RSDB4UPD

[Former Member]

Good morning,

This morning RSDB4UPD was still active and slowed down my SAP production system. I have read numerous SAP notes wrt this report but have 4 questions.

1.) When is this job suppose to run - all sap.help says is that "The memory-resident database monitor is started automatically for an SAP instance provided the parameter has this value." however the amount of time and resources that this report takes is very intensive so I would not want it to run during production hours

2.) Can I cancel this report if it runs during production hours?

3.) This morning 2 of these reports were running - one from DDIC and one SAPSYS - which one is correct?

4.) Once this report is finished there is a definite performance improvement but the performance remains quite slow and all the work processes run very high CPU - can the system recover or is it better to do a stop and start - which is a problem as this is during working hours.

The server was IPL'd yesterday and I am unsure whether this would have been a reason why these jobs were running during production hours today

Any advice would be greatly appreciated

Anette

[Former Member]

Hi Annette,

We are on V5R3 and had this problems some months ago.

Response time was very bad but as soon as I disabled the monitor everything became normal so the best advice is disable it as soon as you can.

We plan to use plan cache when we upgrade the o/s but for now it is better to lose the statistics and gain performance.

Regards

David

[Former Member]

Hi Guys,

Thanks for the prompt replies - it is greatly appreciated.

The only thing I can think of is that this job causes problems at DB level and hence the high CPU usage. At operating system level the CPU is moving from one WP to the next - and shows bt 37 & 42% on which ever jobs are busy. These jobs normally run at negligable CPU - it is only today that they are using such high CPU... even more problematic is that RSDB4UPD has just kicked in AGAIN! I am putting it off so that it will not run again but I have no idea why it is being triggered.

Unfortunately we have just gone live on SAP and this problem is not helping the confidence levels of my users. Any further advice please? Especially since I will now have to wait for RSDB4UPD to end again.

Anette

[JanStallkamp]

Hi Anette.

SAP Note 382109 shows how to stop the DB Monitor while your system is running.

Depending on your release / support package level you might want to check SAP Note 977676. In that Note I have given a fix for one performance problem related to the DB Monitor.

If you want to keep the DB Monitor running and just want to change the point in time where the RSDB4UPD is running: Goto transaction ST04. Chose menu Edit -> DB Monitor configuration -> Change. There you can set the time interval for that report. Default value is every 300 minutes.

Best regards,

Jan Stallkamp

[Former Member]

Hi Kaushal & Jan,

Thank-you VERY much for both the responses - both were very helpful and I will be looking at the mentioned note in greater detail (and allocating points for the replies).

However I need further assistance please - my response is absolutely atrocious right now. I have even stopped and started my production system but to no avail. Both the jobs finished but the CPU averages bt 97 and 100% - The jobs that use most of the CPU come and go but the CPU remains in the high 90s.

Anette

[Former Member]

Hi,

login with QSECOFR and execute WRKSYSACT and check which job consume more CPU.

regards,

kaushal

[JanStallkamp]

Hi Anette.

I'm a little bit unsure if your problem is really caused by the DB monitor. But if you think you can get along without the information collected by the DB monitor you can just switch it of. I would only suggest that as a short term solution and definitely switch to the plan cache monitor in the near future.

If you want to switch of the DB monitor set the profile parameter as4/dbmon/enable = 0. See SAP Note 1083218 for details. By the way: You can find an overview about platform specific profile parameters [here|https://www.sdn.sap.com/irj/sdn/db4?rid=/webcontent/uuid/109bcadd-2eb2-2a10-e28c-ea506dd607de] [original link is broken];.

Best regards,

Jan Stallkamp

[JanStallkamp]

Hi Anette.

I don't know which i5/OS version you are running. But if you are on V5R4 you should think about using the plan cache instead of the memory based database monitor. This will increase the performance. Please have a look on the [announcement|; given by Christian Bartels here in the forums.

Best regards,

Jan Stallkamp

[Former Member]

Hi,

1.) When is this job suppose to run - all sap.help says is that "The memory-resident database monitor is started automatically for an SAP instance provided the parameter has this value." however the amount of time and resources that this report takes is very intensive so I would not want it to run during production hours

-> you can change time schedule using ST04 In the transaction, choose the menu items Edit>Database Monitor Configuration->Change. You can set the time intervals accordingly.

2.) Can I cancel this report if it runs during production hours?

-> No.

3.) This morning 2 of these reports were running - one from DDIC and one SAPSYS - which one is correct?

-> both are correct RSDB4UPD has two variant once it running in foreground and other is for background.

4.) Once this report is finished there is a definite performance improvement but the performance remains quite slow and all the work processes run very high CPU - can the system recover or is it better to do a stop and start - which is a problem as this is during working hours.

-> you can disable to run this report in PRD server. by set as4/dbmon/enable = 0.

also check following sap notes

Note 977676 - iSeries: Performance improvement in RSDB4UPD

regards,

kaushal