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13356 - DB/SQL Problem
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DB/SQL Problem
Hi Tom,I can fully agree with you, that you have to decide between this -
and it's not up to me to decide this.
But one last word:
Do you really think, that because of putting the HIPERs on you will
find one occurrence when dealing with support that they tell you:
Yes, you are current, it will be faster.
I would assume, that you are still mostly not current because your
CUM and/or DB-FixPack is not current and that is what they are
looking for.
Please don't understand me wrong: It is not the point, that I
wouldn't install hipers as recommended.
Regards
Volker
--- In DoNotReply@consolut.eu, tom.gainesZu... wrote:
> Hi Volker,
>
> Thanks for clearing up the issue with raja. I was confused and
thought
> maybe I did something wrong, thinking my email went beyond our
group
> somehow, although I don't know how that could have happened.
>
> I appreciate and agree with the great advice for the many things I
asked,
> but I do have one comment on hyper PTF's. We subscribe to the
weekly
> "Alert" notice from IBM which is a service where IBM informs
customers of
> hypers that should go on, or in some cases be removed, from your
system.
> IBM defines these PTF's as fixes to known critical issues that
could
> severely impact the performance of your system.
>
> I know most iSeries shops do not put these on weekly, because the
risk is
> low, but we do for 3 reasons :
> (1) When we report a problem to IBM it is easier and quicker for
them to
> re-create the problem and provide a fix if we are current.
> (2) SAP puts a strain on the iSeries I have not seen with other ERP
> packages - we are trying to be pro-active.
> (3) the quality of the PTF's has improved, including how IBM
handles co
> and pre-reqs.
>
> I know I create other problems with this strategy as you already
pointed
> out. I need to look at it from both sides and decide what's best.
>
> Thanks again to you and all others for your kind and patient
advice. I am
> a long time AS/400 guy but new to SAP and find it both fascinating
and
> frustrating.
>
> Tom
>
>
>
>
>
> "Volker Gueldenpfennig" <volker.gueldenpfennigZe...>
> 03/13/2004 02:01 AM
> Please respond to SAP on System i
>
>
> To: DoNotReply@consolut.eu
> cc:
> Subject: Re: DB/SQL Problem
>
>
> Hi Tom,
>
> it's really not necessary to write to the private adress just
> because of this crazy raja person!
> Either he wants to use this forum, then every mail is "just normal"
> or he can just leave this group via an unsubscribe. So, it should
> not be our problem right now. As soon as we receive a similar mail
> like the one you are referring to, I will remove him manually ...
>
> You are right with the SQL-Pack deletion - especially after
creation
> of indexes!
> I did this at a client for several indexes without restarting SAP
> and therefore without deleting the SQL-Packs. The result was the
> absolute horror in performance, temp-storage use and so on. As soon
> as we deleted the SQL packs, all went back to normal.
> The reason was simple - at least in the review afterwards:
> The optimizer detected that new indexes were available that made
> sense. So, he tried to update the SQL-Packs which was not possible
> as they were locked because of other WPs. Then the optimizer
decided
> to create the SQL packs in QTEMP and used them there. This happened
> in nearly every WP!
>
> What do other clients with SQL-Pack deletion ?
> I think, installing hypers every week in an SAP system is pretty
> unusual. As soon as the system is running stable, I would create a
> strategy on implementing PTFs in a regular timeframe - e.g. all 6-
12
> weeks depending on your needs downtimes etc.
> Then I would order ALL PTFs of the current infoapar and apply them
> to test and 2-3 weeks later to PRD. You have the following
> advantages:
> - you might see problems in test already
> - you might hear through this group on problems and can stop the
> process as you install only 2-3 weeks old PTFs
>
> Your strategy to install hypers every week is not that good in my
> eyes. Even when all PTFs should be "independent" except the pre-
and
> co-reqs this is not the total truth. PTFs in an SAP environment
> have "to fit together". This happens with installing all of the
> current - or any older - infoapar. One example of a customer a 2-3
> years ago:
> They were running fine with very old PTFs. Then they installed the
> CUM - but just the CUM. This resulted in many SQL errors
> (SQL0901, ...) because the old DB fixpack and the very new CUM
> didn't fit - even when this should not be the case - nobody can
> garanty for the correctness of such a configuration.
>
> What doing with deletion of thew SQL-packs:
> You are mostly right, that the first time the report is called the
> SQL pack is prepared. Some few SQLs are prepared before already as
> they are "common" (in lib r3sidx0000). It is correct, that this is
a
> bit bad for the responsetime in the first hours, but your restart
> every night is very bad as well and all users that come to the
> company early should see a worse performance than the ones starting
> later - I would guess 1-2 hours should be "suffering".
> If you now change your backup strategy to restart SAP max once a
> week or even all 2-5 weeks, you should gain performance here. If
you
> then install all 6 weeks PTFs and delete the SQL packs then, the
> users shouldn't complain too much on that monday.
>
> Buffer filling at SAP is something the user initiates - except the
> ABAP buffer, that is prefetched. So, your normal workload will
> result in useful filled buffers for you. You should have an eye on
> swaps in ST02. On iSeries, they should be normally at 0, because
you
> can increase all buffers very hihg - at least as of 4.6x.
>
> Backup with SAVR3SYS:
> the savr3sys has the advantage that it covers everything that might
> be of interest on one page. But, you can use SAVLIB with save-while-
> active (e.g. 1800s) as well, because SAVR3SYS calls SAVLIB and SAV
> internally. If you decide for SAVR3SYS ensure, that you are using
> the option *RUN an NOT *DSCDB, because this is not working properly
> and normally not necessary either.
