Question on "Max Heap size" for Was 70

[Former Member]

In your opinion why the Sap suggestion (note 723909) for the MAx Heap Size parameter is 2GB on machines with 64 bit platform ?

Suppose I have a machine with a lot of RAM, ie more than 20 GB RAM; according the note I should set just 2GB for the Heap size.

It's so dangerous to increase this parameter ?

How I can indicate to the J2EE to use more RAM ?

Or the Oss note 723909 should be read in terms of 'at least 2GB' ?

Regards

[Former Member]

HI

Yes, Ventsi is right !!! I didn't find much difference in the performance after increasing the Heap size to 3GB.

Regards

Shaji

[Former Member]

Hello Marco,

We recommend 2 GB of memory, but you could increase the size up to 3 GB or even 4GB without expected issues. We recommend only to 2 GB per server node, because of the way the Garbage Collection works. Every once in a while, when the tenured area of the memory is exhausted a full garbage collection is triggered. During full garbage collection all processes are frozen and only the garbage collection threads are running. Increasing the heap size increases the time needed to finish the full garbage collection and even though this process will be rarer with more heap, when it happen your server won’t process requests for some time. Therefore instead of increasing the heap size we recommend adding additional server nodes, which will utilize the memory that you have, but will also cover each other if one node is not available to process requests.

You could find information on how to add more server nodes at help.sap.com:

http://help.sap.com/saphelp_nw04/helpdata/en/39/7796e0a7be604ab63c2924045710a8/frameset.htm

Regards,

Ventsi Tsachev

Technology Development Support (J2EE Engine)

SAP Labs, Palo Alto, Ca (USA)

[Former Member]

Thanks for your suggestion.

Please, another question about memory. Suppose to have an Ntw04s Abap+Java instance, where the EP 70 is deployed.

Abap+Java are in the same database.

Using the St04 you can see how is configured the Oracle Sga for the whole instance; using RZ10 you can set the instance parameters for the Abap stack.

Are there parameters related to the J2EE, and in last instance to the EP70, that can be setted in the Abap stack ?

How the performances of the Abap stack can affect the J2EE parameters ?

I mean, using Ep70 on Ntw04s Abap+Java configuration, it is correct to think to keep the Abap stack small as abap buffers and memory areas, in order to increase the J2EE memory parameters ?

All the end users ate the end are

From the J2EE point of views, can I increase the Oracle memory areas dedicated to the J2EE ?

Regards

[Former Member]

up plz...