Re: Speeding up LIKE with placeholders? - Mailing list pgsql-general

From Tom Lane
Subject Re: Speeding up LIKE with placeholders?
Date
Msg-id 2939.1094851162@sss.pgh.pa.us
Whole thread Raw
In response to Speeding up LIKE with placeholders?  (Dan Sugalski <dan@sidhe.org>)
Responses Re: Speeding up LIKE with placeholders?  (Dan Sugalski <dan@sidhe.org>)
List pgsql-general
Dan Sugalski <dan@sidhe.org> writes:
> I'd figure, though, that since the parameters are being passed
> into PQexecParams basically to get them out of band so I don't have
> to deal with escaping, quoting, and suchlike things, that the
> optimizer would look at things *after* the substitution was done.

You'd figure wrong :-(.  The present mechanism for the LIKE-to-index
optimization requires the LIKE pattern to be a pure, unadulterated constant.

            regards, tom lane

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