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https://issues.apache.org/jira/browse/LUCENE-8027?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16953520#comment-16953520
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yunfeng commented on LUCENE-8027:
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[~atris] If sub-query all took long times to cache, but the cost just not
satisfy the criterion? sub-query A took 50ms and sub-query B took 50ms, in
this situation how we can do ? Cache sub-query may accelerate other compound
query using this sub-query, if we do not cache the sub-query and just cache the
top-level query, Does this have problem?
> Do not cache clauses if they might make the query more than X times slower
> --------------------------------------------------------------------------
>
> Key: LUCENE-8027
> URL: https://issues.apache.org/jira/browse/LUCENE-8027
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Adrien Grand
> Priority: Minor
> Attachments: LUCENE-8027.patch
>
>
> Query caching can have a negative impact on tail latencies as the clause that
> is cached needs to be entirely consumed. Maybe we could leverage the fact
> that we can know the lead cost from any scorer now (LUCENE-7897) in order to
> implement heuristics that would look like "do not cache clause X if its cost
> is 10x greater than the cost of the entire query". This would make sure that
> a fast query can not become absurdly slow just because it had to cache a
> costly filter. The filter will need to wait for a more costly query to be
> cached, or might never be cached at all.
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