SYSLOCKS overflow

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now
has twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log
to explain it. Can anyone give me advice as to how find out what is
using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
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Normal

Normal
Re: SYSLOCKS overflow
"Have you looked for no commits on batch updates? Or a commit interval
set too high?

Dick

Richard Pierce
[phone]
[e-mail]

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now
has twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log
to explain it. Can anyone give me advice as to how find out what is
using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

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Re: SYSLOCKS overflow
"Interesting, Dennis. That often happens on all of our production CV's. It can take up to 30 minutes (the inactive interval) to get everyone off. How does varying the areas to retrieval first improve this situation?

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now
has twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log
to explain it. Can anyone give me advice as to how find out what is
using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
IDMS Public Discussion Forum
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Normal

Normal
Re: SYSLOCKS overflow
"Look for a long orphan chain in an indexed set. They can chew up SYSLOCKs
very fast and COMMIT logic won't help.

Mark Grindstaff

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have increased the number of SYSLOCKS defined several times, so that it now has twice as many as our most heavily-used CV (which does not have this problem). But it is still not enough. I can't see anything on the log to explain it. Can anyone give me advice as to how find out what is using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"One of my clients performs all the daily backups with the system still
available in retrieval mode.

The way that we get all the areas to go to retrieval is to run a UCFBATCH
job and vary the VTAMLINE offline, vary the areas retrieval and then vary the
VTAMLINE back online.

It works every time, of course it knocks all the users off but, they are
used to it as they know the backups start at a certain time.

Unfortunately if you only have a UCFLINE you can't do it as the UCFBATCH Job
will need a PTERM/LTERM, but you could always set up a special UCFLINE just
for yourself.

Bill Allen
[phone]


In a message dated 4/22/2008 3:15:55 P.M. Eastern Daylight Time,
[e-mail] writes:

Interesting, Dennis. That often happens on all of our production CV's. It=
can take up to 30 minutes (the inactive interval) to get everyone off. Ho=
w does varying the areas to retrieval first improve this situation?

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have increased the number of SYSLOCKS defined several times, so that it now has twice as many as our most heavily-used CV (which does not have this problem). But it is still not enough. I can't see anything on the log to explain it. Can anyone give me advice as to how find out what is using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"The system lock limit is currently set to 5000, for both online and external tasks. Is this considered high, low, average?

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have increas=
ed the number of SYSLOCKS defined several times, so that it now has twice a=
s many as our most heavily-used CV (which does not have this problem). But=
it is still not enough. I can't see anything on the log to explain it. C=
an anyone give me advice as to how find out what is using so many SYSLOCKS,=
or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]





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Normal

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Re: SYSLOCKS overflow
"We utilize exit 20 to monitor resource (including SYSLOCKS) overflow.
From the comments in the exit source:

***********************************************************************
*** THIS IS A COPY OF DBABUX20 FOR THE CV11(PROD) REGION ONLY. *
*** TO BE USED FOR THE PRODUCTION TESTING. *
* *
* THIS USER EXIT 20 HANDLES RESOURCE LIMIT OVERFLOWS. *
* IT IS INVOKED BY RHDCLIMT WHENEVER A LIMIT IS FOUND TO BE *
* EXCEEDED. THE EXIT DOUBLES THE LIMIT AND PASSES RETURN *
* CODE 8 BACK IN ORDER TO GENERATE MESSAGE DC244002. *
* THE MESSSAGE DESC IS LISTED BELOW: *
* *
DC244002 TASK: <TASK-CODE>; <RESOURCE-TYPE> RESOURCE LIMIT EXCEEDED 
* *

Something like this could help determine who's creating the locks.

Dick

Richard Pierce
[phone]
[e-mail]

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now
has twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log
to explain it. Can anyone give me advice as to how find out what is
using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"You probably have a batch program that is not issuing commits and
freeing resources. You may want to search through your stats before this
program locks up your CV in the middle of the night. If this keeps
hogging resources, you might end up with all your journals full or other
nightmares.


Dan Hall
GE Capital Solutions
Database Administrator

T 513.217.5060
E [e-mail]
www.ge.com/capitalsolutions/

Lee Farm Rd.
Danbury, CT 06810
General Electric Capital Corporation

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have increased the number of SYSLOCKS defined several times, so that it now has twice as many as our most heavily-used CV (which does not have this problem). But it is still not enough. I can't see anything on the log to explain it. Can anyone give me advice as to how find out what is using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"We cycle the CV on Sunday.

Last week:
# TIMES OVFL = 4
# OVFL GETSTG = 88
OVFL SIZE HWM = 777600

This week (so far):
# TIMES OVFL = 1
# OVFL GETSTG = 14
OVFL SIZE HWM = 241920

On this CV, I never see it when it is happening.

