SAP ABAP Data Element DB2PREFDIS (Number of Times Sequential Prefetch Was Disabled)

Hierarchy

☛ SAP_BASIS (Software Component) SAP Basis Component
   ⤷ BC-DB-DB2 (Application Component) DB2 for z/OS
     ⤷ STU3 (Package) Development Class for Database Monitor

Basic Data

Data Element	DB2PREFDIS
Short Description	Number of Times Sequential Prefetch Was Disabled

Data Type

Category of Dictionary Type	D	Domain
Type of Object Referenced		No Information
Domain / Name of Reference Type	DB2DEC20V
Data Type	DEC	Counter or amount field with comma and sign
Length	20
Decimal Places	0
Output Length	27
Value Table

Further Characteristics

Search Help: Name
Search Help: Parameters
Parameter ID
Default Component name
Change document	☐
No Input History	☐
Basic direction is set to LTR	☐
No BIDI Filtering	☐

Field Label

	Length	Field Label
Short	0
Medium	17	Prefetch disabled
Long	20	Prefetch disabled
Heading	0

Documentation

Definition

The counter is computed as:

QBSTSPD + QBSTREE + QBSTWKPD

where
QBSTSPD:
Number of times wequential prefetch was disabled because buffers were not available. In other words, this is the number of times the sequential prefetch threshold is reached.

QBSTREE:
Number of times sequential prefetch is disabled because of an unavailable read engine.

QBSTWKPD:
Number of times sequential prefetch was not scheduled because the prefetch quantity was zero.
Prefetch checks the prefetch quantity. Normally the quantity should be one to eight pages. When the quantity is zero, the value in this field is incremented.

History

Last changed by/on	SAP	20110908
SAP Release Created in	700