> UNION will remove all duplicates, so that the result additionally requires to > be sorted. >Right, to avoid the SORT and UNIQUE - operation you can use UNION ALL by the way maybe apply hashing to calculate UNION be better ? ------------ pasman -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
