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https://issues.apache.org/jira/browse/LUCENE-2829?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12974212#action_12974212
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Yonik Seeley edited comment on LUCENE-2829 at 12/22/10 9:24 AM:
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Why not keep the TermState cache and use it for all queries except MTQ, while 
using a different mechanism for MTQ to avoid trashing the cache?

The cache has a number of advantages that may never be duplicated in a 
different type of API, including
- actually cache frequently used terms across different requests
- cache terms reused in the same request.  term proximity boosting is an 
example:   +united +states "united states"^10

edit: and as robert previously pointed out, if we cached misses as well, then 
we could avoid needless seeks on segments that don't contain the term.

      was (Author: ysee...@gmail.com):
    Why not keep the TermState cache and use it for all queries except MTQ, 
while using a different mechanism for MTQ to avoid trashing the cache?

The cache has a number of advantages that may never be duplicated in a 
different type of API, including
- actually cache frequently used terms across different requests
- cache terms reused in the same request.  term proximity boosting is an 
example:   +united +states "united states"^10
  
> improve termquery "pk lookup" performance
> -----------------------------------------
>
>                 Key: LUCENE-2829
>                 URL: https://issues.apache.org/jira/browse/LUCENE-2829
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: Search
>            Reporter: Robert Muir
>         Attachments: LUCENE-2829.patch
>
>
> For things that are like primary keys and don't exist in some segments (worst 
> case is primary/unique key that only exists in 1)
> we do wasted seeks.
> While LUCENE-2694 tries to solve some of this issue with TermState, I'm 
> concerned we could every backport that to 3.1 for example.
> This is a simpler solution here just to solve this one problem in 
> termquery... we could just revert it in trunk when we resolve LUCENE-2694,
> but I don't think we should leave things as they are in 3.x

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