> Well, all the textual operators/functions are actually
> declared to take
> and return type TEXT, so when you are working with VARCHAR
> columns the
> expressions have no-op cast nodes in them ("RelabelType"
> nodes), even
> if it's an unconstrained-length VARCHAR. I'm not sure whether
> the
> execution cost of these would be measurable in real
> applications, but
> it's not zero. A bigger problem is that sometimes the planner
> gets
> confused by the RelabelTypes and fails to find as good a plan
> as it
> finds for a pure-TEXT query.
I assume this is true for version 7 as well as version 8.
Bruce
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