Why should these queries have different plans? create table foo (a int PRIMARY KEY); Q1: explain select max(a) from foo > Result (cost=0.04..0.05 rows=1 width=0) > InitPlan > -> Limit (cost=0.00..0.04 rows=1 width=4) > -> Index Scan Backward using foo_pkey on foo > (cost=0.00..76.10 rows=2140 width=4) > Filter: (a IS NOT NULL) Q2: explain select max(a) from (select * from foo) as f > Aggregate (cost=36.75..36.76 rows=1 width=4) > -> Seq Scan on foo (cost=0.00..31.40 rows=2140 width=4) I need the lovely index scan, but my table is hidden behind a view, and all I get is the ugly sequential scan. Any ideas on how to convince the optimizer to unfold the subquery properly? Bill
