Re: autovacuum: 50% iowait for hours

On Thu, May 13, 2010 at 7:05 PM, Joao Ferreira
<joao(dot)miguel(dot)c(dot)ferreira(at)gmail(dot)com> wrote:
>
> Hello all,
>
> I have a hard situation in hands. my autovacuum does not seem to be able
> to get his job done;
>
> database is under active INSERTs/UPDATEs;
> CPU is in aprox 50% iowait for the past 5 hours;
>

vmstat divides io percent (last column) per cpu core. Probabily you
have 100%, look iostat last column (util).

> I've tried turning off autovacuum and the effect goes away; I turn it back
> on and it goes back to 50% iowait; my IO system is nothing special at all;
>
> besides turning autovacuum off and running vacuum by hand once in a while,
> what else can I do to get out of this situation ?
>
> bellow some logs
>
> I'm seriously considering turning off autovacuum for good; but I'dd like
> to get input concerning other approaches... I mean... if I don't turn it
> of, how can I be sure this will not happen again... we ship products with
> PG inside... I must be absolutelly sure this will not ever happen in any of
> our costumers. I'm a bit confuse... sorry :) !
>
> Joao
>

schedule the vacum to midnight

--
Reinaldo de Carvalho
http://korreio.sf.net
http://python-cyrus.sf.net