Re: [HACKERS] TODO item: Implement Boyer-Moore searching (First time hacker)
Heikki Linnakangas <[email protected]> Fri, 05 Sep 2008 20:25:56 +0300
| Newsgroups | gmane.comp.db.postgresql.devel.patches |
|---|---|
| Organization | EnterpriseDB |
| Message-ID | <[email protected]> |
Tom Lane wrote: > "David Rowley" <[email protected]> writes: >> Tom Lane wrote: >>> Hmm. B-M-H has worst case search speed O(M*N) (where M = length of >>> pattern, N = length of search string); whereas full B-M is O(N). Maybe we >>> should build the second table when M is large? > >> I'll look into this. If it pays off for longer searches I'll submit a patch. >> I won't have the time until after the 15th, so perhaps that's in November's >> commit fest? > > Yes. Let's get B-M-H in during this fest and then you can look into > whether a follow-on patch is worthwhile. Agreed. Also, it would be nice to use B-M(-H) for LIKE as well. That's a different codepath, but probably more widely used than textpos and frients. I haven't looked how feasible it would be to do, though. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-patches mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-patches