ERR ORR <rd0002@xxxxxxxxx> writes: > 1) What is the difference between *varchar_pattern_ops* and * > varchar_text_ops*? None whatsoever --- they're both there just so that people can write an opclass name that matches the declared type of their table column. > 2) Is there any pre-definded operator class for indexes with regular > expressions? No, not yet. > 3) How do I define an index which would be invoked when querying with > regexps in the WHERE-clause? You don't. Alexander Korotkov is hacking on an extension to contrib/pg_trgm that would allow probing a GIN index with trigrams extracted from a regexp, but it's a hard problem --- he's been working on that for many months and it's still not committed. > 4) There appears to be no documentation of the included operator classes in > the > Postgresql documentation while the feature looks to me like its use cannot > be > emphasized enough. > Postgresql 9.1.7 has about 220 operator classes but very few of them are > even > mentioned in the manual. Most of them don't need to be, because they're the default (and usually only) opclass for their datatype+index type anyway. The ones that are non-default are documented in appropriate places. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
