Version 4.2.6 for Mainframes
 —  Parameter Reference  —

BPCSIZE - Cache Size for Natural Buffer Pool

This Natural profile parameter is applicable under z/OS and z/VSE only (not for Com-plete and not for IMS TM).

It specifies the size of the buffer pool cache (in KB) for a local Natural buffer pool. It corresponds to the CSIZE subparameter of the BPI profile parameter or NTBPI macro.

Possible settings 0 Size of the buffer pool cache in KB. If BPCSIZE=0 is set, no buffer pool cache is used.
4 to 2097148 (that is, 4 KB - 2 GB) for cache in data space, that is, with C64=OFF.
100 to 58720256 (that is, 56 GB) for cache "above the bar", that is, with C64=ON.

Note:
The specified value is rounded to the next 4 KB boundary for a data space cache and to the next 1 MB boundary for a memory object cache. If the value specified exceeds the possible maximum, the possible maximum value will be taken instead.

Default setting 0 By default, no buffer pool cache is used.
Dynamic specification yes This parameter can only be specified dynamically.
Specification within session no

The BPCSIZE parameter applies to the primary Natural buffer pool (TYPE=NAT, SEQ=0) only. In the case of a global buffer pool, it is ignored. If there is a primary buffer pool with SEQ=0 in NATPARM, only the CSIZE setting of this buffer pool is updated.

In multi-user environments (for example, under CICS), the BPCSIZE parameter affects the very first Natural session only, which initializes the local buffer pool.

The type of storage to be used for the buffer pool cache is determined by profile parameter BPC64 or subparameter C64 of profile parameter BPI or macro NTBPI.

Internally, the BPCSIZE specification is converted into the equivalent BPI specification.

Example:

BPCSIZE=4000
is converted into:
BPI=(TYPE=NAT,SEQ=0,CSIZE=4000)

For more information see Buffer Pool Cache in the Operations documentation.

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