Tom Lane skrev: >> PG apparently is not smart enough to recognize that the >> result of a max must be one of the values of the column (meaning that it >> can use an index) > > That's because it can't. As written, the query demands sums over groups > that *include* a specific invoice_id --- but each sum has to include > contributions from rows that could have another invoice_id. So the > condition on invoice_id cannot be pushed down to the individual scans. > If, in fact, the correct answer could be had by fetching only rows with > the specified invoice_id, then you need to fix the view to make that > clear.
Well, the query can be satisfied by looking only at the rows with an order_id matching the invoice_id given. The condition that this is the largest invoice in the group then needs to be checked afterwards. I certainly did not expect the query planner to be able to deduce this, though. Nis ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
