On Tuesday 12 February 2008 16:03:31 Glyn Astill wrote: > Thanks Mark, > > I've turned this on and I never see a DECLARE CURSOR so I presume I > was wrong and it is not using cursors. > > I do see a DEALLOCATE though, although no PREPARE. Before this it > does lots of statements that are limited to 100 records, and all the > statements are named and preceded by execute, so I presume it is > using prepared statements getting little chunks of data and relying > on the first execute to prepare them? Yup, it's using prepared queries. Unfortunately prepared queries are not always a good thing, because if your data is non-uniformly distributed then the planner has guess what will be the best plan without knowing what parameters you are passing in at run-time. Hence you may get a plan that is optimal for one set of values, but not for others. > Both tests were run over the network. Okay. From what you mention above, it's likely that what you're seeing is a bad query plan choice anyway. ATB, Mark. -- Mark Cave-Ayland Sirius Corporation - The Open Source Experts http://www.siriusit.co.uk T: +44 870 608 0063 ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
