ragarkar commented on PR #4799: URL: https://github.com/apache/hbase/pull/4799#issuecomment-1257548111
> Mind explaining more about the algorithm here? > > I guess the problem here is that, when moving a region from rs A to rs B, the block cache on A is useless now and then on rs B, we need to reload the block cache of this region, and it will evict other regions data? > > What is the algo here to measure this cost? > > Thanks. Hello, All the region servers maintain a list of all the HFiles which are already cached. This change was done as part of HBASE-27313. The current JIRA uses this information to find out the ratio of files already cached to the total number of files in the region server and puts this information in the region specific metric. The stochastic load balancer uses this information to find out the cost of moving a region from one region server to the other by comparing the ratio of files already prefetched. Higher the ratio of files prefetched on a region server, lower the cost of moving the region. -- 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]
