NCL VSAM Techniques › Control UDB Performance

Control UDB Performance

The techniques used by NCL should ensure efficient processing of VSAM files. Additional performance gains can be obtained by the allocation of additional buffers and processing strings.

This is achieved using the JCL AMP statement sub parameters on the DD statement for the file, or by specification of these options on the UDBCTL command:

BUFNI

The number of index buffers to be allocated by VSAM

BUFND

The number of data buffers to be allocated by VSAM

STRNO

The maximum number of concurrent strings to be used by VSAM

Additional facilities are offered as options on the UDBCTL command. They include:

SIS

Use Sequential Insert Strategy

DEFER

Use deferred writes

LSR

Use Local Shared Resource pool

Important! These parameters should only be changed if the impact on VSAM processing is clearly understood. Inadvertent changes can impose severe storage overheads which could impact the operation of other system components.