[jira] [Updated] (YARN-3367) Replace starting a separate thread for post entity with event loop in TimelineClient

["Naganarasimha G R (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/YARN-3367?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Naganarasimha G R updated YARN-3367:
------------------------------------
    Attachment: YARN-3367.YARN-2928.001.patch

Uploading an initial patch with no test case for this jira :
Some open points which needs more discussion 
# Timelineclient async calls are only to ensure the client need not wait till the server response & just return immediately after requesting to post entity or even in server side we need to ensure some thing ? As currently we are trying to send the async parameter to the server.
# According earlier discussion we had to decide whether to have 2 cross 2 matric wrt sync/async & writer flush & not flush in server side, but after YARN-4061 (Fault tolerant writer for timeline v2), i presume client need not ensure much as consistency will be handled in server side and IMO it would be sufficent to just have non blocking call for async
# Is it important to maintain the order of events which are sent from sync and async ? i.e. Is it req to ensure all the async events are also pushed along with the current sync event or is it ok to send only the sync ? (current patch just ensures async events are in order) .
# Whether its req to merge entities of multiple async calls as they belong to same application ?

Please kindly review and share your thoughts on the above points.
cc /[~sjlee0] Informing you, as you had asked to include you in discussion for these points and also you were not watching for this jira 

> Replace starting a separate thread for post entity with event loop in TimelineClient
> ------------------------------------------------------------------------------------
>
>                 Key: YARN-3367
>                 URL: https://issues.apache.org/jira/browse/YARN-3367
>             Project: Hadoop YARN
>          Issue Type: Sub-task
>          Components: timelineserver
>    Affects Versions: YARN-2928
>            Reporter: Junping Du
>            Assignee: Naganarasimha G R
>         Attachments: YARN-3367.YARN-2928.001.patch
>
>
> Since YARN-3039, we add loop in TimelineClient to wait for collectorServiceAddress ready before posting any entity. In consumer of  TimelineClient (like AM), we are starting a new thread for each call to get rid of potential deadlock in main thread. This way has at least 3 major defects:
> 1. The consumer need some additional code to wrap a thread before calling putEntities() in TimelineClient.
> 2. It cost many thread resources which is unnecessary.
> 3. The sequence of events could be out of order because each posting operation thread get out of waiting loop randomly.
> We should have something like event loop in TimelineClient side, putEntities() only put related entities into a queue of entities and a separated thread handle to deliver entities in queue to collector via REST call.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)