EventPartitioner Channels Overview of Channel Configuration

Configuring Channels 9-9 channel 9. Optionally, override the default channel configuration by adding additional channel child elements: ■ Add a max-threads child element to specify the maximum number of threads that Oracle CEP server uses to process events for this channel. Setting this value has no effect when max-size is 0. The default value is 0. channel namepriceStreamname max-threads2size channel When set to 0, the channel acts as a pass-through. When max-threads 0, the channel acts as classic blocking queue, where upstream components are producers of events and the downstream components are the consumers of events. The queue size is defined by the configuration max-size. There will be up to max-threads number of threads consuming events from the queue. ■ Add a max-size child element to specify the maximum size of the channel. Zero-size channels synchronously pass-through events. Non-zero size channels process events asynchronously, buffering events by the requested size. The default value is 0. channel namepriceStreamname max-size10000size channel ■ Add a heartbeat child element to specify the number of nanoseconds a channel can be idle before Oracle CEP generates a heartbeat event to advance time. The heartbeat child element applies to system-timestamped relations or streams only when no events arrive in the event channels that are feeding the processors and the processor has been configured with a statement that includes some temporal operator, such as a time-based window or a pattern matching with duration. channel nameMatchOutputChannelname heartbeat10000heartbeat channel ■ Add a selector child element to specify which up-stream Oracle CQL processor queries are permitted to output their results to the channel. You may configure a channel element with a selector before creating the queries in the upstream processor. In this case, you must specify query names that match the names in the selector. For more information, Section 9.1.5, Controlling Which Queries Output to a Downstream Channel: selector . Caution: Identifiers and names in XML files are case sensitive. Be sure to specify the same case when referencing the components identifier in the EPN assembly file.