACUUM VERBOSE on the biggest (and most active) table
tonight and report the findings.
> The other possibility is that you have a seriously slow disk drive
It looks like I have an ATA-6 drive with only 2MB cache, and the
# /sbin/hdparm -tT /dev/hda
Timing buffer-cache reads: 128 MB in 0.56 seconds =228.57 MB/sec
Timing buffered disk reads: 64 MB in 1.18 seconds = 54.24 MB/sec
Not SCSI, not RAID, but not the slowest HDD on the continent.
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