Configuring conflation
Use the CONFLATION topic property to select a conflation policy for a topic.
Conflation settings
Conflation is configured through several settings.
Conflation can be enabled or disabled on a per session basis using the setConflated API call. The default value for this is set using the conflates value in the queue-definition section of Server.xml. In Diffusion™ 6.1, this is set to true for a fresh installation.
You can specify the conflation policy for each topic when it is created, using the CONFLATION topic property. The default policy is "conflate" (see below).
As a result, for non-deprecated topics, the "conflate" policy will be applied by default.
Conflation policies
Use the CONFLATION topic property to set a topic's conflation policy using one of the following values.
| Property | Description |
|---|---|
| conflate (default) | Only conflate topics when a session with a full queue receives a new message. |
| always | An 'eager' policy that conflates updates as they arrive. If enabled, the queue will only ever contain one update. |
| off | Disable conflation for this topic. Sessions receive every update. |
| unsubscribe | When a session with a full queue receives a new message, unsubscribe the session with unsubscribe reason BACK_PRESSURE. |
For the deprecated single value, record and stateless topic types, if you set "always" or "conflate", the legacy conflation system described in Configuring legacy conflation is applied instead. If you set "off", the legacy conflation system will not be used. If you set "unsubscribe", the legacy conflation system will be used, and the "unsubscribe" policy will be applied when a session with a full queue receives a new message.
This page last modified: 2018/04/23