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Michael McCandless commented on LUCENE-2362: -------------------------------------------- I think in general Lucene should do a better job managing whether the filter is cheap or expensive, random access or not (LUCENE-1536), and tune the matching/scoring appropriately. But one issue with this patch: how is scoring done? It looks like in first pass you gather bit set, then you filter it w/ batch filter, then you iterate again in 2nd pass to collect the docs. But that 2nd pass won't in general have enough info to do scoring? > Add support for slow filters with batch processing > -------------------------------------------------- > > Key: LUCENE-2362 > URL: https://issues.apache.org/jira/browse/LUCENE-2362 > Project: Lucene - Java > Issue Type: Improvement > Components: Search > Affects Versions: 3.0.1 > Reporter: Sergey Vladimirov > Attachments: BatchFilter.java, IndexSearcherImpl.java > > > Internal implementation of IndexSearch assumes that Filter and scorer has > almost equal perfomance. But in our environment we have Filter implementation > that is very expensive (in compare to scorer). > if we have, let's say, 2k of termdocs selected by scorer (each ~250 docs) and > 2k selected by filter, then 250k docs will be fastly checked (and filtered > out) by scorer, and 250k docs will be slowly checked by our filter. > Using straigthforward implementation makes search out of 60 seconds per query > boundary, because each next() or advance() requires N queries to database PER > CHECKED DOC. Using read ahead technique allows us to optimze it to 35 seconds > per query. Still too slow. > The solution to problem is firstly select all documents by scorer and filter > them in batch by our filter. Example of implementation (with BitSet) in > attachement. Currently it takes only ~300 millseconds per query. -- 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