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Function documentation Sizing of Lock Tables  Locate the document in its SAP Library structure

Use

For a real-time InfoCube, the BI lock server cannot be accessed for the duration of a lock operation. Space on the lock server is restricted. When you implement planning applications in a BI system it is therefore necessary to choose a design that keeps the number and size of the selections as small as possible. The smaller the lock table, the better the response times of the lock server.

You can reduce the size of the lock table by removing characteristics from the list of lock-relevant characteristics in a real-time InfoCube if these characteristics do not serve to divide the selection. These include characteristics which are the same for all users or which have overlapping values. For more information, see Selection of Lock Characteristics.

The following sections contain information about the sizing of the lock table for BI Integrated Planning. These sections explain how you calculate the required memory and set profile parameters accordingly.

Note

For more information about the different options for storing lock tables, see Storage of Lock Tables.

For current sizing information, see SAP Note 928044, BI lock server.

Integration

In profile parameter maintenance (transaction RZ11), you can display the values that are set currently.

Features

Storing Lock Tables on the SAP Standard Lock Server

You use profile parameter enque/table_size to set the size of the lock table on the SAP standard lock server.

The setting

enque/table_size = 25.000

should be sufficient for most systems in which BI planning is used.

You can estimate the number of required lock records more precisely as follows:

●      The number of InfoCubes that are being used actively is IC.

●      The average number of rows in the selection table is Rec. In lock setting maintenance for planning (transaction RSPLSE), you can calculate these numbers for an average user. You display the locked selections on the Display of Active Locks tab page.

●      The number of lock requests for each user is LReq. This number depends on the design of the planning application; number of input-ready queries, number of related planning applications and how often these components request data in change mode.

●      The number of active users is U.

●      The compression factor for a selection table is Compr. This factor is between 5 and 10.

The number of lock records NLCK is then:

NLCK  = IC * U * LReq * Rec / Compr

In SAP lock management (transaction SM12), choose Extras  → Statistics to ascertain the maximum number of lock records that can be stored in the lock table according to the current value of the enque/table_size profile parameter. You find the value in row Lock Entries Table, Size.

Storing Lock Tables in the Shared Object Memory of an Application Server (Default System Setting)

You use the abap/shared_objects_size_MB profile parameter to set the size of the lock table in the shared object memory of an application server.

The setting

abap/shared_objects_size_MB = 200

should be sufficient for most systems in which BI planning is used.

You can estimate the number of required lock records more precisely as follows:

●      The number of InfoCubes that are being used actively is IC.

●      The average number of rows in the selection table is Rec. The actual selections are in the shared object memory twice: once optimized for search access by characteristic and once optimized for access by locked selection (secondary index). The DDIC structure that is used has a width of 207 characters, or 207 byte (or 414 byte in Unicode systems). You can expect approximately one kilobyte per row in the selection table.

●      The number of lock requests for each user is LReq. This number depends on the design of the planning application; number of input-ready queries, number of related planning applications and how often these components request data in change mode.

●      The number of active users is U.

The number of lock records NLCK is then:

NLCK = IC * U * LReq * Rec

The required memory space in kilobyte is calculated by multiplying NLCK by a factor of 2. This is because when a lock is requested, the system makes a copy of the locked selection and retains this for the duration of the collision check.

For information about the memory currently required for the BI lock server, see area maintenance for the shared object (transaction SHMA). Call this transaction on the server with the BI lock table; use CL_RSPLS_ENQ_AREA as the area.

Storing Lock Tables in SAP liveCache

If you want to use the SAP liveCache on the BI lock server, see SAP Note 816730 for the relevant sizing information.

 

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