Important Profile Parameters for the Lock Concept (SAP Library

Important Profile Parameters for the Lock Concept

System profile parameters are used to adapt the system as best as possible to the current requirements and resources. A general description of these parameters is provided under Profiles in the CCMS documentation.

The most important profile parameters for updating are described under Main System Profile Parameters for Updating.

The following table describes the main profile parameters associated with the lock mechanism. You can obtain a complete overview by searching for the parameters with the entry *enq* in transaction rz11.

Parameter	Meaning
enque/table_size	Size of the lock table managed by the enqueue server in the main memory. The lock table contains information on which locks are currently held by whom. Lock table overflows are recorded in the system log (see System Logs). In this case, you should check whether the update server is functioning correctly, since the lock table can grow very fast if the update function stops. If no update problems exist, you can use this parameter to increase the size of the lock table. The Computing Center Management System (CCMS) monitors the status of the lock table constantly and outputs warnings if the space available is not adequate. You can check the space available in the lock table by displaying the lock statistics. Unit: kilobyte Default value: 4096
rdisp/wp_no_enq	Number of enqueue work processes that are to run on this instance. Naturally, this parameter is set to 0 on all application servers on which the enqueue server is not running, since only the instance with the enqueue server can contain enqueue work processes. Unit: integer Default value: 0 The parameter on the enqueue instance is usually set to 1, that is, there is only one enqueue work process in the entire system. The parameter, however, can be set to 2-4 in large systems.
enque/backup_file	Complete path to the backup file. This is used to enter the locks, which are transferred to the update, in the lock table again after the enqueue server is restarted (see also Functions of the SAP Lock Concept). Unit: character string (path name) Default value: /usr/sap/<SID>/D<instance no.>/log/ENQBCK
rdisp/enqname	Name of the application server that provides the enqueue service (see Functions of the SAP Lock Concept). The name should be maintained in the default profile so that all application servers use the same name. Unit: character string (instance) Default value: name of the central instance

Note

These are only some of the profile parameters associated with lock management. The default values are designed to ensure optimum system performance and should only be changed by experts.