Hi, I actually have several questions on indexes and operator classes:
1) What is the difference between *varchar_pattern_ops* and * varchar_text_ops*? They both appear to work similarly and in both cases the operands are cast to type TEXT when I look at the explain of the query. 2) Is there any pre-definded operator class for indexes with regular expressions? 3) How do I define an index which would be invoked when querying with regexps in the WHERE-clause? 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. Oracle 11 apparently has no pre-defined operator classes (they call them "application domain indexes") and only includes a documentation on how to make them which is more or less around three corners and climbing stairs while balancing a water cup on your nose - this appears to me to be a very big marketing advantage for Postgres over Oracle. Should I post a bug report to the PGSQL-BUGS list against the documentation ? Thanks, R.
