| commit | d1995a5b76f10b94edc4bf729ace583d228e9ffa | [log] [tgz] |
|---|---|---|
| author | Adam Kocoloski <adam@cloudant.com> | Tue Apr 16 10:12:58 2013 -0400 |
| committer | Robert Newson <rnewson@apache.org> | Wed Jul 23 17:57:21 2014 +0100 |
| tree | 8e4c3b021585dad2c10fb13bb327a5adb724ee2f | |
| parent | ad795911100283df6740647492373b3377fc27bf [diff] |
Start per-node servers regardless of feature flag Previously rexi_server_mon would fail to start per-node servers on a node where the use of those servers in rexi:cast messages was disabled by the "server_per_node" feature flag. This mostly defeats the purpose of the feature flag, which is to ensure that we can start all the per-node servers before we try to use them. Moreover, it cluttered up the error logs because rexi_server_mon would crash after trying to execute a `start_child` on rexi_server. The fix is not DRY but it does the job well. BugzID: 18970
Rexi is a tailor-made RPC server application for sending CouchDB operations to nodes in a cluster. It is used in BigCouch as the remote procedure vehicle to get fabric functions to execute on remote cluster nodes.
Rexi better fits the needs of the BigCouch distributed data store by dropping some unneeded overhead in rex, the RPC server that ships with Erlang/OTP. Rexi is optimized for the case when you need to spawn a bunch of remote processes. Cast messages are sent from the origin to the remote rexi server, and local processes are spawned from there, which is vastly more efficient than spawning remote processes from the origin. You still get monitoring of the remote processes, but the request-handling process doesn't get stuck trying to connect to an overloaded/dead node. ‘rexi_DOWN’ messages will arrive at the client eventually. This has been an extremely advantageous mix of latency and failure detection, vastly improving the performance of BigCouch.
Rexi is used in conjunction with ‘Fabric’ which is also an application within BigCouch, but can be used on a stand-alone basis.
Rexi requires R13B03 or higher and can be built with rebar, which comes bundled in the repository.