Edmund Dengler <edmundd@eSentire.com> writes: > Hmm, interesting as I have that table clustered starting with the > rep_component, so 'ps_probe' will definitely appear later in a sequential > scan. So why does the <order by> force the use of the index? It does not "force" anything, it simply alters the cost estimates. The seqscan-based plan requires an extra sort step to meet the ORDER BY, while the indexscan plan does not. In this particular scenario the indexscan plan is estimated to beat seqscan+sort, but in other cases the opposite decision might be made. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
