kfaraz commented on code in PR #14964: URL: https://github.com/apache/druid/pull/14964#discussion_r1322332391
########## docs/operations/basic-cluster-tuning.md: ########## @@ -90,7 +90,7 @@ Tuning the cluster so that each Historical can accept 50 queries and 10 non-quer #### Segment Cache Size -For better query performance, do not allocate segment data to a Historical in excess of the system free memory. When `free system memory` is greater than or equal to `druid.segmentCache.locations`, the more segment data the Historical can be held in the memory-mapped segment cache. +For better query performance, do not allocate segment data to a Historical in excess of the system free memory. When `free system memory` is greater than or equal to `druid.segmentCache.locations`, the Historical's memory-mapped segment cache can be held in memory, rather than being paged to disk. Review Comment: I think the new wording is a little misleading. Memory-mapping happens even if free system memory is less, but not all segments would be memory mapped. [This section](https://druid.apache.org/docs/latest/design/historical/#loading-and-serving-segments-from-cache) has a clearer explanation of the segment cache. We can reuse it. -- 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]
