SAP ABAP Data Element CHUNKWRITE (Writes resulting from a checkpoint)

Hierarchy

☛ SAP_BASIS (Software Component) SAP Basis Component
   ⤷ BC-DB-INF (Application Component) Informix
     ⤷ STUI (Package) Informix Database Monitor

Basic Data

Data Element	CHUNKWRITE
Short Description	Writes resulting from a checkpoint

Data Type

Category of Dictionary Type	D	Domain
Type of Object Referenced		No Information
Domain / Name of Reference Type	SINT4_NOS
Data Type	INT4	4-byte integer, integer number with sign
Length	10
Decimal Places	0
Output Length	10
Value Table

Further Characteristics

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No Input History	☐
Basic direction is set to LTR	☐
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Field Label

	Length	Field Label
Short	0
Medium	0
Long	0
Heading	0

Documentation

Definition

Chunk writes are performed by page cleaner threads during a checkpoint, or when every page in the shared memory buffer pool is modified. Chunk writes are the most efficient types of writes available to Online. Chunk writes are sorted writes, which minimizes head movement (disk seek time) on the disk and enables the page cleaners to use the big buffers during the write if possible. In addition, since user threads must wait for the checkpoint to complete, the page-cleaner threads are not competing with a large number of threads for CPU time. As a result, the page cleaner threads can finish their work with less context switching.

History

Last changed by/on	SAP	20010130
SAP Release Created in