I was able to duplicate this behavior with dummy data that had only a few distinct values for fknamestringid --- the planner then thinks that the index probe into attribute will match a lot of rows and hence take a long time. Could we see your pg_stats row for fknamestringid, ie
select * from pg_stats where tablename = 'attribute' and attname = 'fknamestringid'; It would be interesting to see the same for your 7.4 installation too. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings