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https://issues.apache.org/jira/browse/LUCENE-3225?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13053675#comment-13053675
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Simon Willnauer commented on LUCENE-3225:
-----------------------------------------
Mike this seems like a good improvement but I think letting a user change the
behavior of method X by passing true / false to method Y is no good. I think
this is kind of error prone plus its cluttering the seek method though. Once
Boolean is enough here. I think we should rather restrict this to allow users
to pull an exactMatchOnly TermsEnum which does only support exact matches and
throws a clear exception if next is called. I know that makes things slightly
harder especially to deal with our ThreadLocal cached TermsEnum instances but I
think that is better here. Can we somehow leave the extra CPU work to the
term() call and make this entirely lazy?
> Optimize TermsEnum.seek when caller doesn't need next term
> ----------------------------------------------------------
>
> Key: LUCENE-3225
> URL: https://issues.apache.org/jira/browse/LUCENE-3225
> Project: Lucene - Java
> Issue Type: Improvement
> Reporter: Michael McCandless
> Assignee: Michael McCandless
> Fix For: 4.0
>
> Attachments: LUCENE-3225.patch
>
>
> Some codecs are able to save CPU if the caller is only interested in
> exact matches. EG, Memory codec and SimpleText can do more efficient
> FSTEnum lookup if they know the caller doesn't need to know the term
> following the seek term.
> We have cases like this in Lucene, eg when IW deletes documents by
> Term, if the term is not found in a given segment then it doesn't need
> to know the ceiling term. Likewise when TermQuery looks up the term
> in each segment.
> I had done this change as part of LUCENE-3030, which is a new terms
> index that's able to save seeking for exact-only lookups, but now that
> we have Memory codec that can also save CPU I think we should commit
> this today.
> The change adds a "boolean onlyExact" param to seek(BytesRef).
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