Allen Landsidel <alandsidel@xxxxxxxxx> writes: > With that many rows, and a normal index on the field, postgres figures > the best option for say "I%" is not an index scan, but a sequential > scan on the table, with a filter -- quite obviously this is slow as > heck, and yes, I've run analyze several times and in fact have the > vacuum analyze automated. > With the partial index the index scan is used and the cost drops from > 0..2million to 0..9000 -- a vast improvement. Hmm. This suggests to me that you're using a non-C locale and so a plain index *can't* be used for a LIKE query. Can you force it to use an indexscan by setting enable_seqscan = false? If not then you've got a locale problem. As someone else pointed out, this can be worked around by creating an index with the right operator class. regards, tom lane
