Use Shared Memory Manager for Extract

Oracle GoldenGate Extract starts a separate task, or job, from the WLM to monitor shared memory usage. This job is a minimal task that runs in MVS, but it is not a WLM. The username of this script starts under must have permissions to execute when starting from the WLM (usually using something like RACF). This monitored shared memory consists of a small 48 to 64 byte ECSA area, and a larger 64-bit area based on the Extract buffer size.

Specific fields in shared memory get updated for every read performed by the Extract. These fields are updated whether or not the script returns any data. The monitor checks those fields to ensure the Extract has not become inactive. If the Extract is inactive, the shared memory is released, and the monitor ends. You can control the Memory Manager using the remote_memory_options parameter in the Extract’s parameter file.

You can specify multiple sub-parameters to configure the monitor task. You can configure the wait interval and inactive time the monitor uses by specifying sub-parameters of the remote memory options, as shown in the following example:

remote_memory_options wait_interval 2000 inactive_time 01:00

The wait interval is expressed in hundredths of seconds in the example and causes the monitor to wait 20 seconds between each memory check. If the monitor has checked for 1 hour (format HH:MM) and the Extract is still inactive, then the monitor will shut down after releasing the shared memory. If the Extract returns to an active state during that hour, the monitor will reset its state and continue monitoring.

The wait_interval can have values from 100 to 6000 and the default is 1000. The inactive_time can be from 00:10 to 12:00 and the default is 00:30. If the monitor does not start properly, the Extract displays a warning message in the Extract report and the Extract continues the processing. The Extract will attempt to release ECSA memory when it shuts down.

The remote memory parameter has three options to make this feature work. The syntax for these parameters is:

task_procedure proc name
task_library proc library
task_setup task setup program

Example:

remote_memory_options task_procedure OGGPR001 
remote_memory_options task_library TEST.PROCLIB
remote_memory_options task_setup OGGJT001

You may specify multiple options in a single command, as shown below:

remote_memory_options task_procedure OGGPR001 task_library TEST.PROCLIB task_setup OGGJT001

Note:

The values for the remote memory parameter are case insensitive.

The default values are procedure name OGGPR001 and the task setup program OGGJT001. There is no default for task library as the procedure might be installed in one of the MVS system default procedure libraries. The task library parameter is only needed if the procedure is not in a system default library.

The memory task will start with a simple JOB card and an EXEC procedure name with parameters passed from the Extract. Some z/OS systems may require various other parameters on the job card. The JOB parameters can also be modified using the remote memory parameter, as shown in the example given below.

remote_memory_options task_jobname [valid MVS job name (see below)]
remote_memory_options task_acct_info [valid MVS acct value (see below)]
remote_memory_options task_programmer [valid MVS programmer name, Can use single quotes]
remote_memory_options task_class [valid MVS job class A to Z or 0 to 9]
remote_memory_options task_msgclass [valid MVS msgclass A to Z or 0 to 9]
remote_memory_options task_msglevel [valid MVS message level n or (,n) or (n,n)  n=valid digit]
remote_memory_options task_priority [valid MVS priority 0-15]

You can specify the JOB name using two valid characters and an asterisk, such as AA*. The default JOB name is GG*. The asterisk is replaced by six random numbers when it is specified. Otherwise, if you specify a one to eight byte character name, it must be a valid MVS job name.

Specify account values in any of the following valid MVS formats:

OTXI
‘MY ACCT’
(ACCT,1234,ABC)

For parameters, like acct_info and programmer, that allow special characters, enclose those in single quotes. In addition, the MVS rules about using double single quotes or ampersands within quotes continue to apply. The Extract does minimal validation for these parameters and leaves the complete validation to the MVS process. Extract will accept the first one if you specify duplicate parameters and ignore any duplicates.

A sample procedure JCL file will be included in the zOSPrograms.zip file. This JCL does not replace the WLM procedure. The monitor, created in the WLM, uses the JCL to run in MVS. A JCL procedure allows more flexibility if you add commands or JCL that support job output archiving or other procedures.

Note:

During installation and setup for the memory manager, temporarily turning off the memory manager may be necessary when you must wait for RACF setup issues, initiator usage, job class usage, or other similar issues related to the memory manager.

The Extract will operate in its legacy mode in this instance and release ECSA, and the 64-bit shared memory. The Extract shows the release of shared memory at the end of the Extract report.

Oracle does not recommend this as a permanent solution. When used, the user is responsible for monitoring the release of ECSA and 64-bit memory. The parameter to turn on this feature begins with an underscore to remind the user that the system is running in this mode. Other remote memory options can be left in place and used by removing the option to turn memory management off. The remote memory management parameter defaults to being on, and it is specified as shown:


remote_memory_options _remote_memory_on
remote_memory_options _remote_memory_off

The JCL has the following format:

//*==================================================================== 
//* EXAMPLE JCL FOR RUNNING THE COMMON MEMORY MONITOR PROCEDURE
//* ADDRESS SPACE NEEDING AN AUTHORIZED LOAD LIBRARY
//* NOTE: THE PROGRAM OGGMT001 CAN BE RENAMED IN THE LIBRARY BUT THE
//*       NEW NAME MUST MATCH THE PROGRAM NAME IN THIS JCL
//*==================================================================== 
//OGGDSNNA PROC RGN=0K TR=,EX=,MEM=,LEN=,SEC=,DUR=,VER=
//OGGDSNNX EXEC PGM=OGGMT001,REGION=&RGN,TIME=NOLIMIT,
// PARM='&TR &EX &MEM &LEN &SEC &DUR &VER'
//*--------------------------------------------------------------------
//* REPLACE &PREFIX.**.AUTHLOAD LIBRARIES WITH SITE SPECIFIC FILE(S)
//* ALSO REPLACE THE CEE LIBRARY WITH SITE SPECIFIC FILE
//* DSNN COULD REPRESENT A DB2 SPECIFIC LOAD LIBRARY IF ONE EXISTS
//*--------------------------------------------------------------------
//STEPLIB  DD DISP=SHR,DSN=&PREFIX..WLMDSNN.USER.AUTHLOAD
//         DD DISP=SHR,DSN=CEE.SCEERUN
//SYSPRINT DD SYSOUT=*
//SYSOUT   DD SYSOUT=*

Modify the libraries marked with PREFIX so that they work in your system. If you renamed the program OGGMT001 you copied from the zOSPrograms.tar file, you must change it in the JCL. The null parameters on the PROC statement are there for information purposes. The job OGGJT001 setup program supplies those values using information passed from the Extract. You may also specify as many step library dataset names as required. The JCL procedure supplied in the zOSPrograms.tar file gives an example using more than one step library.