gianm 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_r306039479
########## 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| +|`druid.realtime.cache.maxEntrySize`|Maximum cache entry size in bytes.|1_000_000| Review comment: What happens is "the result is not recorded in the cache; cache `*/put/oversized` metrics are incremented." The `*/put/oversized` syntax would match how they are described in metrics.md, so I think that'd be the right way to write it in user-facing docs. The `*` could be `query/cache/delta` or `query/cache/total`, also mentioned in metrics.md. ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org For additional commands, e-mail: commits-h...@druid.apache.org
