Re: Vacuum wait time problem

On Freitag 13 Februar 2009 Roger Ging wrote:
> I'm running vacuum full analyze verbose on a table with 20million
> rows and 11 indexes.  In top, I'm seeing [pdflush] and postgres:
> writer process each using diferent cpu cores, with wait time well
> above 90% on each of them.  The vacuum has been running for several
> hours

Roger, I've had the same issue some time ago and wondered why it was so
slow. I did "iostat -kx 5 555" and saw that I/O was also quite low.

vacuum_cost_delay = 0
That was the trick for me. It was set to 250(ms), where it took 5 hours
for a vacuum to run. Now it takes 5-15 minutes.

And for your bloated table, you should also REINDEX afterwards, because
likely the index will be a mess also.

mfg zmi
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