Apache9 commented on pull request #2095: URL: https://github.com/apache/hbase/pull/2095#issuecomment-662171539
> Seems fine if we ok w/ building a new specialized serving system on Masters with new APIs, new RPCs in MasterRPCService (only), a specialized Read Replica of a Region for the locations ColumnFamily, and so on which requires ROOT stay 'small'? New configs, new area of concern for operations. > > On the location fetch of all meta locations, could return empty if there has been no change since the last fetch? > > Any thoughts on doing the likes of this Locations map in front of hbase:meta Region Replicas -- hbase:meta will be too big to do this trick? -- or these Replicas being out on RSs rather than on Master? > > Thanks. Since we are introducing a new feature, I think it is OK to introduce new configs? The baseline should not be the system without the new feature, we should comparing with other approach. For read replicas, I think the new configs will be much more, and the operations will also be much more complicated, and much more difficult to debug the problem. Or if you are talking about other solutions, please also provide at least a workable POC? The PR here shows every details to you as it can pass all the UTs, so it is easy to say that 'you introduce new configs so I do not like it, it adds new concerns'. Please try other solutions to see how many configs do you need to support them. And on the future, I do have a plan. The plan is to use raft to make HA masters. The design is to store the root table on HMaster locally, even do not on HDFS. User could still use the same APIs to get the content of root, no big impact to users behaviors if they use MasterRegistry, which will be the default registry for 3.0+. And by using raft, the latency of syncing the content of root table from leader to follower(learner) will be much lesser(even comparing to read replicas) as the leader will fan out the modifications to all other nodes in the system. And also, it could store large root table as well, at least, several GBs is still fine. Thanks. ---------------------------------------------------------------- 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
