On behalf of Chunhui, I am requesting review for HBASE-7403 Online Merge.
This JIRA was created 3 months ago.
Chunhui has responded to review comments very promptly, including a major
rewrite around the time split transaction was rewritten.
This feature has widely been requested. I feel the patch is mostly ready to
Here is brief recap of the steps.
Process of merging two regions:
a.client sends RPC (dispatch merging regions) to master
b.master moves the regions together (on the regionserver where the more
heavily loaded region resided)
c.master sends RPC (merge regions) to this regionserver
d.Regionserver executes the region merge transaction in the thread pool
I think step b is a nice simplification for the problem. In previous
versions of the patch, the two merging regions stay on respective servers
which required more complex coordination through zookeeper.
High level comment as well as detailed review are both welcome.