Re: Notes about fixing regexes and UTF-8 (yet again)

Tom Lane <tgl@sss.pgh.pa.us> writes:
> Yeah, it's conceivable that we could implement something whereby
> characters with codes above some cutoff point are handled via runtime
> calls to iswalpha() and friends, rather than being included in the
> statically-constructed DFA maps.  The cutoff point could likely be a lot
> less than U+FFFF, too, thereby saving storage and map build time all
> round.

It's been proposed to build a “regexp” type in PostgreSQL which would
store the DFA directly and provides some way to run that DFA out of its
“storage” without recompiling.

Would such a mechanism be useful here?  Would it be useful only when
storing the regexp in a column somewhere then applying it in the query
from there (so most probably adding a join or subquery somewhere)?

Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support