topic Re: Roll Memory Vs Page Memory in Application Development and Automation Discussions

Roll Memory Vs Page Memory

Former Member — Fri, 02 Jul 2004 13:29:11 GMT

Could some one explain the difference? Also, which one will get affected by FREEing an internal table ?

Thanks,

Bala

Re: Roll Memory Vs Page Memory

Former Member — Fri, 02 Jul 2004 14:00:40 GMT

Hello Bala,

If you use an typed internal table:

data: itab like standradtable of itab_type. (Table)

data: w_itab type itab_type. (Workarea)

CLEAR: itab --> will kill all entries (No header, becouse there is none, you have to define a working area separately)

REFRESH. itab ---> is not necessary in this case

CLEAR: itab- --> no entries anymore

CLEAR: w_itab --> only the working area is initialized

FREE: itab ---> gives memory free.

If You use a standard itab with OCCURS and Header-Line

data: begin of itab occurs 0,

...

end of itab

REFRESH: itab ---> will kill all entries

CLEAR: itab ---> will init the Header-Line

FREE: itab ---> will release it from memory.

Michael

Re: Roll Memory Vs Page Memory

Former Member — Mon, 05 Jul 2004 14:35:20 GMT

Hello Bala,

> Roll Memory Vs Page Memory… Could some one explain the difference?

Actually it is very difficult to answer this question, because the difference is on the low-level implementation details, which is only known by the developers. Also there are some other memory classes, like Private Memory and Extended Memory.

I’m not the expert in this area, so I just give the extract from documentation, maybe it will be helpful:

“Roll memory is used to store user context specific data as well as internal

mode data….

SAP paging memory is used to store main mode specific data...

Private memory is used to store internal mode data in work process local

memory…

Extended memory is used to store internal mode data in shared memory…

Before R/3 Release 3.0, roll and SAP paging memory were the only memory classes for storing user context data, and SAP paging memory was also used for storing internal mode data...

Currently, extended and private memory are the main resource for storing internal mode data, but roll and SAP paging memory are still used for specific reasons, in particular for storing user context specific data and main

mode specific data.”

> Also, which one will get affected by FREEing an internal table ?

I think it may depend on OS and R/3 release. But probably the (SAP) Page Memory, is not affected because it is not used now for storing program data in user context (internal mode data).

Best Regards,

Mikhail