MODIFY irlmproc,DIAG command (z/OS IRLM)

The MODIFY irlmproc, DIAG command initiates diagnostic dumps for IRLM subsystems.)

If IRLM detects a delay in the child-lock propagation process, it retries the XES calls in order to recover. Use the MODIFY irlmproc , DIAG command under the direction of IBM® Software Support if this situation occurs.

Abbreviation: F

Environment

This command can be issued only from a z/OS® console.

Data sharing scope: Group

Authorization

The command requires an appropriate level of operating system authority.

Syntax

Read syntax diagramSkip visual syntax diagramMODIFYirlmproc,DIAG,DELAY,PLOCK,ALL,NONE,HANG

Option descriptions

Parameters must be separated by commas, with no spaces.
irlmproc
Specifies the procedure name of the IRLM instance that is to be diagnosed.
DIAG
Specifies that this is a diagnostic dump.
DELAY
Directs IRLM to generate a dump the first time it detects that child lock propagation to the coupling facility is taking longer than 45 seconds. The dump is placed in the SYS1.DUMPxx data set.
PLOCK
Directs IRLM to generate a dump the first time it detects that P-lock negotiation is taking longer than four minutes. Dumps of the IRLM and Db2 address spaces are placed in the SYS1.DUMPxx data set.
ALL
Directs IRLM to generate diagnostic dumps for IRLM or DBMS subsystems in a data sharing group for the following unusual conditions:
  • P-lock negotiation takes longer than four minutes.
  • Child-lock propagation takes longer than 72 seconds. IRLM retries the child lock propagation after 78 seconds if this condition still exists.
  • If IRLM detects a delay in the child-lock propagation process, it retries the XES calls in order to recover.
NONE
Disables generating all diagnostic dumps.
HANG
Collects IRLM SYSPLEX dumps when DEADLOCK or TIMEOUT issues are suspected. The dumps are taken during DEADLOCK processing. The DEADLOCK processing is stopped, and the dynamic deadlock storage is collected. z/OS DUMP services then schedules an SRB to restart DEADLOCK processing. Message DXR183I is issued by each IRLM as DEADLOCK processing is restarted. If message DXR183I is not issued by an IRLM, that IRLM must be terminated and restarted. You must start the IRLM XCF CTRACE internally and wait 30 seconds before issuing this command.

Usage notes

When to use the MODIFY irlmproc,DIAG command

The MODIFY irlmproc,DIAG command should be used only under the direction of IBM Support.

This command is active for only one incident per IRLM, that is, after an IRLM instance detects the delay and initiates the dump. You can initiate one dump per IRLM in the group. You must enter the command again to initiate another dump. Be aware that when you enter this command for one member of the data sharing group, any member that detects the delay initiates a dump.

The irlmproc identifies the procedure name for IRLM. If multiple IRLM instances exist in the same system, each procedure must have a unique name.

Trace information for data sharing members
When this command with group scope is issued in a Db2 data sharing member, it also runs on all other active members. IFICID 090 trace records for other group members can show that the same command was issued by the SYSOPR authorization ID from the 016.TLPKN5F correlation ID, in addition to the trace records from the member where the original command was issued. See Command scope in Db2 data sharing.

Example

Issue this command to initiate one diagnostic dump for the IR21PROC IRLM subsystem. The dump occurs once, after the propagation of child locks takes longer than 45 seconds. 
MODIFY IR21PROC,DIAG,DELAY