Re: High load on commit after important schema changes

On Fri, Aug 28, 2009 at 12:47:15PM -0400, Tom Lane wrote:
> hubert depesz lubaczewski <depesz(at)depesz(dot)com> writes:
> > On Fri, Aug 28, 2009 at 12:28:06PM -0400, Tom Lane wrote:
> >> Hm, do you have forty or so idle backends hanging around while this
> >> happens? The only thing I can think of that might be causing this is
> >> shared cache invalidation messages being broadcast to all the other
> >> sessions.
> > I have about 1000 backends running.
> Ouch. You need to update to 8.4 --- the SI messaging stuff will
> definitely be hurting you with that many backends. Or consider
> using connection pooling or something to cut the number of backends.

Do you have any idea on how (easily) to test if this is the cause of the
situation?

Will running 1000 connections to db, making each of them run query on
some table, keep the connection open, and then in another connection
doing the rename thing on it - work?

Best regards,

depesz

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