This document describes how to extend the Natural Swap Pool capacity by generating ESA Data Space.
The section covers the following topics:
To achieve a further reduction of the swap I/O operations, you can use
the keyword parameters DATA
and DESA of
the CMPSTART
program to extend the Natural Swap Pool capacity by generating ESA Data Space.
This Data Space will be available to store compressed Natural user threads
whenever the Swap Pool runs out of space.
When this Data Space has been also consumed, a check occurs whether it
is necessary to write user threads from the Data Space to the roll file,
because their life time has ended (see the keyword parameters
DSPCONT
and
DSPLIFE
of macro NTSWPRM).
If there is no free storage space in the Data Space, the swap pool logic will cause the oldest inactive user thread to be written from the swap pool to the roll file.
The generated ESA Data Space is divided into slots of equal size.
If you are using the TP monitor openUTM, you can define the
slot size by appropriately setting the keyword parameter
ROLLTSZ
of the NATUTM macro.
If you are using the TP monitor CICS, the Data Space slot size will automatically take the size of the longest thread.
You can optimize use of the roll file slot by setting the keyword
parameter SWPCOPT=Y
(NTSWPRM macro) to adjust the Data Space slot size.
The size, name and cache size of the swap pool are specified using
profile parameter BPI or the
corresponding macro NTBPI
in the Natural parameter module,
that is, the (NT)BPI settings in effect for the Natural
session initializing the Natural CICS environment are taken.