RE: Update statistic question

Is it true that the more often you run update statistics, the less time it takes to run, because I have a 26GB, 9000 table SAP database, and running update statistics high on the whole database is taking me about 5hrs. I expected it to take much longer than that. Is this about right? Thanks JP > -----Original Message----- > From: Mark D. Stock [SMTP:mdstock@informix.com] > Sent: Wednesday, April 22, 1998 5:50 PM > To: Susan Elliott (ISG) > Cc: 'Informix Mailing List'; Lisa Joubert (ISG) > Subject: Re: Update statistic question > > Susan Elliott (ISG) wrote: > > > > Thanks to all of those who have been answering my questions over the > > last few days !!! Its much appreciated !!! > > > > I have a question about the Update statistics script that we do > > here.... > > > > #### Beginning of script ##### > > set isolation dirty read; > > update statistics medium distributions only; > > update statistics high for table (Table name) (Column Name)> > distributions only; > > {We do the update statistics high on 13635 tables, like above} > > update statistics low;> > ##### End of script ###### > > > > This was set up for me. I have worked out that the high over writes > > the mediums on the tables/ columns specified. It does an update low > > across the whole database. > > Correct. > > > Does this mean that the lows have over written the highs ??? > > No. Low, medium, high is misleading, in that a low has nothing to do > with distributions, whereas both medium and high write distribution > information. > > > Should I change the order of this to low, med and then to the highs > ?? > > Or to med, low and then the highs ?? > > Makes no difference where you put the low in this case. > > > My next stumbling block is the above script runs sequentially and > > takes over 2 days to complete. (we don't run it very often now) So > > that we can run this more often..... and maybe we will get better > > performance... > > Yes... > > > What are my options in breaking up the above script ???? > > Depends on available resources. > > > What do other folk do ??? > > Break it up based on available resources. :-) > > > Can I just break the highs script up and run several at once ??? > > Yes. > > > Can split it up into table types... general ledger, accounts > payable, > > sales etc and do the low, med and then the high on each table types > > ??? > > I would rather look at table location and split it up per disk. > > > How many scripts I run at once ??? What is this dependant on ??? > > Depends on available resources. Available resources. :-) > Start with 2 or 3 updates per CPU. > > > physical cpus ? cpu vps ?? > > Yes. Yes. > > Make sure you have lots of temp dbspace. Set PSORT_NPROCS & > PDQPRIORITY. > Do NOT set DBUPSPACE. > > Hope that helps, > -- > Mark. > > +----------------------------------------------------------+---------- > -+ > |Mark D. Stock - Informix SA http://www.informix.com |//////// > /| > |mailto:mdstock@informix.com FAQ http://www.iiug.org |///// / > //| > | +-----------------------------------+//// / > ///| > | Tel: +27 11 807 0313 |If it's slow, the users complain. |/// / > ////| > | Fax: +27 11 807 2594 |If it's fast, the users keep quiet.|// / > /////| > |Cell: +27 83 250 2325 |Therefore, "No news: travels fast"!|/ > ////////| > +----------------------+-----------------------------------+---------- > -+