Hi, Is there any "rule of thumb" on when to (not) use clustered indexes? What appen to the table/index? (any change on the physical organisation?) I've seen speed improvement on some queries but I'm not sure if I must use them or not... My rows are imported in batch of 100 (once the main script has collected them, this takes between 1 and 30min), then another script vacuums the table and aggregate the last imported rows, if I add a column with the commit timestamp and cluster on it, will I gain some perfs or not? Thanks, -- MaXX ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq