On 4/2/13 10:26 AM, Tom Lane wrote: > The issue with the LIKE special case is that left-anchored patterns > are (to some extent) indexable with ordinary btree indexes, and so we > want to exploit that rather than tell people they have to have a whole > other index.
In practice, you need an index specifically for pattern matching anyway. The difference would be that instead of using a different operator class that has no recorded association with the original operator, you'd use a different access method that is associated with the operator in normal ways. > So it's a pretty special case, but there are just enough instances of it > to wish for some not-so-hard-wired way to deal with it. Are there any widely known non-built-in cases besides citext? Presumably the reason you use citext is that you use a lot of letters. So I kind of doubt that there are going to be a lot of cases of pattern searches on citext with left-anchored patterns starting with (a sufficient number of) non-letters. It's possible, of course, but doesn't seem important enough by itself. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
