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Uwe Schindler commented on LUCENE-1606: --------------------------------------- Yes, it should be normally be left to the user. And the slower filter on large indexes with only sparingly filled bitsets is related to LUCENE-1536. E.g. I did some comparisions for TrieRangeQuery on a 5 mio doc index, integer field, 8 bit precision step (so about 400 terms per query), the filter is about double as fast. But the ranges were random and hit about 1/3 of all documents in average per query, so the bitset is not so sparse. TrieRangeQuery is a typical example of a MultiTermQuery, that also works well with Boolean rewrite, because the upper term count is limited by the precision step (for ints and 8 bit the theoretical, but never reached, maximum is about 1700 terms, for lower precisionSteps even less). > 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