I'm currently using DB2 9.1 LUW. Is there a way to tell if a Runstats needs to be run (if there were modified tables done)?

I was thinking that the syscat.tables would give me this information but I'm not seeing anything that tells me if the table has been modified and needs a runstats run since the last runstats.

Could someone help me out here and tell me how they know. Is there any SQL you run to find this out quickly?

Thank you.

CC

You should run runstats when there have been changes to the number of rows caused by inserts and deletes, or changes to overflow characterstics of the rows (caused by updates), or other material changes to the data. The only way you know these things is to run runstats, so you are screwed in an infinite loop.

Just run it once a week, and I would recommend that you use "WITH DISTRIBUTION ON KEY COLUMNS AND DETAILED INDEXES ALL" option. If you have extremely large tables and it is taking too long to do runstats, then use sampling (see the manual). Usually good idea to also run on catalog tables, especially since it will not take a long time to do them.

Get the snapshot for tables and check rows_written.

Andy

Unless a DBA is making minimum wage, or working on a mainframe with charge backs for CPU time, it is almost always much more cost efficient to just run the runstats on some periodic basis rather than trying to figure out when it needs to be run.

I agree. That is what we do, we just runstats on everything once a month whether there were any changes to each table or not. That is far easier to do then to examine if there were any changes and then if those changes are significant for that table to warrant having runstats performed.

Andy