Hi all, It occured to me on the plane home that now that CLUSTER is fixed we may be able to put pg_index.indisclustered to use. If CLUSTER was to set indisclustered to true when it clusters a heap according to the given index, we could speed up sequantial scans. There are two possible ways.
1) Planner determines that a seqscan is appropriate *and* the retrieval is qualified by the key(s) of one of the relation's indexes 2) Planner determines that the relation is clustered on disk according to the index over the key(s) used to qualify the retrieval 3) Planner sets an appropriate nodeTag for the retrieval (SeqScanCluster?) 4) ExecProcNode() calls some new scan routine, ExecSeqScanCluster() ? 5) ExecSeqScanCluster() calls ExecScan() with a new ExecScanAccessMtd (ie, different from SeqNext) called SeqClusterNext 6) SeqClusterNext() has all the heapgettup() logic with two exceptions: a) we find the first tuple more intelligently (instead of scanning from the first page) b) if we have found tuple(s) matching the ScanKey when we encounter an non-matching tuple (via HeapTupleSatisfies() ?) we return a NULL'ed out tuple, terminating the scan Any reason this isn't possible? Any reason it couldn't dramatically speed up the performance of the type of query i've mentioned? Gavin ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org