"Tom Lane" <[EMAIL PROTECTED]> writes: > "Gregor Roessle" <[EMAIL PROTECTED]> writes: >> The Server hangs when executing a query like this: > >> select * from messwerte where pknr = 28315178 and isproducing = 't' order by >> timestamp desc limit 1; > > I seriously doubt that it's hung. Takes a long time, maybe so. Is it > trying to use an indexscan on timestamp to substitute for a sort step?
Surely it wouldn't make 32ms become long enough to qualify as "hung". Unless perhaps it's otherwise using an index on pknr and/or isproducing and with the "ORDER BY timestamp desc LIMIT 1" it's using a different large index. I think we have to see EXPLAIN ANALYZE select * from messwerte where pknr = 28315178 and isproducing = 't' order by timestamp; EXPLAIN ANALYZE select * from messwerte where pknr = 28315178 and isproducing = 't' limit 1; EXPLAIN select * from messwerte where pknr = 28315178 and isproducing = 't' order by timestamp limit 1; -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's On-Demand Production Tuning ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
