Performance Tuning for Content Manager

234 Performance Tuning for Content Manager

8.6.26 Java interpreter heap size (JAVA_HEAP_SZ)

Impact

DBM - High

Description

This parameter determines the maximum size of the heap that is used by the Java

interpreter that was started to service Java DB2 stored procedures and UDFs.

There is one heap for each DB2 process (one for each agent or subagent on

UNIX-based platforms, and one for each instance on other platforms). There is

one heap for each fenced UDF and fenced stored procedure process. There is

one heap per agent (not including sub-agents) for trusted routines. There is one

heap per

db2fmp process running a Java stored procedure. For multi-threaded

db2fmp processes, multiple applications using threadsafe fenced routines are

serviced from a single heap.

In all situations, only the agents or processes that run Java UDFs or stored

procedures ever allocate this memory. On partitioned database systems, the

same value is used at each partition. The memory is freed when the db2fmp

process (fenced) or db2agent process (trusted) terminates.

Default value (range)

512 (0 - 524,288) 4-KB pages

To update

Run the following DB2 command:

db2 update dbm cfg using JAVA_HEAP_SZ <parameter value>

Our recommendation

We suggest increasing this parameter to 2048. If your are having a memory

bottleneck, consider reducing the value of this parameter. Library Server heavily

relies on stored procedures, which depend on how this parameter is set.

Reducing this value will make more memory available.

8.6.27 Private memory threshold (PRIV_MEM_THRESH)

Impact

DBM - Medium

Description

This parameter is used to determine the amount of an unused agent's private

memory that will be kept allocated. When an agent is terminated, instead of