Re: How to enhance the chance that data is in disk cache

Jona <jonanews@oismail.com> writes:
> I have a query (please refer to
> http://213.173.234.215:8080/get_content_plan.htm for the query as well
> as query plan) that is slow when it's run the first time and fast(ish)
> on all successive runs within a reasonable time period.

> This leads me to suspect that when the query is first run, all used data
> have to be fetched from the disk where as once it has been run all data
> is available in the OS's disk cache.

Sounds like that to me too.

> Is there anway to either enhance the chance that the data can be found
> in the disk cache or allowing the database to fetch the data faster?

Run the query more often?

Also, that pile of INNER JOINs is forcing a probably-bad join order;
you need to think carefully about the order you want things joined in,
or else convert the query to non-JOIN syntax.  See the "Performance
Tips" chapter of the manual.

            regards, tom lane