jonathan vanasco <postgres@xxxxxxxx> writes: > What I noticed when checking stats earlier, is that although `idx_test_foo_id_asc` is the same as the PKEY... it was used about 10x more than the pkey. > Does anyone know of this is just random (perhaps due to the name being sorted earlier) or there is some other reason that index would be selected ? It's almost certainly just an artifact. The planner considers a table's indexes in OID order. I don't recall offhand whether it would keep the first or last of a series of identical-cost plans, but it'd be one or the other of those behaviors; it would not continue to consider both indexes once it noticed the plans were the same. One thing that could favor a newer index is that it probably has somewhat less bloat in it, resulting in a fractionally smaller cost estimate. This doesn't make it better in any absolute sense; reindexing the older index would reverse that preference, at least for a time. 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
