Live Cache 7.7 Parameters Tuning and Locking Issue

[Former Member]

Hi All,

We have recently installed SAP APO 7.0 system with LiveCache 7.7.07.

Please provide your suggestion for below queries -

1) OMS Data and Data Cache hit ratio was 90% in my LiveCache so we have increased Cache Memory Size(10GB now) and OMS Max Heap Size( 8 GB ).

but now my worry is what other parameters we should consider for good performance in Live Cache System as we have not done any parameter tuning after LiveCache install and it is running on default values of installation.

2) We also see several time Data loading jobs get fail due to lock entry in Live Cache and that lock does not get release till we restart Live Cache Application, Please suggest can we set any paremeter (RequestTimeout parameter is 180 Sec now) or do we have any place like SM12 in ABAP system from where we can remove these Live Cache locks. Under LC10->SQL and OMS lock, We do not see any lock that time.

Please provide your input.

Thanks in Advance.

Shivam

[Former Member · Accepted solution]

Hi Shivam,

Please go through the link and it contains all the parameters for live cache 7.7 with description .

http://maxdb.sap.com/doc/7_7/44/d8ed9cdaba5705e10000000a1553f6/content.htm

Few parameters which are important from performance point of view are as below and should be tuned appropriately.

CacheMemorySize

MaxDataVolumes

MaxLogVolumes

MaxSQLLocks

MaxUserTasks

SessionTimeout

UseAsynchronousIO

UseFilesystemCacheForVolume

Regards

Amit

[Former Member · Accepted solution]

Hi Amit,

Thank you for your input, Tell me one more thing Auto Log Feature is Off in my LiveCache System. Should it be On or what is its impact if it off.

Shivam

[Former Member · Accepted solution]

Shivam,

Switch is On and also switch to auto log backup. Otherwise the Livecache DB will hang when the log area is 100% used up. Also if its production ,please mirror your log volume.

Thanks

Amit

[Former Member · Accepted solution]

Hi Amit,

Thank you..You said for Production we need to mirror log volumes. I am just thinking how can we do it.

Do we need to create addition file system for mirror log files like we have in oracle-

Now we have /sapdb/<SID>/saplog1  ,  /sapdb/<SID>/saplog2 file systems for log files.

How to setup this mirror log volumes and how to make sure live Cache writes logfiles backup at two locations.

Shivam

[former_member229109]

Hello Shivam,

1. First, please use the DB analyzer to check the liveCache parameters settings:

1111426 Parameter check for liveCache/MaxDB instances

then review the notes:

833216 Database parameters SAP liveCache versions 7.5, 7.6 and 7.7

719652 Setting initial parameters for liveCache 7.5, 7.6, 7.7

If you still have additional questions/doubts on the liveCache parameters settings =>

Please create the SAP message and get SAP support.

2. Please use the DB analyzer to find the bottleneck in liveCache.

"We also see several time Data loading jobs get fail due to lock entry in Live Cache and that lock does not get release till we restart Live Cache Application"

This issue should be checked via SAP message.

3.

Please review the SAP notes:

869267     FAQ: SAP MaxDB log area

1377148  FAQ: SAP MaxDB backup/recovery => Please read the answers on questions 4., 5., 6.

The overwrite logging will be switched on during the upload the liveCache during the upgrade SCM system or migration of the liveCache using download/upload procedure.

To avoid the data lost it's recommended to have the logging writer on and activate the auto logbackups after the upgate or migration will be done.

Regards, Natalia Khlopina