Re: Performance Tuning Question

On Mon, Sep 09, 2002 at 09:41:30AM -0600, Brian Hirt wrote:
>
> I know this, but i cannot find any good reference how to tune them and
> how changing them.

[. . .]

> FYI: I did set effective_cache_size to 1.5gb, but the estimated cost for
> the query using the index remained exactly the same.

You probably want to twiddle CPU_INDEX_TUPLE_COST (floating point)
and RANDOM_PAGE_COST (floating point). But note what the docs say
about these items:

Note: Unfortunately, there is no well-defined method of determining
ideal values for the family of "COST" variables that were just
described. You are encouraged to experiment and share your findings.

If you have any luck, it'd be nice to know what you discover.

A

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