[GitHub] [accumulo] keith-turner opened a new pull request, #3756: avoids creating server side threads when canceling failed write

["keith-turner (via GitHub)" <gi...@apache.org>]

keith-turner opened a new pull request, #3756:
URL: https://github.com/apache/accumulo/pull/3756

   This commit is a follow up to #3733. When a failure happens on a batch write, the batch writer will continually try to close the write session. Each time it tried to close the session it created a thread that may wait on the tserver trying to reserve the session which takes up a server side thrift thread pool slot.  After the 2 min default connection timeout it will try to close the session again, creating another thread on the tserver that is trying to close the session (the previous threads are still there).  This will only happen when something is preventing the the session from closing.  So in the case where many clients are doing this it has the potential to make an existing problem worse.
   
   This change introduces a new tablet server RPC named cancelUpdate. The new method does not try to reserve the session.  If the session is reserved it returns false, if not it deletes it and returns true.  The client will retry with backoff calling this new RPC until it returns true.  This new RPC will not leave threads waiting on the tserver. Since this change was made in a bug fix release, it can detect if the new RPC method does not exists and fall back to the existing closeUpdate RPC.


-- 
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: notifications-unsubscribe@accumulo.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org

[GitHub] [accumulo] keith-turner merged pull request #3756: avoids creating server side threads when canceling failed write

["keith-turner (via GitHub)" <gi...@apache.org>]

keith-turner merged PR #3756:
URL: https://github.com/apache/accumulo/pull/3756


-- 
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: notifications-unsubscribe@accumulo.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org