>> SELECT dokumnr FROM rid WHERE dokumnr NOT IN >> (select dokumnr FROM dok); > ... >> Is it possible to speed up this query is Postgres ? How to force Postgres >> to use indexes for this query ? > > Use IN and NOT IN only for small sets. Use JOIN (instead of IN) and LEFT > JOIN (instead of NOT IN) for larger sets. e.g.: > > SELECT rid.dokumnr > FROM rid > LEFT JOIN dok ON (dok.dokumnr = rid.dokumnr) > WHERE dok.dokumnr iS NULL;
Thank you. How to use this technique to speed up the update statement UPDATE rid SET dokumnr=NULL WHERE dokumnr NOT IN (SELECT dokumnr FROM dok); and DELETE statement DELETE FROM rid WHERE dokumnr NOT IN (SELECT dokumnr FROM dok); Andrus ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
