Richard Yen <dba@xxxxxxxxxxx> writes: > I've discovered a peculiarity with using btrim in an index and was > wondering if anyone has any input. What PG version is this? In particular, I'm wondering if it's one of the early 8.2.x releases, which had some bugs in and around choose_bitmap_and() that caused them to sometimes make weird choices of indexes in a BitmapAnd plan structure ... Like David, I'm pretty dubious that the behavior has anything to do with strings being 5 characters long exactly; but it could very much depend on whether the string you choose is a common last name or not. That would change the estimated number of matching rows and hence affect the apparent relative attractiveness of different indexes. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
