The query is technically on one table. It uses a join as a filter only. The table is 5.1 million rows (~3.4G) and stays relatively constant. SELECT t_00.uname, t_00.erdat, t_00.aezeit, t_00.kpackey, t_00.trantype, t_00.lmnga FROM sapr3.zkpacdata t_00, sapr3.zkpacreasoncodes t_01 WHERE (t_00.reasoncode = t_01.reasoncode(+) AND t_00.werks = t_01.werks(+)) AND t_00.mandt = '010' AND t_00.loekz <> 'X' AND t_00.vornr = '6100' AND t_00.aufnr = '000012284021' AND t_00.werks = 'MS' This query took 4.5 hours. When I run an explain plan the cost is 1. That's why I'm confused. My initial thought was that there was something locking the table but even that wouldn't necessarily explain the 4.5 hours. The program was run again during a maintenance window and it still took 6 hours. William ________________________________ From: jack.van.zanen@xxxxxxxxx [mailto:jack.van.zanen@xxxxxxxxx] On Behalf Of Jack van Zanen Sent: Thursday, December 11, 2008 10:17 PM To: Blanchard William Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: 10g slowdown are you saying that a query on a single table takes 6 hours? How big is the table in GB/TB? Jack 2008/12/12 Blanchard William <William.Blanchard@xxxxxxxxxx> We have a query that began taking a long time about a week ago. The program, in SAP, ran for 10 - 15 minutes but is now taking about 6 hours. The table has 5.1 million rows. The explain plan shows a simple index range scan. We just reran statistics on the table and all indexes but no luck We are concentrating on the one query that took about 4.75 hours. Does anyone see something glaring or know of a simple test to locate the problem? Let me know if you need any other info. Thank you, William B. -- J.A. van Zanen