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https://issues.apache.org/jira/browse/SOLR-5986?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14062187#comment-14062187
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Steve Davids commented on SOLR-5986:
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In an ideal world it would attempt to provide results for the shards that may
be okay, but the end goal is to maintain the health of the cluster for queries
that get out of hand. If you can know up front that there is no possible way
that a query could complete then it would be reasonable to error out
immediately (though that metric may be squishy to know if it will/will not
complete). Hopefully that makes sense...
> Don't allow runaway queries from harming Solr cluster health or search
> performance
> ----------------------------------------------------------------------------------
>
> Key: SOLR-5986
> URL: https://issues.apache.org/jira/browse/SOLR-5986
> Project: Solr
> Issue Type: Improvement
> Components: search
> Reporter: Steve Davids
> Priority: Critical
> Fix For: 4.9
>
>
> The intent of this ticket is to have all distributed search requests stop
> wasting CPU cycles on requests that have already timed out or are so
> complicated that they won't be able to execute. We have come across a case
> where a nasty wildcard query within a proximity clause was causing the
> cluster to enumerate terms for hours even though the query timeout was set to
> minutes. This caused a noticeable slowdown within the system which made us
> restart the replicas that happened to service that one request, the worst
> case scenario are users with a relatively low zk timeout value will have
> nodes start dropping from the cluster due to long GC pauses.
> [~amccurry] Built a mechanism into Apache Blur to help with the issue in
> BLUR-142 (see commit comment for code, though look at the latest code on the
> trunk for newer bug fixes).
> Solr should be able to either prevent these problematic queries from running
> by some heuristic (possibly estimated size of heap usage) or be able to
> execute a thread interrupt on all query threads once the time threshold is
> met. This issue mirrors what others have discussed on the mailing list:
> http://mail-archives.apache.org/mod_mbox/lucene-solr-user/200903.mbox/%[email protected]%3E
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