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https://issues.apache.org/jira/browse/YARN-4199?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Shiwei Guo resolved YARN-4199.
------------------------------
    Resolution: Duplicate

> Minimize lock time in LeveldbTimelineStore.discardOldEntities
> -------------------------------------------------------------
>
>                 Key: YARN-4199
>                 URL: https://issues.apache.org/jira/browse/YARN-4199
>             Project: Hadoop YARN
>          Issue Type: Improvement
>          Components: timelineserver, yarn
>            Reporter: Shiwei Guo
>
> In current implementation, LeveldbTimelineStore.discardOldEntities holds a 
> writeLock on deleteLock, which will block other put operation, which 
> eventually block the execution of YARN jobs(e.g. TEZ). When there is lots of 
> history jobs in timelinestore, the block time will be very long. In our 
> observation, it block all the TEZ jobs for several hours or longer. 
> The possible solutions are:
> - Optimize leveldb configuration,  so a full scan won't take long time.
> - Take a snapshot of leveldb, and scan the snapshot, so we only need to hold 
> lock while getSnapshot. One question is that whether snapshot will take long 
> time or not, cause I have no experience with leveldb.



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