Re: text_pattern_ops and complex regexps

On Wed, May 06, 2009 at 12:10:49PM -0400, Alvaro Herrera wrote:
> Tom Lane wrote:
> > Stephen Frost <sfrost(at)snowman(dot)net> writes:
>
> > > Perhaps this is misguided but I would think that the regexp
> > > libraries might have some support for "give me all anchored
> > > required text for this regexp" which we could then use in the
> > > planner.
> >
> > I wouldn't see why. It's certainly worth considering to hand the
> > pattern to the regex engine and then burrow into the data
> > structure it builds; but right now we consider that structure to
> > be entirely private to backend/regex/. There's also the problem
> > that we'd have no easy way to determine how much the result
> > depends on the current regex flavor setting. There are some cases
> > now where regex_fixed_prefix deliberately omits possible
> > optimizations because of uncertainty about the flavor.
>
> I think changeable regex flavors turned out to be a bad idea.

+1

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
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