Re: How to tell where to tune

andrew, are you using forced residency? you state the the bulk of the tbstat -FR is in chunk writes. this points to some tuning that can be done at the LRU level. it sounds like all of your LRU cleaning is being done at check points. lower your LRU parameters to (10,5) or even (5,2) - play around with this. also, take a look at the size of the process that is running. with 40MB of buffers, your shared memory segment is probably quit large and swapping of the application process could take time (renice -10 <pid> might help). you may want to lower you number of buffers incrementally while monitoring your cache percents - again, to decrease the overhead of the engine. lastly, take a look at your application. see if any tuning can be done to it. you say that you are converting data by sequentially reading a table and writing that data to many other tables. do the other tables have indexes (if so, can they be dropped and recreated after the conversion?). are you using prepared insert/update statements, etc. some of our biggest performance gains have come from 'tuning' applications. hope this helps. regards, ------------------------------------------------------------------------------ | . . Bob Baskett | ... ... Software Engineer, DBA | ..... ..... Business Systems Integration Group | .. ... .. Semiconductor Products Sector | . . . Mesa, AZ | | Motorola, Inc ------------------------------------------------------------------------------ Sun 690-MP Informix Versions: Online - 5.00.UC2 ISQL - 4.10.UD1 4GL-RDS- 4.10.UC1 ------------------------------------------------------------------------------