Re: Help with function optimisation - Mailing list pgsql-sql

From Tom Lane
Subject Re: Help with function optimisation
Date
Msg-id 16607.1026308076@sss.pgh.pa.us
Whole thread Raw
In response to Help with function optimisation  ("Ian Cass" <ian.cass@mblox.com>)
List pgsql-sql
"Ian Cass" <ian.cass@mblox.com> writes:
> I've got a function that I run as a trigger to update a summary table on
> insert to the main table. As you can see below, it does a select & an INSERT
> if not found, or an UPDATE if found. This currently works OK, but I'd like
> to improve performance by removing the SELECT & attempting an UPDATE. If it
> fails, I'd like to INSERT instead. Can this be done?

Sure.  Do the UPDATE, check how many rows updated; if none, INSERT.

Finding out how many rows were updated involves a plpgsql command
"GET DIAGNOSTICS varname = ROW_COUNT" (gotta love these Oracle-derived
syntaxes :-()
        regards, tom lane


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