Specifying maximum keylength for LSR (KEYLENGTH and MAXKEYLENGTH)

The KEYLENGTH parameter in the file definition in the CSD, or the MAXKEYLENGTH in the LSR pool definition specifies the size of the largest key to be used in an LSR pool.

The maximum keylength may be specified explicitly using the KEYLENGTH parameter in the file definition on the CSD, or it may be left to CICS® to determine from the VSAM catalog. For more information about the CSD, see the CICS Resource Definition Guide.

Effects

The KEYLENGTH parameter causes the "placeholder" control blocks to be built with space for the largest key that can be used with the LSR pool. If the KEYLENGTH specified is too small, it prevents requests for files that have a longer key length.

Where useful

The KEYLENGTH parameter can be used in CICS systems with VSAM data sets.

Recommendations

See VSAM tuning: general objectives.

The key length should always be as large as, or larger than, the largest key for files using the LSR pool.

How implemented

The size of the maximum keylength is defined in the KEYLEN parameter in the file definition on the CSD. For more information about the CSD, see the CICS Resource Definition Guide.

Related tasks
VSAM and file control: improving performance
VSAM tuning: general objectives
Defining VSAM buffer allocations for NSR (INDEXBUFFERS and DATABUFFERS)
Defining VSAM buffer allocations for LSR
Defining VSAM string settings for NSR (STRINGS)
Defining VSAM string settings for LSR (STRINGS)
Specifying resource percentile for LSR (SHARELIMIT)
Using VSAM local shared resources (LSR)
Using Hiperspace buffers
Permitting VSAM subtasking (SUBTSKS=1)
Using data tables to improve performance
Using coupling facility data tables to gain performance benefits
Performance aspects of VSAM record-level sharing (RLS)
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