Interpreting LSR pool statistics

CICS® supports the use of up to 255 LSR pools. CICS produces two sets of statistics for LSR pool activity: one set detailing the activity for each LSR pool, and one set giving details for each file associated with an LSR pool. Statistics are printed for all pools that have been built (a pool is built when at least one file that uses the pool has been opened).

You should aim to have no requests that waited for a string. If you do, the use of MXT might be more effective.

When the last open file in an LSR pool is closed, the pool is deleted. The subsequent unsolicited statistics (USS) LSR pool record written to SMF can be mapped by the DFHA08DS DSECT.

The fields relating to the size and characteristics of the pool (maximum key length, number of strings, number, and size of buffers) can be those that you have specified for the pool, through resource definition online command DEFINE LSRPOOL. Alternatively, if some, or all, of the fields were not specified, the values of the unspecified fields are those calculated by CICS when the pool was built.

It is possible to change the LSR pool specification of a file when it is closed, but you must then consider the characteristics of the pool that the file is to share if the pool is already built, or the file open might fail. If the pool is not built and the pool characteristics are specified by you, ensure that these are adequate for the file. If the pool is not built and CICS calculates all or some of the operands, it can build the pool creations of that pool. The statistics show all creations of the pool, so any changed characteristics are visible.

You should consider specifying separate data and index buffers if you have not already done so. This is especially true if index CI sizes are the same as data CI sizes.

You should also consider using Hiperspace™ buffers while retaining a reasonable number of address space buffers. Hiperspace buffers tend to give processor savings of keeping data in memory, using the relatively cheap expanded storage, while allowing central storage to be used more effectively.