Making changes to the QueryGrid configuration can potentially impact production workloads. QueryGrid supports the ability to test configuration changes before those changes are activated. After the configuration change is tested and verified, the changes can be activated and becomes available to production workloads.
Changes to configuration entities (fabrics, connectors, links, communication policies, and networks) are versioned. When a query starts, it resolves which versions of the configuration entities it uses. These versions are passed around to all components executing on behalf of that query, so that all components use the same version of the configuration.
When a configuration change is made, it takes time for that change to reach all the components of a system. If a query references a version of a configuration entity that has not been propagated throughout the system, the query fails. Configuration changes should be persisted and tested before being applied to production workloads to make sure the configuration change is distributed to all the components of QueryGrid.
- Active – Tested and verified actively running version of the configuration.
- Pending – Used for testing new or modified configurations.
- Previous – Active configurations put in a previous state when another version of the configuration is activated.
When replacing an active version, the active version being replaced becomes the previous version and the former previous version is deleted.
When activating a pending version, the active version being replaced becomes the previous version.
When activating a previous version, the active version being replaced becomes the previous version and any pending versions remain as pending.