Live cache is very slow

[Former Member]

Hi All

I know when SAP needs some data to process, It search it from live cache first and if its not available then it goes to database.

1) We use MAXDB to check config of live cache. So its a database or memory.

2) My APO system is very slow. Data cache hit ratio and buffer hit ratio is fine. How should i check more.

3) What is log area and how do i check it.

4) What is data area and how does it effect live cache.

5) What is OMS area and how does it effect live cache.

6) we take backup of log by a batch job. Can we delete all the logs after backup?

7) How should i check which process is victim process.

6) My SAP server and live cache server are on different host. So where should i check running process??

Thanks

Sandeep

[Former Member]

Hi Sandeep,

>> 2) My APO system is very slow. Data cache hit ratio and buffer hit ratio is fine. How should i check more.

You can get the cache statistics by LC10 -> name of database coonection = LCA -> Livecache Monitoring -> LCA -> Current status -> Memory Areas -> Cache

Or on DBMGUI -> Information -> Caches

>> 3) What is log area and how do i check it.

LC10 -> name of database coonection = LCA -> Livecache Monitoring -> LCA -> Current status -> Memory Areas -> Log area -> Used Log area

>> 4) What is data area and how does it effect live cache.

Data area means persistent storage of VSR optimizer. SA stores the data on MAXDB before start the VSR optimizer on SCM system. In short datafiles of MAXDB

>> 5) What is OMS area and how does it effect live cache.

Check the document, below;

http://wiki.sdn.sap.com/wiki/display/MaxDB/OMS+Heap

>> 6) we take backup of log by a batch job. Can we delete all the logs after backup?

You should schedule RSLVCBACKUP with log backup option. You can use these log files when you restore the maxdb database. If you don't want to generate log files by maxdb, check the document below;

http://help.sap.com/saphelp_nw04/helpdata/en/09/f3b43feddd330ee10000000a114084/frameset.htm

But I don't recommend you to delete the log files, before you save them into another media

>> 7) How should i check which process is victim process.

Victim process? Could you clarify the question?

>> 6) My SAP server and live cache server are on different host. So where should i check running process??

You can monitor "vsropsvr" process at the operating system level. Additionally, check LC10 -> name of database connection = LCA -> Livecache Monitoring -> LCA -> Current status -> Kerel threads -> task manager

I hope that everything is clear.

Best regards,

Orkun Gedik

[Former Member]

Hi

1) I am taking full data backup. So can we delete Autolog files which was generated before backup.

2) Suppose live cache is slow due to a batch job. How should i check this batch job among all the active jobs?

[Former Member]

>> 1) I am taking full data backup. So can we delete Autolog files which was generated before backup.

At the end end of the respective backup, you don't need old autolog files anymore. Keep in mind that autolog files that are created after the full backup needs to be keep for the full recovery.

2) Suppose live cache is slow due to a batch job. How should i check this batch job among all the active jobs?

Live cache used by the VSR optimizer. So are you planning to call the optimizer at the background? Could you clarify the question?

Best regards,

Orkun Gedik

[Former Member]

Hi

I am not going to call VSR OPTIMIZER. It is just a question that why live cache is slow. How to catch the process which is making it slow. Cahce statistics is also fine.

Data cache hit ratio is fine.

Thanks

Sandeep

[Former Member]

Hi Sandeep,

Performance problems may be occured not only because of a process, but also the overall system load. For example, because of the no longer physical memory left on the system, swap memory can be used which may lead a performance problem. So, you can investigate the performance problem on LC10 tcode as well.

Additionally, you can monitor db processes on the LC10 as well.

I suggest you read the articles, below;

http://wiki.sdn.sap.com/wiki/display/MaxDB/Performance+Problems

http://wiki.sdn.sap.com/wiki/display/MaxDB/Resource+Monitor

Best regards,

Orkun Gedik