Table of Contents

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  1. Preface
  2. PowerExchange Navigator Introduction
  3. Data Maps
  4. Data Maps for Specific Data Sources
  5. Copybooks
  6. Registration Groups and Capture Registrations
  7. Extraction Groups and Extraction Maps
  8. Personal Metadata
  9. Database Row Test
  10. PowerExchange Navigator Examples
  11. Appendix A: PowerExchange Functions for User-Defined Fields
  12. Appendix B: User Access Method Programs
  13. Appendix C: Application Groups and Applications
  14. Appendix D: Data Map Properties
  15. Appendix E: Record, Field, and Table Properties
  16. Appendix F: DTL__CAPXTIMESTAMP Time Stamps
  17. Appendix G: Trace for Creating a Memory Map When Importing a COBOL Copybook

Navigator User Guide

Navigator User Guide

Number of VSAM Data Buffers

Number of VSAM Data Buffers

You can specify the number of I/O buffers that VSAM uses to transmit data between virtual and auxiliary storage.
A buffer is the size of a control interval in the data component. Valid values for the number of data buffers (BUFND) are from 0 through 65535. Minimum value is 1 plus the value specified for STRNO. If you omit STRNO, BUFND must be at least 2, because the default for STRNO is 1.
The minimum buffer specification does not provide optimal sequential processing performance. Generally, the more data buffers that are specified, the better the performance. Additional data buffers can benefit direct inserts or updates during control area splits and benefits spanned record accessing.
Maximum number of buffers is 255, which includes 254 data buffers and one insert buffer.

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