Ben <bench@xxxxxxxxxxxxxxx> writes: > Wouldn't it need to check the unique constraint (an index on the table) > before the insert can succeed? It seems like it would be better to check > the index than to do a full table scan to try to satisfy that constraint. Postgres contains no code that would even consider doing a seqscan for a uniqueness check; it could not work because of race-condition considerations, never mind performance. You have not given us any clue about where the seqscans are really coming from ... have you got any user-defined triggers, SQL functions in CHECK constraints, stuff like that? regards, tom lane