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now
has twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log
to explain it. Can anyone give me advice as to how find out what is
using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: ABEND code UNGA
"Buz - does your site have ASG-Prealert? release 4.5 allows the exception
monitor to specify its own abend code when exceeding a threshhold causes a
task to be abended by ASG-Prealert .....
just a thought


Chris Hoelscher
Senior IDMS & DB2 Database Administrator
Humana Inc
502-476-2538
[e-mail]



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Normal

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Re: SYSLOCKS overflow
"Concern, like beauty, is in the eye of the beholder.
It all depends on what is causing the overflow.
Is the overflow present when you detect it, or has it come and gone?
If it's come and gone, then it may just be a heavy batch cycle and changing
the syslocks could cause it to go away. On the other hand, if it is during
the batch cycle, once the overflow is allocated there isn't a significant
amount of overhead allocated to the overflow during the processing cycle,
only at the FINISH and/or COMMIT point of time when we are freeing locks.
During the free process, once we've freed the duplicates, unnecessaries,
etc, we check to see if the overflow storage is completely unused. If it is,
then we return the overflow storage to the storage pool. If it isn't we
continue using it.
How many time in overflow, overflow allocations and highwater mark?

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now
has twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log
to explain it. Can anyone give me advice as to how find out what is
using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"I would say it is relatively low Kay.

You could try increasing the SYSLOCKS to something like 20K and see what
impact that has.


Hal Govan
Senior Database Administrator
Reed Elsevier - Technology Services
[e-mail]
Phone: [phone]

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have increased the number of SYSLOCKS defined several times, so that it now has twice as many as our most heavily-used CV (which does not have this problem). But it is still not enough. I can't see anything on the log to explain it. Can anyone give me advice as to how find out what is using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"Hello Kay:

I have a customer that I have continually raised from 100,000 to 210,000 and
I am still seeing overflows. Of course it is much less than when it was
100,000. We maybe get six or seven a day now. Unfortunately this client is
still running 12.1 and any increase of SYSLOCKS still has an affect on below
the line storage.

Bill Allen
[phone]

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increas= ed the number of SYSLOCKS defined several times, so that it now
has twice a= s many as our most heavily-used CV (which does not have
this problem). But= it is still not enough. I can't see anything on
the log to explain it. C= an anyone give me advice as to how find out
what is using so many SYSLOCKS,= or how to determine when the overflow
occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"Kay, do you have system lock limits defined in your sysgen ?

If not, this might be an ""opportunity"" to set some fairly high limits
and then start backing them down until you see something ABEND.

If so, perhaps stepping them down as above might point to the problem
app.

At that point, you then have a choice of fixing the application or the
limit and SYSLOCKS values . :-)


Hal Govan
Senior Database Administrator
Reed Elsevier - Technology Services
[e-mail]
Phone: [phone]

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now has
twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log to
explain it. Can anyone give me advice as to how find out what is using so
many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"They are listed as ""class"". What does it mean?

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now
has twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log
to explain it. Can anyone give me advice as to how find out what is
using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

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Re: SYSLOCKS overflow
"Hi Kay we have a set time when we vary our areas offline each night so
we have at the most two people on and we have our sysgen set to
Retrieval nolocks, we have very short rununits in update, when the user
is finished the update the area is them allowed to vary to retrieval as
there are no more locks being held then we can vary the areas offline.
The areas in our subschemas are set to Default usage mode retrieval and
the individual programs ready the areas that they need in update mode.
We only have one application that runs CV Batch update against it and
these batch jobs are done well before this application areas are varied
offline.
The other applications only have online update or Batch Local
We did a lot of testing on our test CV which has very small databases
and we
Set the syslocks high and we could make it overflow just by varing the
database offline when someone else had some of the areas readied in
update. WE could not make it go into overflow by using an application
program, to small of a database.
Kay if it is an application program when you did the DCMT D LOCKS STAT
it would show up as a session overflow

Dennis Robock
Alberta Department of Energy

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have increased the number of SYSLOCKS defined several times, so that it now has twice as many as our most heavily-used CV (which does not have this problem). But it is still not enough. I can't see anything on the log to explain it. Can anyone give me advice as to how find out what is using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"Hi Kay

What do you see when you do a
DCMT D LOCKS STAT when this occurs
Does the overflow show up as session, class or something else.

Dennis Robockd
Alberta Department of Energy

[ca.portal.admin]

One of our production CV's gets periodic SYSLOCK overflows. I have
increased the number of SYSLOCKS defined several times, so that it now
has twice as many as our most heavily-used CV (which does not have this
problem). But it is still not enough. I can't see anything on the log
to explain it. Can anyone give me advice as to how find out what is
using so many SYSLOCKS, or how to determine when the overflow occured?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: [phone] Fax: [phone]
Email: [e-mail]
"
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Normal

Normal
Re: SYSLOCKS overflow
"Kay

Do you vary areas offline during the night and can someone still be
logged onto the application?
We see this occasionally when someone is still
Logged on the application database when we vary the areas offline to run
our Local batch
The way we found to fix this is to Vary the areas retrieval and then a
couple minutes later vary the areas offline

We saw this occur once we migrated to release 16.0 SP1
We never saw this in previous releases.

We raised this issue on the list a couple of years ago.

Dennis Robock
Alberta Department of Energy