Tom Lane kirjutas K, 05.02.2003 kell 01:35: > Neil Conway <[EMAIL PROTECTED]> writes: > > Speaking of which, is there (or should there be) some mechanism for > > increasing the size of the compiled pattern cache? Perhaps a GUC var? > > I thought about that while I was messing with the code, but I don't > think there's much point in it, unless someone wants to invest the work > to make the cache search much smarter (maybe a hash table?). At present > a larger cache will cost you in extra search time, especially in the > case where the pattern isn't in the cache. > > I did do the work last night to convert the cache management algorithm > into a self-organizing list (a la Knuth) rather than a round-robin > search as it was before. This should reduce the expected number of > comparisons for cases where the cache is actually accomplishing > something, but of course it's no help if you have too many patterns > for the cache.
Perhaps the decision weather to try to use the cache at all could be done at planning time depending on statistics information ? Another idea is to make special regex type and store the regexes pre-parsed (i.e. in some fast-load form) ? -- Hannu Krosing <[EMAIL PROTECTED]> ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
