|
Hi PaulHere is part of an article by Kent Milligan from 2002 - statistics collection was put into the iSeries version of DB2 in 2001 - I was there on the database performance team as a contractor.
"For instance, DB2 UDB for iSeries doesn't provide a RUNSTATS utility for optimizer statistics because its database manager keeps these statistics current at all times."
The link to the whole thing is http://www-128.ibm.com/developerworks/db2/library/techarticle/0204milligan/0204milligan.htmlIndex rebuilds - they go on all the time - unless you delay them with an attribute on the file. And there'd not be much benefit - as I understand it, AIX flavors can have different ways of building indexes, and it matters what you choose. We just don't have that problem on iSeries that I know of.
There are some statistics controls now, I think, but not RUNSTATS. There's the system value QDBFSTCCOL - and it says to look in Information Center for more on that system value and related items. There is automatic and user-requested collection of statistics.
I suppose one could rebuild indexes - delete logicals and recreate - but you take great risk there - shared access paths could be messed up - resulting in overuse of disk space and slower response. The other thing I can think of if RGZPFM over a commonly used logical. Not sure it would matter that much here.
HTH Vern At 08:10 PM 1/18/2007, you wrote:
Ladies and Gentlemen-- We have an application that does most of its work with SQL against i5/iSeries/AS400/S38 databases. We have had some issues, and the recommendation is to run a weekly database maintenance consisting of "rebuilding indexes" and running RUNSTATS against the database. The goal is to make things easier for the Optimizer. We ran the vendor's Database Revitalizer, and it said that index rebuilds aren't needed on this machine; it did show RUNSTATS statements (but I'm not convinced they actually did anything). Everything I'm aware of, and the literature I've been able to dig up, indicates that rebuilding indexes is not required on the i5/etc. machines because the indexes are -always- kept up to date (unless you specify maint(*dly) or something). And I have found some not-quite-definitive statements that indicate that RUNSTATS doesn't work (and isn't required) on the i5/etc. I entered STRSQL, and RUNSTATS is an unknown keyword. I don't know if QSHELL has a RUNSTATS hidden away somewhere. First, comments are welcome; second, I'm looking for links to IBM or other documents that definitely say "RUNSTATS isn't needed," and neither are routine index rebuilds. Thanks for your assistance. --Paul E Musselman PaulMmn@xxxxxxxxxxxxxxxxxxxx -- This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list To post a message email: MIDRANGE-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list options, visit: http://lists.midrange.com/mailman/listinfo/midrange-l or email: MIDRANGE-L-request@xxxxxxxxxxxx Before posting, please take a moment to review the archives at http://archive.midrange.com/midrange-l.
As an Amazon Associate we earn from qualifying purchases.
This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].
Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.
midrange.com
