Does iscachable work?
Hello,
I'm running PostgreSQL 7.1.3, and I have a query that uses one of my
functions:
select findregion(entityid) from msg200;
The findregion function is set to be 'with (iscachable)'. However, the
query takes upwards of 40 seconds to run, consistently. The table only
has 20000 rows or so. It doesn't seem like the caching is working.
The only other time I tried to use function results caching, it actually
consistently increased my execution time. Anything I need to be doing
differently?
Thanks,
Fran
If "entityid" has a lot of unique values, you won't
get much gain from caching. My experience is that the
gain can be stunning in cases where there are few
distinct values in a column. The best way to know the
benefit in a given case is to test it.
If your function is highly computation-intensive, or
(for example) makes selects against the database that
require full table scans, then you will see slow
results no matter what.
--- root <ffabrizio@exchange.webmd.net> wrote:Hello,
I'm running PostgreSQL 7.1.3, and I have a query
that uses one of my
functions:select findregion(entityid) from msg200;
The findregion function is set to be 'with
(iscachable)'. However, the
query takes upwards of 40 seconds to run,
consistently. The table only
has 20000 rows or so. It doesn't seem like the
caching is working.The only other time I tried to use function results
caching, it actually
consistently increased my execution time. Anything
I need to be doing
differently?Thanks,
Fran---------------------------(end of
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