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IBM-MAIN - Erfahrungen mit DB2-Qualitätssicherung


Re: DB2 query estimator (was: How Does Your Shop Limit Testing in the Production LPAR)


Bernd Oppolzer <bernd.oppolzer@T-ONLINE.DE>


IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU>


2015.01.10 01:44:35

There is a little topic drift, because the original post was about
CPU problems on production LPARs due to test runs happening there,
and DB2 is not the only reason for CPU consumption of test runs.
In fact, we had problem with very CPU intensive workload (C++
and XML processing), which had nothing to do with DB2 ... but
it was a problem for the parallel running production LPARs, anyway.
So you have to think beyond the DB2 related problems.

But anyway:

I don't quite understand the problem here, because IMO the normal
SQL EXPLAIN command and analyzing the PLAN TABLE results is
sufficient for detecting problems on SQL access. I don't need no
sophisticated and expensive tools that do some fancy pictures on that
for me. SELECTing the PLAN TABLE is IMHO still the easiest and
the best way. And this comes with no additional cost with the normal
DB2 installation.

It is normal practice at the shops I work to do EXPLAIN regularly on all
programs that go into production and to store the PLAN TABLE results
for later trouble shooting ... if there is trouble. The developers at our sites
are trained in analyzing those PLAN TABLEs ... well, at least some of them.
I was doing the necessary DB2 performance classes in the last 20 years.
This works for us.

Kind regards


Am 09.01.2015 um 22:49 schrieb W.B.:
> Speaking as a developer.  A few years back we used to pass all new (or
> troublesome) queries through "Visual Explain".  We LOVED it.  It dramatically
> improved our ability to tune queries before we implemented them.
> Then our internal "software police" took Visual Explain away from us and
> made us use the "supported" product, i.e.  "IBM Data Studio".  What a horribly
> complicated piece of equipment to use for a simple job.  This made even
> attempting to get a simple explain an exercise in frustration.  Developers
> across the board stopped tuning their queries.
> And now they will take Data Studio away from us when we don't use it
> frequently enough because "licenses are expensive and we can see that you are
> not using the product".
> If Visual Explain had a licensed/paid option our company would buy it and
> give us access to it.  Big corporations are extremely averse to using any
> unsupported software, no matter how reliable the vendor is or how "free".  They
> fear it will get incorporated into a production system and that there will
> subsequently be an "Oh Dark Thirty" production incident and there will be no
> vendor support available.
> IBM - Are you listening?  Provide a paid option with support for Visual
> Explain and corporate customers will buy it.
> Sigh ...
> ... Rant over.
>   ____________________________
> W.B.

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