how often update stats should be run
Hi, we are running IDS 11.5 FC7 on AIX 6.1 How often update statistics should be run against database & in which mode (high, medium, low, distribution only) We have schedule it via OATS tool. Below are the parameters selected for evaluator (Auto Update Statistics Evaluation) AUS_AGE=7 AUS_CHANGE=2 AUS_SMALL_TABLES=1000 AUS_AUTO_RULES=1 AUS_PDQ=20 With this i am not sure statistics are updated in which mode? (High, medium...)
See the Performance Guide for a description of what needs to be done, or just get my dostats utility which implements that protocol. AUS does the following which is most of the protocol: - HIGH on columns that lead an index key - HIGH on the first key column that is different if two or more index keys start with the same column - MEDIUM on all other columns in the table What AUS does not do is a LOW on each complete index key (except single column indexes - for these the HIGH suffices). Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Wed, Jul 27, 2011 at 9:38 PM, SANJAY SHAH <shah@hcma.com.au> wrote: > Hi, > we are running IDS 11.5 FC7 on AIX 6.1 > > How often update statistics should be run against database & in which mode > (high, medium, low, distribution only) > > We have schedule it via OATS tool. Below are the parameters selected for > evaluator (Auto Update Statistics Evaluation) > AUS_AGE=7 > AUS_CHANGE=2 > AUS_SMALL_TABLES=1000 > AUS_AUTO_RULES=1 > AUS_PDQ=20 > > With this i am not sure statistics are updated in which mode? (High, > medium...) > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --20cf307abf012b772804a917c5db
As to how often, as often as needed to maintain useful data distributions. Only you know how often that is. Dostats has options to update a table only if its distributions are more than <N> days old or if the number of rows has changed up or down by <M> percent. In 11.70 update statistics can do this automatically and also monitor the number of inserts, deletes, and updates made to the table since the stats were last generated and only update when it is likely that a given percentage of rows have been modified. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Wed, Jul 27, 2011 at 9:38 PM, SANJAY SHAH <shah@hcma.com.au> wrote: > Hi, > we are running IDS 11.5 FC7 on AIX 6.1 > > How often update statistics should be run against database & in which mode > (high, medium, low, distribution only) > > We have schedule it via OATS tool. Below are the parameters selected for > evaluator (Auto Update Statistics Evaluation) > AUS_AGE=7 > AUS_CHANGE=2 > AUS_SMALL_TABLES=1000 > AUS_AUTO_RULES=1 > AUS_PDQ=20 > > With this i am not sure statistics are updated in which mode? (High, > medium...) > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --bcaec5015ddf73118d04a917f91a