Re: stats/checks in 24X7 environment ?

Thank you all for the input. ----- Original Message ---- From: Art S. Kagel <kagel@bloomberg.net> To: informix-list@iiug.org Sent: Tuesday, December 12, 2006 7:05:50 PM Subject: Re: stats/checks in 24X7 environment ? david@smooth1.co.uk wrote: > Art S. Kagel wrote: > >>infx dba wrote: >> >>>Hi, >>> >>>Need to know when you'll run stats and onchecks in a 24X7 environment, >>>in the organization where i am working we alternate stats and checks >>>every sunday, during this time we also have users connecting to the >>>database and run jobs. replication is not an option for us, need to know >>>when you'll run stats and checks in the 24X7 environment ? >> > > We do not have a full 24x7 operation we have a weekly maintanence > window. > > Why can you not have a maintence window at the weekend? > > onchecks can be run against a copy restored onto another machine. > > Normally update stats have to be run on the original machine. > I doubt you can sucessfully copy the results from update stats from a > copy. I related this one before: Actually, you CAN! I have it from one of the original optimizer guys that sysdistrib is the only source of distribution information and is treated as an ordinary SQL table (which it is). So you can DELETE FROM SYSDISTRIB; followed by LOAD FROM distributions.file INSERT INTO SYSDISTRIB; It's safe. Did it once from one sister server to another that was not replicated because the stats worked fine on one server but no matter what options we passed to UPDATE STATISTICS on the other machine the queries were using inefficient query paths. Deleting all the distributions from the 'bad' server and imposing the working distributions from the 'good' one solved the problem. That was the problem that lead to the discussions about sysdistrib with Menlo. It later worked out that we could update stats successfully on those tables after the 2nd of the month - had to do with data insertion patterns. But in the emergency, this kludge was a life saver. Art S. Kagel > You will just have to take the hit,code apps to wait for locks and > release locks quickly. > _______________________________________________ Informix-list mailing list Informix-list@iiug.org http://www.iiug.org/mailman/listinfo/informix-list ____________________________________________________________________________________ Cheap talk? Check out Yahoo! Messenger's low PC-to-Phone call rates. http://voice.yahoo.com