Re: Very big insert/join performance problem (bacula)

Marc Cousin <cousinmarc@gmail.com> wrote:

> As mentionned in another mail from the thread (from Richard Huxton),
> I felt this message in the documentation a bit misleading :
>
> effective_cache_size (integer)
>  Sets the planner's assumption about the effective size of the disk
>  cache that is available to a single query
>
> I don't really know what the 'a single query' means. I interpreted
> that as 'divide it by the amount of queries typically running in
> parallel on the database'. Maybe it should be rephrased ? (I may not
> be the one misunderstanding it).

I'm afraid I'll have to let someone else speak to that; I only have a
vague sense of its impact.  I've generally gotten good results setting
that to the available cache space on the machine.  If I'm running
multiple database clusters on one machine, I tend to hedge a little
and set it lower to allow for some competition.

-Kevin