Re: Tuning Online ?

Christoph Adomeit (ado@ibg1.gtn.com) wrote: : Hi there, : maybe there is someone out here who has an idea what can be tuned here. : It's a Sco-Unix 486/50 Machine with 64 MB of RAM. It's a dedicated : database server and serves for about 30 Users, but they use it heavily in : a large business Application. : From my point of view it's unbelieveable fast, but the customer would like : it to be faster in some special selects, but these selects are complicated : and absolutely optimized using indices and no temporary files:-(. What do you mean by "absolutely optimized ..... no temporary files"? I've foundthat the ultimate optimization on some problem queries often requires the creation of some temporary files to nudge the optimizer into doing its thing correctly. Why don't you post your worst query, along with related table and index info, along with the output of "set explain on"? I'm sure that some of the resident gurus here can give you an idea as to possible improvements. Be sure and include info about number of rows in the tables. : How large would be the effect of unloading the database and recreating it : with optimized extent sizes ? Some tables meanwhile have more than 30 : extents ? What does tbcheck -pe tell you? How badly are your tables fragmented? As a general rule, you need to keep the total extents under 8. : Would it make sense to install 1 more SCSI Hard-Disk for the DBTEMP : Directory and the Informix stuff ? In the Moment thats on the same drive as : the database. What's your existing disk setup? Try running tbstat -D repeatedly while the database is in operation. Where are your writes and reads occurring? : Some info from tbstat: params deleted -- =========================================================================== jlumbley@netcom.com (Joe Lumbley) "If you believe that my statements Database Administrator represent my company, please send The Tigon Corporation money and I'll send you stock" Dallas, Texas Watch for my _INFORMIX DBA SURVIVAL GUIDE_ in Fall '94 from Prentice Hall! ===========================================================================