How mixed version cluster repositories are updated

Repositories store records for an object in a cluster in the version of the record format that matches the version of the queue manager hosting the repository. Repository queue managers forward object records, before they are stored, in the format that they are received in. The recipient ignores fields from a newer version, and uses default values for fields that are not present in the record.

Cluster repositories hold records that represent objects, for example, a queue record represents a cluster queue. A full repository holds records for all objects in the cluster. Partial repositories hold records for local objects and remote objects that are used locally. A repository record can hold information only about attributes at the same command level as the queue manager holding that repository. So for example, a Version 6.0 repository contains only Version 6.0 level attribute information. A Version 7.5 repository contains all Version 6.0 records, plus Version 7.5 records containing additional Version 7.5 attributes.

A repository stores a record it receives in its own version. If the record it receives is at a later version, the later version attributes are discarded when the record is stored. A Version 6.0 queue manager receiving information about a Version 7.5 queue manager stores only Version 6.0 information. A Version 7.5 repository receiving a version 6 record stores default values for attributes introduced in the version 7. The defaults define the values for the attributes that are not included in the record it receives.

A repository normally sends records in its own version format, which is the same as the format it has stored them in. There is one exception to this rule. When a full repository receives a record from a partial repository, it is immediately forwarded in the same format. So if a Version 6.0 full repository were to receive a record from a Version 7.5 partial repository, it would forward the Version 7.5 record. It sends the record to any other full repositories, and any other partial repositories that have subscriptions that match the record.

A partial repository reflects whichever full repository sent it the latest update to a record. As a consequence, you might see the information held by a Version 7.5 partial repository for new Version 7.5 attributes changing unexpectedly. The values might change from actual Version 7.5 information to default values. The changes occur if the full repositories in the cluster are at different levels. Migrate full repositories first to avoid instability.

A partial repository sends information about its objects to a full repository periodically at least once every 27 days. Information is sent about any object when it is altered or defined.