/CQCHKPT command

The /CQCHKPT command initiates a CQS checkpoint for a specific coupling facility list structure or all the coupling facility list structures to which the IMS™ subsystem is connected.

Subsections:

Environment
Syntax
Keywords
Usage notes
Examples

Environment

The following table lists the environments (DB/DC, DBCTL, and DCCTL) in which you can use the command and keywords.

Table 1. Valid environments for the /CQCHKPT command and keywords
Command / Keywords	DB/DC	DCCTL
/CQCHKPT	X	X
SHAREDQ	X	X
STRUCTURE	X	X
SYSTEM	X	X

Syntax


>>-+-/CQCHKPT-+--+-SYSTEM--+--STRUCTURE------------------------->
   '-/CQC-----'  '-SHAREDQ-'              

     .---------------.     
     V               |     
>--+---structurename-+-+---------------------------------------><
   '-ALL---------------'

Keywords

The following keywords are valid for the /CQCHKPT command:

SHAREDQ

Specifies that the entire queue structure is to be checkpointed to the structure recovery data set. While the checkpoint is in progress for the structure, no CQS can access the structure.

During a structure checkpoint, every CQS connected to that structure also takes a system checkpoint.

Recommendation: When possible, issue this command when it will have the least performance impact to your online IMS subsystems.

STRUCTURE

Specifies a specific structure name (or all) for which a CQS checkpoint is to be taken. If an overflow structure exists for a structure, a checkpoint is taken for both the primary and overflow structure.

SYSTEM

Specifies that a system checkpoint is to be taken; the CQS internal tables are checkpointed and written to the CQS log. Only the CQS for which you enter the command takes a system checkpoint.

Usage notes

This command sends the DFS058 CQCHKPT COMMAND IN PROGRESS message to the inputting terminal, and sends an asynchronous response to the system console and master terminal when the CQS checkpoint is complete.

This command is valid only in a shared-queues environment.

This command can be issued to an IMSplex using the Batch SPOC utility.

Examples

The following are examples of the /CQCHKPT command:

Example 1 for /CQCHKPT command

Entry ET:

  /CQCHKPT SYSTEM STRUCTURE IMSMSGQ01

Response ET:

  DFS058I CQCHKPT COMMAND IN PROGRESS
  CQS0030I SYSTEM CHECKPOINT COMPLETE, STRUCTURE IMSMSGQ01       ,
   LOGTOKEN 0000000001687D3F CQS1CQS
  DFS1972I CQCHKPT SYSTEM  COMMAND COMPLETE FOR STRUCTURE=IMSMSGQ01

Explanation: A CQS system checkpoint completes successfully.

Recommendation: Record the log token displayed in the CQS0030I message because you might need it for a CQS restart.

Example 2 for /CQCHKPT command

Entry ET:

  /CQCHKPT SHAREDQ STRUCTURE IMSMSGQ01

Response ET:

  DFS058I CQCHKPT COMMAND IN PROGRESS
  CQS0220I CQS CQS1CQS  STARTED STRUCTURE CHECKPOINT FOR
   STRUCTURE IMSMSGQ01        CQS1CQS
  CQS0200I STRUCTURE IMSMSGQ01        QUIESCED FOR
   STRUCTURE CHECKPOINT CQS1CQS
  CQS0201I STRUCTURE IMSMSGQ01        RESUMED AFTER
   STRUCTURE CHECKPOINT CQS1CQS
  CQS0030I SYSTEM CHECKPOINT COMPLETE, STRUCTURE IMSMSGQ01       ,
   LOGTOKEN 0000000001688652 CQS1CQS
  CQS0221I CQS CQS1CQS  COMPLETED STRUCTURE CHECKPOINT
   FOR STRUCTURE IMSMSGQ01        CQS1CQS
  DFS1972I CQCHKPT SHAREDQ COMMAND COMPLETE FOR STRUCTURE=IMSMSGQ01

Explanation: A CQS structure checkpoint for a specific structure completes successfully.