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Michael McCandless commented on LUCENE-1593: -------------------------------------------- bq. Change TSDC and TFC's code to not use the doc id as a tie breaker. We have to remember that out-of-order docID collectors (BooleanScorer) cannot apply this optimization. When we get to this, lets make sure we have a test case that does out-of-order collection, with a field search, that shows failure if we fail to break ties by docID. Actually, the optimization can be applied sometimes: if we can push bottomVal testing down to each TermDocs enum (much like unfactoring random-access filter down to the TermDocs), that first pass collection in BooleanScorer is in fact in order. But that's a deeper optimization... > Optimizations to TopScoreDocCollector and TopFieldCollector > ----------------------------------------------------------- > > Key: LUCENE-1593 > URL: https://issues.apache.org/jira/browse/LUCENE-1593 > Project: Lucene - Java > Issue Type: Improvement > Components: Search > Reporter: Shai Erera > Fix For: 2.9 > > > This is a spin-off of LUCENE-1575 and proposes to optimize TSDC and TFC code > to remove unnecessary checks. The plan is: > # Ensure that IndexSearcher returns segements in increasing doc Id order, > instead of numDocs(). > # Change TSDC and TFC's code to not use the doc id as a tie breaker. New docs > will always have larger ids and therefore cannot compete. > # Pre-populate HitQueue with sentinel values in TSDC (score = Float.NEG_INF) > and remove the check if reusableSD == null. > # Also move to use "changing top" and then call adjustTop(), in case we > update the queue. > # some methods in Sort explicitly add SortField.FIELD_DOC as a "tie breaker" > for the last SortField. But, doing so should not be necessary (since we > already break ties by docID), and is in fact less efficient (once the above > optimization is in). > # Investigate PQ - can we deprecate insert() and have only > insertWithOverflow()? Add a addDummyObjects method which will populate the > queue without "arranging" it, just store the objects in the array (this can > be used to pre-populate sentinel values)? > I will post a patch as well as some perf measurements as soon as I have them. -- 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