leventov commented on a change in pull request #8116: remove unnecessary lock in ForegroundCachePopulator leading to a lot of contention URL: https://github.com/apache/incubator-druid/pull/8116#discussion_r305970857
########## File path: docs/content/configuration/index.md ########## @@ -1176,6 +1176,8 @@ You can optionally configure caching to be enabled on the peons by setting cachi |`druid.realtime.cache.useCache`|true, false|Enable the cache on the realtime.|false| |`druid.realtime.cache.populateCache`|true, false|Populate the cache on the realtime.|false| |`druid.realtime.cache.unCacheable`|All druid query types|All query types to not cache.|`["groupBy", "select"]`| +|`druid.realtime.cache.numBackgroundThreads`|If greater than 0, cache will be populated in the background thread pool of the configured size. By default cache is populated in the foreground, which can more efficiently handle reaching `maxEntrySize` than when done in the background. Note that there is no load shedding for background cache population, so it can also lead to out of memory scenarios depending on background threadpool utilization.|0| Review comment: What does it mean for cache "to be populated in the background" and "to be populated in the foreground"? Could you please add a new doc page explaining these concepts and refer to it from all these configuration parameter descriptions? ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
