Thomas Samson wrote: > On 8/22/06, Alvaro Herrera <alvherre@xxxxxxxxxxxxxxxxx> wrote: > >Ulrich Habel wrote: > >> Hello all, > >> had an idea of optimizing a query that may work generally. > >> > >> In case a 'column' is indexed, following two alterations could be done > >> I think: > >> > >> A) > >> > >> select ... where column ~ '^Foo' --> Seq Scan > > > >This is not true. You can make this query use an index if you create it > >with opclass varchar_pattern_ops or text_pattern_ops, as appropiate. > > > >Thus you don't need any hack here. > > > > And in the case of more general expression, like: > select ... where column ~ 'something'; > > Is there a way to optimise this ? (in the case where 'something' is not > a word, but a part of a word) Not sure. I'd try tsearch2 or pg_trgm (or pg_tgrm, whatever it's called). It's trigram indexing. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support
