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https://issues.apache.org/jira/browse/LENS-356?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14339887#comment-14339887
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Rajat Khandelwal commented on LENS-356:
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As discussed with [~himanshu.gahlaut] Lets's also keep the following use case
in mind:
Say there are two drivers, d1 and d2 in the system. The minimum estimate result
can be zero. And we are going with n-1 threads approach. Caller thread picks up
estimating for d1 and the other thread picks up d2. the other thread returns
zero pretty fast and the caller thread is still waiting for its operation to
complete. The time it waits is wasted time since it's anyway going to return
zero. On the other hand, the approach of n threads might allow us to take care
of such situations.
> Run estimate for each driver in parallel
> -----------------------------------------
>
> Key: LENS-356
> URL: https://issues.apache.org/jira/browse/LENS-356
> Project: Apache Lens
> Issue Type: Sub-task
> Components: server
> Reporter: Amareshwari Sriramadasu
> Assignee: Amareshwari Sriramadasu
> Fix For: 2.1
>
>
> We are estimating the cost of query on each driver sequentially. Since each
> estimate is independent those can be parallelized.
> For each driver rewrite the query, call driver.estimate - need to parallelize
> this for all drivers.
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