VSAM LSR pool statistics report

The VSAM Local Shared Resources (LSR) Pool Statistics report shows information about buffer pools and is organized by LSR pool. Each entry line of the report represents a subpool. The components of a VSAM cluster will use the buffer subpool with buffers that are at least as large as the component’s CI size. For example, if the data cluster of a file in the Data Set Characteristics report appears as being part of pool number 1 and it has a CI size of 4096, its activity would be reported in the fourth line of the following figure because that subpool has a buffer size of 4096.

VSAM LSR Pool Statistics Report

POOL NO

The identification number of the pool.

TYPE

The VSAM component accessed. These values identify the resource pool:

INDEX	An index component resource pool.
DATA	A data component resource pool.
ANY	Both data and index components may use this resource pool.

STR NO

The number of placeholders defined for the pool. A string is a request to a VSAM dataset requiring positioning within the dataset. For each concurrent file operation, VSAM requires one or more strings.

KEY LEN

The maximum key length for datasets in the pool. If none of the datasets is keyed, Strobe displays 0.

BUF LEN

The size of the virtual and hiperspace buffers in the subpool.

BUFNO

The number of non-hiperspace buffers in the subpool.

HBUFNO

The number of 4K hiperspace buffers in the subpool.

RETRIEVES WITH I/O

The number of I/Os that occurred to bring data into the subpool.

RETRIEVES WITHOUT I/O

The number of retrievals during which the requested data was found in the subpool (also known as lookasides).

WRITES USER

The number of writes that the user initiated.

WRITES NON-USER

The number of writes that occurred because no buffer was available. The program did not initiate these writes.

HIPERSPACE READS SUCCESSFUL

The number of times a hiperspace buffer was successfully read from the LSR hiperspace buffer pool to a local LSR buffer pool.

HIPERSPACE READS FAILING

The number of times a hiperspace buffer was reclaimed and could not be read from the LSR hiperspace buffer pool to a local LSR buffer pool.

HIPERSPACE WRITES SUCCESSFUL

The number of times a hiperspace buffer was successfully written from a local LSR buffer pool to a hiperspace buffer pool.

HIPERSPACE WRITES FAILING

The number of times a hiperspace buffer was reclaimed and could not be written from a local LSR pool to a hiperspace buffer pool.

Important

Hiperspace buffering helps to reduce DASD I/O by using expanded storage for LSR buffers. Hiperspace storage is not byte-addressable. Therefore, to refer to data stored in a hiperspace buffer, VSAM must first move one 4K page at a time to a nonhiperspace LSR buffer pool. The reporting of hiperspace statistics represents movement of buffers to and from hiperspace buffer pools.

Pool n STRING WAITS

If available, the set of string wait statistics for each LSR pool number (identified by n). The statistics only appear for measurement requests that specify the CICS data collection option “Produce Performance Supplement”. For more information on these statistics, refer to the CICS section of the Using-Strobe-options.

MAXIMUM CONCURRENT	The highest number of concurrent I/O requests observed during the measurement session that were waiting for an LSR pool string to become available.
TOTAL	The total number of I/O requests observed during the measurement session that were waiting for an LSR pool string to become available.