Reid Thompson <Reid.Thompson@xxxxxxxx> writes: > What am I missing that causes this to resort to sorting on disk? The in-memory space required to sort N tuples can be significantly larger than the on-disk space, because the latter representation is optimized to be small and the in-memory representation not so much. I haven't seen a 3X differential before, but it's not outside the realm of reason, especially for narrow rows like these where it's all about the overhead. I suspect if you crank work_mem up still more, you'll see it switch over. It flips to on-disk sort when the in-memory representation exceeds the limit ... 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
