DC391502 and DC200175 GROUP RESTART messages at IDMS CV startup

Products

• IDMS

Issue/Introduction

At startup, a CV in a data sharing environment may issue messages similar to the following:

IDMS DC391502 V1 Group restart is necessary; coordinator is CV01
...
IDMS DC200171 V1 T1 Restart status of Data Sharing Group DSG1
IDMS DC200172 V1 T1 Group DSG1     Member CV01   is Active CV status Ready
IDMS DC200172 V1 T1 Group DSG1     Member CV02   is Failed CV status N/A
IDMS DC200172 V1 T1 Group DSG1     Member CV03   is Failed CV status N/A
IDMS DC200173 V1 T1 Waiting for group members not in the READY state.
IDMS DC200172 V1 T1 Group DSG1     Member CV02   is Active CV status Ready
IDMS DC200172 V1 T1 Group DSG1     Member CV03   is Active CV status Ready
IDMS DC200174 V1 T1 All known group members are READY.  
IDMS DC200175 V1 T1 Is the group restart complete?  Reply Y/N (D displays restart status)

This article describes the reason for these messages and the action that must be taken.

Environment

Release: All supported releases.

Cause

At startup of an IDMS CV that participates in a data sharing group, the CV queries the relevant CF structures for information about the group's member CVs. It is possible that there may be a problem with that CF structure. It could be corrupt, or could have been cleared for some reason. If that is the case, a GROUP RESTART of the data sharing group must be performed. The first member of the group that starts up after this situation with the CF has arisen will identify this condition, and become the coordinator of the group restart.

The DC200172 and DC200173 messages identify the other CVs in the group and whether or not they are ready for the group restart. When all of those members are ready, the DC200174 message will be issued. Then the DC200175 message is issued soliciting a response from the user.

Resolution

The intention of the DC200174 and DC200175 messages is to inform the user that the IDMS software is satisfied that all of the CVs that it knows about are ready for the group restart to proceed. However, depending on the nature of the problem that the CF encountered, it is possible, although rare, that there may be other CVs in the group that the coordinator does not know about and are not identified by those messages. Therefore, it is the responsibility of the user to make sure that all of the CVs in the data sharing group have been started and have advanced to the point where they have issued this message:

IDMS DC200170 V2 T1 Waiting on group restart completion.

Failure to ensure that this is the case will result in database corruption because any updates performed by any CVs that have not been started and reached DC200170 will be neither rolled out nor committed.

Once the user has confirmed that all of the member CVs of the data sharing group are ready, reply to the DC200175 message on the coordinating CV with "Y", and the group restart will proceed.