[jira] Issue Comment Edited: (LUCENE-1606) Automaton Query/Filter (scalable regex)

["Mark Miller (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LUCENE-1606?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12780430#action_12780430 ] 

Mark Miller edited comment on LUCENE-1606 at 11/20/09 4:46 AM:
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So Robert - what do you think about paring down the automaton lib, and shoving all this in core? I want it, I want, I want it :)

You should also post the info about that Fuzzy possibility you were mentioning - perhaps a math head will come along and take care of that for us with the proper setup.

      was (Author: markrmiller@gmail.com):
    So Robert - what do you think about paring down the automaton lib, and shoving all this in core? I want it, I want, I want it :)
  
> 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
>
>
> 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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