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https://issues.apache.org/jira/browse/LUCENE-1606?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12780633#action_12780633
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Robert Muir commented on LUCENE-1606:
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bq. Yes - I think so - but how to handle the fact that you fall back to it? We
might either rename it or incorporate it into the new WildcardQuery?
We could just remove the .rewrite(). it is only that very special case, for
leading *, where the existing WildcardQuery logic is slightly faster (< 5%).
I was actually surprised the wildcardquery logic beats a DFA, i guess something
to be said for that hairy logic :)
bq. Shouldn't this one eventually make the old obsolete? I say we name it
RegexQuery.
I do not know, all regex is not created equal. This one has different syntax
and stuff from the other impl's.
Any other ideas? Obviously the name RegexpQuery, with a p, is available
bq. Yup - I think we should reformat and drop the author tags. We can mention
that type of info in the NOTICE file.
ok, this is easy, i already have NOTICE in the patch. i was sure all files from
brics have their license header also.
bq. I think so - perhaps util.brics? No need for dk I don't think.
o.a.l.util.brics?
> Automaton Query/Filter (scalable regex)
> ---------------------------------------
>
> Key: LUCENE-1606
> URL: https://issues.apache.org/jira/browse/LUCENE-1606
> Project: Lucene - Java
> Issue Type: New Feature
> Components: contrib/*
> Reporter: Robert Muir
> Assignee: Robert Muir
> Priority: Minor
> Fix For: 3.1
>
> Attachments: automaton.patch, automatonMultiQuery.patch,
> automatonmultiqueryfuzzy.patch, automatonMultiQuerySmart.patch,
> automatonWithWildCard.patch, automatonWithWildCard2.patch, LUCENE-1606.patch,
> LUCENE-1606.patch, LUCENE-1606_nodep.patch
>
>
> Attached is a patch for an AutomatonQuery/Filter (name can change if its not
> suitable).
> Whereas the out-of-box contrib RegexQuery is nice, I have some very large
> indexes (100M+ unique tokens) where queries are quite slow, 2 minutes, etc.
> Additionally all of the existing RegexQuery implementations in Lucene are
> really slow if there is no constant prefix. This implementation does not
> depend upon constant prefix, and runs the same query in 640ms.
> Some use cases I envision:
> 1. lexicography/etc on large text corpora
> 2. looking for things such as urls where the prefix is not constant (http://
> or ftp://)
> The Filter uses the BRICS package (http://www.brics.dk/automaton/) to convert
> regular expressions into a DFA. Then, the filter "enumerates" terms in a
> special way, by using the underlying state machine. Here is my short
> description from the comments:
> The algorithm here is pretty basic. Enumerate terms but instead of a
> binary accept/reject do:
>
> 1. Look at the portion that is OK (did not enter a reject state in the
> DFA)
> 2. Generate the next possible String and seek to that.
> the Query simply wraps the filter with ConstantScoreQuery.
> I did not include the automaton.jar inside the patch but it can be downloaded
> from http://www.brics.dk/automaton/ and is BSD-licensed.
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