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Mark Miller commented on LUCENE-1606: ------------------------------------- {quote}on my big index its actually faster without setting the constant score rewrite (maybe creating the huge bitset is expensive?){quote} Thats surprising, because I have seen people state the opposite on a couple occasions. Perhaps it has to do with how many terms are being enumerated? > 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 > Priority: Minor > Fix For: 2.9 > > Attachments: automaton.patch, automatonMultiQuery.patch, > automatonWithWildCard.patch, automatonWithWildCard2.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. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online. --------------------------------------------------------------------- To unsubscribe, e-mail: java-dev-unsubscr...@lucene.apache.org For additional commands, e-mail: java-dev-h...@lucene.apache.org