This part describes the use of the message buffer pool.
Note:
The message buffer pool is available under z/OS.
The following topics are covered:
The message buffer pool is a cache memory which is used to store the Natural system messages and the user texts.
Before an error message is output, Natural first checks whether the corresponding message text is available in the message buffer pool. If so, this text is output. Otherwise, the error message would be read from the database, and would be stored in the message buffer pool.
The message buffer pool is available only as a global buffer pool. Its use is optional,
and is controlled by the Natural profile parameter BPI
or the corresponding macro NTBPI
.
When used, the message buffer pool is allocated in a data space.
The following prerequisites must be met if you want to use the message buffer pool:
The module NATMBPvr
must have been linked
into an Authorized Program Facility (APF) library; see the corresponding step
in Installing Natural on
z/OS in the Installation for z/OS
documentation.
The message buffer pool must have been created and started; see the corresponding step in Installing Natural on z/OS in the Installation for z/OS documentation.
The keyword subparameter TYPE
of profile parameter BPI
or macro NTBPI
must be set to MSG
.
The message buffer pool is operated by the program
NATMBPvr
which must be executed from within an
Authorized Program Facility (APF) library.
The following topics are covered below:
Note:
In the following document, vrs
or
vr
represents the relevant version of the
product. For information on product versions, see Version in the
Glossary.
The functions available from
NATMBPvr
(see also Function Parameters) are
activated in that they are
provided by a parameter card (PARM=
),
read from a file (see below),
or supplied by the MODIFY
operator command unless
NATMBPvr
has not been terminated.
NATMBPvr
expects the first command in the
parameter field (PARM=
) of the EXEC
statement.
You may enter:
one of the functions described in the section Common Message Buffer Pool Operating Functions,
or a reference to an input file with
CF=<dd-name>
, where
<dd-name>
represents a DD name
defined in the JCL.
Only "card image" files are supported; that is,
RECFM=F,LRECL=80
, and only the first 72 bytes of the input record are
honored.
Every record included from the input file represents a command.
Blank records or records prefixed with an asterisk (*) are ignored.
A file is processed until End-Of-File (EOF).
Example: PARM='CF=SYSIN1'
If the parameter field is not supplied or blank, the commands will be read from file
SYSIN
by default.
It is only possible to enter one function at a time at the console, or one function per line using the command file, otherwise an error message will be returned.
Each command received from parameter card, from file input or from operator console input is displayed on the operator console.
To start the program NATMBPvr
, either start a
started task or submit a job which executes
NATMBPvr
.
The program NATMBPvr
is stopped by using the
TERMINATE
function (see Common Message Buffer Pool Operating
Functions) or, in case of emergency, by using the
CANCEL
operating program.
The following examples show sample batch jobs for creating and terminating a global buffer pool.
Note:
In the following examples, v
,
vrs
or
vr
represents the relevant version of the
product. For information on product versions, see Version in the
Glossary.
//MBPSTART JOB //* //* Starts a message buffer pool with the name NATvrMBP and //* a size of 10 MB. //* The subsystem used is NATv. //* //STEP EXEC PGM=NATMBPvr,PARM='BP=NATvrMBP,SI=10' //SETPLIB DD DISP=SHR,DSN=USER.APF.LINKLIB
//MBPRES JOB //* //* Starts a message buffer pool with the name MBP and a default size of //* 100 MB. The subsystem used is SAGS. //* //STEP EXEC PGM=NATMBPvr,PARM='BP=MBP,S=SAGS'
//MBPSTRT2 //* Read commands from SYSIN1: //* //* Start 2 message buffer pools (subsystem ID Nvrs) with name //* NATMBP1 - size=1000MB //* NATMBP2 - size=2000MB //* If the buffer pools should shut down, send operator command MODIFY with //* parameter "CF=SYSIN2" to execute the corresponding FSHUTs. //* //STEP EXEC PGM=NATMBPvr,PARM='CF=SYSIN1' //SYSIN1 DD * CREATE,BP=NATMBP1,S=Nvrs,SI=1000M CREATE,BP=NATMBP2,S=Nvrs,SI=2000M SHOWBP S=Nvrs //SYSIN2 DD * FSHUT,BP=NATMBP1,S=Nvrs FSHUT,BP=NATMBP2,S=Nvrs //*
The following functions are available:
Note:
The function names can be abbreviated. It is sufficient to use the first character
only, for example T
for TERMINATE
.
This function prints a list of the available syntax commands and, where applicable, the default values of the function parameters.
This function creates a message buffer pool with the specified parameters.
The message buffer pool with the specified parameters is deallocated.
The message buffer pool operating program is terminated. Prior to that, all active message buffer pools are deallocated.
Displays all Zaps applied to the message buffer pool operating program.
The functions of the message buffer pool operating program can be controlled with the aid of parameters. These parameters can be specified in any sequence. They can be abbreviated.
The following parameters are available:
BPNAME |
Name of message buffer pool. |
BPLIST |
Name of the preload list (optional). |
SUBSID |
Natural subsystem ID. |
SIZE |
Size of the message buffer pool. |
Note:
The underlined part of the parameter name marks the shortest possible
abbreviation.
BPNAME=value
specifies the name of the message
buffer pool to be created.
Value | Explanation |
---|---|
8 bytes | The name of the message buffer pool.
Note: |
MTBP |
This is the default value. |
BPLIST=value
specifies the name of the optional
preload list.
Value | Explanation |
---|---|
8 bytes | The name of the preload list.
Note: There is no default value. |
SUBSID=value
specifies the ID of the Natural
subsystem.
Value | Explanation |
---|---|
4 bytes | The ID of the Natural subsystem.
Note: |
NATv |
This is the default value, where
v is the first digit of the current
Natural version.
|
SIZE=value
specifies the size of the message
buffer pool.
Value | Explanation |
---|---|
1 - 2000 MB | The size of the message buffer pool. |
100 |
This is the default value. |
Refer to Message Buffer Pool Messages in the Messages and Codes documentation.