>
> Hope this helps,
>
> Volker
>
> ==============================
>
> Hi Volker,
>
> In case the email from raja "don't send mail to me" was meant for
> me, I'm
> sending this directly to you instead of the group. Please reply to
> "tom.gainesZu..." if you don't mind.
>
> I found the guidelines for deleting SQL packages in the
Implementing
> SAP
> R/3 Redbook - it fully supported what you said earlier. I think
> that's
> certainly a part of our problem - we need to delete the packages
> more
> often. We put hypers on weekly, perform occassional client copies,
> create
> new indexes when needed, etc. The interesting question is why have
> the
> errors started only recently? - I'm sure IBM will help us with some
> PTF's.
>
>
> We have been reluctant to delete packages too often because of the
> performance hit to our users. It's my understanding that the paths
> do not
> rebuild until the user initiates the job that needs them and it can
> be
> very slow with the first initiation only.
>
> So that's my question - how do most companies handle the
performance
> issue
> - simply tell their users it's due to required maintenance?
>
> Thanks also for your comments on the IPL and online backup - it
> makes
> sense - does the buffer filling and ODP opening happen right after
> the IPL
> or when the users first sign on?
>
> For the online backup were you referring to SAVR3SYS?
>
> I am very grateful for all your help! - sorry about the length of
my
> messages.
>
> Tom
> --- In DoNotReply@consolut.eu, "Volker Gueldenpfennig"
> <volker.gueldenpfennigZe...> wrote:
> > Hi Tom,
> >
> > that sounds really interesting!
> > This should be not the case in my eyes if the workload over the
> week
> > should stay similar - which could be checked in ST03N as well.
> >
> > I wouldn't argue with the joblogs, because these messages could
be
> > OK and it would be normal, that as older as the SQL-Packs are and
> > the more tables are in ODPs open, the more of these messages
might
> > occur.
> >
> > Regards
> >
> > Volker
> >
> > --- In DoNotReply@consolut.eu, tom.gainesZu... wrote:
> > > Hi Volker,
> > >
> > > Thanks for the info. I'm checking with our Basis Administrator
> on
> > the
> > > ST03N statistics but from our OS/400 monitoring there was a
> > definite
> > > gradual increase in CPU utilization with the passing of time
> after
> > SQL
> > > packages are deleted. For example, if packages were deleted on
> a
> > weekend,
> > > Monday and Tuesday would show very few SQL 7917 errors and
> typical
> > CPU
> > > use. By Friday, there would be many errors in our job logs and
> an
> > > increase of 20 - 30% in CPU utilization.
> > >
> > > We have not had an increase in number of users.
> > >
> > > Tom
> > >
> > >
> > >
> > >
> > >
> > > "Volker Gueldenpfennig" <volker.gueldenpfennigZe...>
> > > 03/12/2004 12:56 AM
> > > Please respond to SAP on System i
> > >
> > >
> > > To: DoNotReply@consolut.eu
> > > cc:
> > > Subject: Re: DB/SQL Problem
> > >
> > >
> > > Hi Tom,
> > >
> > > I forgot to ask:
> > > Did your responsetime change in ST03N ?
> > > Are you having more users on it ?
> > > Do you think, that the performance degrades after several days
> or
> > > weeks and gets recovered with deleting the SQL-Packs ? (because
> > this
> > > shouldn't be the case)
> > >
> > > Regards
> > >
> > > Volker
> > >
> > > e-mail: volker.gueldenpfennig "at" easymarketplace.de
> > > web: www.easymarketplace.de
> > >
> > > --- In DoNotReply@consolut.eu, tom.gainesZu... wrote:
> > > > Hi all,
> > > >
> > > > From an appreciative long-time viewer, here's my first
> posting -
> > > >
> > > > For about the last 2 months we have been getting SQL
> > 7917 "Access
> > > Plan Not
> > > > Updated" errors on our production system (4.6c). CPU
> > utilization
> > > has
> > > > increased but not enough to hurt us much, although there have
> > been
> > > > complaints of slow response time on certain jobs. We are
> > running
> > > an 830
> > > > with 3 processors and 10gb memory allocated to PRD. We have
> > > deleted the
> > > > SQL packages several times which temporarily cleans up the
> > problem
> > > but the
> > > > frequency and impact of the error then builds up again until
> we
> > > delete the
> > > > packages again.
> > > >
> > > > We opened a PMR with IBM and applied the PTF's they created
> for
> > > us. We
> > > > applied the latest cum at their request. We are also current
> on
> > > the fixes
> > > > recommended on the SAP infoapar. We now have a new error MCH
> > 6802
> > > > "Literal Values Cannot be Changed" and the SQL 7917 error has
> > > resurfaced
> > > > again. We also had a MCH 3601 error "Pointer Not Set for
> > Location
> > > > Referenced" which caused one of our SAP WP's to overload,
> > requiring
> > > an IPL
> > > > to recover. I don't know if the pointer error is related to
> the
> > > others or
> > > > not.
> > > >
> > > > IBM is doing what they can to get to provide fixes but it
> takes
> > > time. My
> > > > question to the group is has anyone experienced these errors,
> > how
> > > much
> > > > should I worry about them, and what did you do to remedy
them.
> > > Our
> > > > kernel level is old (1313) because we are in a FDA regulated
> > > environment
> > > > and updates require a special process. Is the old kernel a
> > factor
> > > and if
> > > > so, why? Until now, we have not had performance issues.
> > > >
> > > > Thanks much for any feedback.
> > > >
> > > > ____________________________________________________
> > > >
> > > > Tom Gaines
> > > > Data Center Supervisor
> > > > Upsher-Smith Laboratories, Inc.
> > > >
> > > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
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