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https://issues.apache.org/jira/browse/LUCENE-7526?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15628861#comment-15628861
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ASF GitHub Bot commented on LUCENE-7526:
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Github user dsmiley commented on the issue:
https://github.com/apache/lucene-solr/pull/105
_(I wrote this as you made your last comments, but rather than delete it
I'll comment any way)_
The documentation for `PostingsEnum.nextPosition()` states that calling it
more than `freq()` times is undefined. Thus it's quite valid to throw an
IllegalStateException.
> Btw, we've seen other needs for something like a CompositePostingsEnum
that abstracts over a set of terms, but since this is still internal, dropping
the house-keeping will also make this code do less.
I don't think I quite get what you're saying. By "other needs" do you mean
Bloomberg internally? If so, how would that relate this this one inside the
UH? Are you advocating a general purpose Multi-PosrtingsEnum? On the
latter... a highlighter wouldn't be where to introduce such a thing. There is
a `org.apache.lucene.index.MultiPostingsEnum` which I looked at while at the
Lucene hackday code sprint as it got my curiosity. Unfortunately, it doesn't
seem quite general purpose enough for us to use -- it demands a MultiTermsEnum
parent. Perhaps that could be improved to be useful without demanding a
MultiTermsEnum parent... but that seems like a separate issue.
> Improvements to UnifiedHighlighter OffsetStrategies
> ---------------------------------------------------
>
> Key: LUCENE-7526
> URL: https://issues.apache.org/jira/browse/LUCENE-7526
> Project: Lucene - Core
> Issue Type: Improvement
> Components: modules/highlighter
> Reporter: Timothy M. Rodriguez
> Assignee: David Smiley
> Priority: Minor
> Fix For: 6.4
>
>
> This ticket improves several of the UnifiedHighlighter FieldOffsetStrategies
> by reducing reliance on creating or re-creating TokenStreams.
> The primary changes are as follows:
> * AnalysisOffsetStrategy - split into two offset strategies
> ** MemoryIndexOffsetStrategy - the primary analysis mode that utilizes a
> MemoryIndex for producing Offsets
> ** TokenStreamOffsetStrategy - an offset strategy that avoids creating a
> MemoryIndex. Can only be used if the query distills down to terms and
> automata.
> * TokenStream removal
> ** MemoryIndexOffsetStrategy - previously a TokenStream was created to fill
> the memory index and then once consumed a new one was generated by
> uninverting the MemoryIndex back into a TokenStream if there were automata
> (wildcard/mtq queries) involved. Now this is avoided, which should save
> memory and avoid a second pass over the data.
> ** TermVectorOffsetStrategy - this was refactored in a similar way to avoid
> generating a TokenStream if automata are involved.
> ** PostingsWithTermVectorsOffsetStrategy - similar refactoring
> * CompositePostingsEnum - aggregates several underlying PostingsEnums for
> wildcard/mtq queries. This should improve relevancy by providing unified
> metrics for a wildcard across all it's term matches
> * Added a HighlightFlag for enabling the newly separated
> TokenStreamOffsetStrategy since it can adversely affect passage relevancy
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