wjhypo commented on pull request #11307: URL: https://github.com/apache/druid/pull/11307#issuecomment-853323924
> What's the motivation that an extra parameter `useInMemoryBitmapInQuery` is needed in query context ? I mean, if `enableInMemoryBitmap` is turned on, what is the case that `useInMemoryBitmapInQuery` should be `false` ? Hi Frank, good point. Once the feature is launched in production, I don't think we need to set `useInMemoryBitmapInQuery` to `false` again. The two knobs setting are more or less the remnant during our development to separate turning on writes and reads of this feature to be cautious. We first turned on the writes with the feature to monitor issues including task memory etc., then we found the system was stable and turned on reads with this feature to monitor potential query issues and the query performance and in case we found any issue, we would just update the query context which is faster than updating the supervisor spec in some way. On the other hand, assuming every user of this feature will verify this feature first in a dev cluster, we can also remove `useInMemoryBitmapInQuery` and leave just `enableInMemoryBitmap`, in which case even if we want to flip back to old behavior we can just update the supervisor spec again to set `enableInMemoryBitmap` to false, which is not mu ch slower than using the query context and simpler than having two confusing knobs now. I can leave `enableInMemoryBitmap` if that's more desirable? -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
