9.5. Caching Considerations

Although, you can find information about all JBoss Data Virtualization settings using the Management CLI (see Section 10.1, “JBoss Data Virtualization Settings”), this section provides some additional information about those settings related to caching.

JBoss Data Virtualization settings regarding cache tuning are divided amongst:

Cache statistics can be obtained through the Management Console or AdminShell. The statistics can be used to help tune cache parameters and ensure a hit ratio.

Plans are currently fully held in memory and may have a significant memory footprint. When making extensive use of prepared statements and/or virtual procedures, the size of the plan cache may be increased proportionally to number of gigabytes intended for use by JBoss Data Virtualization.

While the result cache parameters control the cache result entries (such as max number, and eviction), the result batches themselves are accessed through the buffer manager. If the size of the result cache is increased, you may need to tune the buffer manager configuration to ensure there is enough buffer space.

Result set and prepared plan caches have their entries invalidated by data and metadata events. By default, these events are captured by running commands through JBoss Data Virtualization (see the Red Hat JBoss Data Virtualization Developer Guide for further customization). JBoss Data Virtualization stores compiled forms of update plans or trigger actions with the prepared plan so that if metadata changes, the changes may take effect immediately.

The default resultset-cache-max-staleness for resultset caching is 60 seconds to improve efficiency with rapidly changing sources. Consider decreasing this value to make the resultset cache more consistent with the underlying data. Even with a setting of 0, full transactional consistency is not guaranteed.