Application Control Heap Size (app_ctl_heap_sz)

Configuration Type

Database

Parameter Type

Configurable

Default [Range]

Database Server with local and remote clients

128 [1-64 000]

Database Server with local clients

64 [1-64 000]

Partitioned Database Server with local and remote clients

256 [1-64 000]

Unit of Measure

Pages (4KB)

When Allocated

When an application starts

When Freed

When an application completes

This parameter determines the maximum size, in 4 KB pages, for the application control shared memory. Application control heaps are allocated from this shared memory.

One application control heap is allocated for each application per database partition for each database partition on which the application is active. The heap is allocated during connect processing by the first agent to receive a request for the application at each database partition. The heap is required to share information between agents working on behalf of the same application at a database partition.

Notes:

1. In a partitioned database environment, this heap is used to store copies of the executing sections of SQL statements for agents and subagents. Symmetric multiprocessor agents (SMP) subagents, however, use applheapsz, as do agents in all other environments.

2. Allocation will take place for an SMP machine that has the parallel_enable parameter set on.

Recommendation: Initially, start with the default value. You may have to set the value higher if you are running complex applications, or if you have a system that contains a large number of database partitions.

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