Non-VSAM optimization

For non-VSAM data sets, Data Optimizer replaces all low-level I/O functions with its own functions. This replacement provides Data Optimizer with complete control of buffer management and of the physical I/O requests.

The Data Optimizer internal buffer manager satisfies all application I/O requests logically and transparently. Data Optimizer handles non-VSAM optimization by using the following methods:

For sequential processing, Data Optimizer reads large amounts of data with each I/O and overlaps the I/Os to maximize performance, regardless of physical blocking characteristics.
For random accesses, Data Optimizer can retain up to 255 tracks of data in memory to maximize cache-hit performance benefits. It also allows below-the-line buffers to be decreased to assist in virtual storage constraint relief while still providing performance benefits.
For tape data sets, PDS members, and striped data sets, Data Optimizer optimizes data management buffer values.

The following figure shows the non-VSAM performance component of Data Optimizer.

Related topics

Working with Data Optimizer

Glossary

Non-VSAM optimization

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