PranaviAncha commented on code in PR #3085: URL: https://github.com/apache/helix/pull/3085#discussion_r2592106410
########## website/1.4.3/src/site/markdown/tutorial_messaging.md: ########## @@ -25,6 +25,26 @@ under the License. In this chapter, we\'ll learn about messaging, a convenient feature in Helix for sending messages between nodes of a cluster. This is an interesting feature that is quite useful in practice. It is common that nodes in a distributed system require a mechanism to interact with each other. +### Performance Considerations + +**IMPORTANT:** When using the messaging API with `Criteria`, be aware of the following performance characteristics: + +- **ExternalView Scanning:** By default, the messaging service uses `DataSource.EXTERNALVIEW` to resolve criteria. This can scan **all** ExternalView znodes in the cluster, even when targeting specific instances. At high resource cardinality (thousands of resources), this can cause severe performance degradation. Review Comment: ```suggestion - **ExternalView Scanning:** By default, the messaging service uses `DataSource.EXTERNALVIEW` to resolve criteria. This can scan **all** ExternalView znodes in the cluster, even when targeting specific instances. At high resource cardinality, this can cause severe performance degradation. ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
