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https://issues.apache.org/jira/browse/SOLR-12833?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16708910#comment-16708910
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Mark Miller commented on SOLR-12833:
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Hey [~yuanyun.cn], how does this approach look to you?
It keeps the api more like the good practice use of a tryLock pattern.
We can also just make a timeout the main path - those that want to mimic
unlimited can set it to max int - so I don't know that we need as much
additional testing - by pretty much just passing on calls to the underlying
lock, we can count on that working as advertised.
> Use timed-out lock in DistributedUpdateProcessor
> ------------------------------------------------
>
> Key: SOLR-12833
> URL: https://issues.apache.org/jira/browse/SOLR-12833
> Project: Solr
> Issue Type: Improvement
> Security Level: Public(Default Security Level. Issues are Public)
> Components: update, UpdateRequestProcessors
> Affects Versions: 7.5, master (8.0)
> Reporter: jefferyyuan
> Assignee: Mark Miller
> Priority: Minor
> Fix For: master (8.0)
>
> Attachments: SOLR-12833.patch
>
>
> There is a synchronize block that blocks other update requests whose IDs fall
> in the same hash bucket. The update waits forever until it gets the lock at
> the synchronize block, this can be a problem in some cases.
>
> Some add/update requests (for example updates with spatial/shape analysis)
> like may take time (30+ seconds or even more), this would the request time
> out and fail.
> Client may retry the same requests multiple times or several minutes, this
> would make things worse.
> The server side receives all the update requests but all except one can do
> nothing, have to wait there. This wastes precious memory and cpu resource.
> We have seen the case 2000+ threads are blocking at the synchronize lock, and
> only a few updates are making progress. Each thread takes 3+ mb memory which
> causes OOM.
> Also if the update can't get the lock in expected time range, its better to
> fail fast.
>
> We can have one configuration in solrconfig.xml:
> updateHandler/versionLock/timeInMill, so users can specify how long they want
> to wait the version bucket lock.
> The default value can be -1, so it behaves same - wait forever until it gets
> the lock.
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