Tom Lane wrote: > Stephen Frost <sfr...@snowman.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. They can wreak all sorts of havoc. You change the setting, SIGHUP, and suddenly your application fails to work as expected. Maybe we should make that setting PGC_POSTMASTER (or just get rid of it?), and provide was to pass flags to change the flavor for particular operations (this is easy for function-based stuff but not so easy for operators). That way it doesn't intrude in stuff like cached plans and so on. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers