[
https://issues.apache.org/jira/browse/HADOOP-16268?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16909366#comment-16909366
]
CR Hota commented on HADOOP-16268:
----------------------------------
[~xkrogen] Thanks for the review. Below is a little explanation of the change.
The idea here is to back off even if {{FairCallQueue}} is not configured
(FairCallQueue in the context of router doesn't help much, as fairness in
routers has a separate context as mentioned in HDFS-14090). So irrespective of
actual queue implementation, if a queue is full call manager should throw
{{StandbyException}} instead {{RetriableException}}. In case {{FairCallQueue}}
is not enabled, the default {{LinkedBlockingQueue}} is used, which will throw
an {{IllegalStateException}} when full and this exception also gets handled by
{{throwBackoff}} logic. Let me know your thoughts.
[~jojochuang] [~elgoiri] [~brahmareddy] FYI ..
> Allow custom wrapped exception to be thrown by server if RPC call queue is
> filled up
> ------------------------------------------------------------------------------------
>
> Key: HADOOP-16268
> URL: https://issues.apache.org/jira/browse/HADOOP-16268
> Project: Hadoop Common
> Issue Type: Improvement
> Reporter: CR Hota
> Assignee: CR Hota
> Priority: Major
> Attachments: HADOOP-16268.001.patch
>
>
> In the current implementation of callqueue manager,
> "CallQueueOverflowException" exceptions are always wrapping
> "RetriableException". Through configs servers should be allowed to throw
> custom exceptions based on new use cases.
> In CallQueueManager.java for backoff the below is done
> {code:java}
> // ideally this behavior should be controllable too.
> private void throwBackoff() throws IllegalStateException {
> throw CallQueueOverflowException.DISCONNECT;
> }
> {code}
> Since CallQueueOverflowException only wraps RetriableException clients would
> end up hitting the same server for retries. In use cases that router supports
> these overflowed requests could be handled by another router that shares the
> same state thus distributing load across a cluster of routers better. In the
> absence of any custom exception, current behavior should be supported.
> In CallQueueOverflowException class a new Standby exception wrap should be
> created. Something like the below
> {code:java}
> static final CallQueueOverflowException KEEPALIVE =
> new CallQueueOverflowException(
> new RetriableException(TOO_BUSY),
> RpcStatusProto.ERROR);
> static final CallQueueOverflowException DISCONNECT =
> new CallQueueOverflowException(
> new RetriableException(TOO_BUSY + " - disconnecting"),
> RpcStatusProto.FATAL);
> static final CallQueueOverflowException DISCONNECT2 =
> new CallQueueOverflowException(
> new StandbyException(TOO_BUSY + " - disconnecting"),
> RpcStatusProto.FATAL);
> {code}
>
--
This message was sent by Atlassian JIRA
(v7.6.14#76016)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
