I suspect this could only show up as a bottleneck if they run very cheap queries (low cost) at a very high throughput? Is it the case? I've seen a couple workloads like that in the past and profilers suggested that things that usually do not matter were bottleneck like creating scorers or deciding whether a query should be cached. But trying to fix it didn't really help as there are lots of things that we need to do to decide how to run a query that run in O(num_segments * num_clauses)
I'm confused why MinShouldMatchSumScorer would be used when minShouldMatch is 0 or 1. DisjunctionSumScorer should be used instead for such values of minShouldMatch? Le jeu. 7 juin 2018 à 19:38, Michael McCandless <luc...@mikemccandless.com> a écrit : > Doesn't BQ rewrite itself if it has only one clause? > > Or maybe if there were more than one clause, and then all but one of them > had null scorers (on SHOULD clauses) you could wind up in that state? > > Mike McCandless > > http://blog.mikemccandless.com > > On Thu, Jun 7, 2018 at 1:21 PM, David Smiley <david.w.smi...@gmail.com> > wrote: > >> I'm working with some folks who did some profiling and noticed that >> ScorerSupplier.cost() can be expensive (as the javadocs say). cost() says >> only to call it if necessary. Unfortunately, a BooleanQuery is going to >> call cost() (via BooleanWeight.scorer() even if ultimately no Query in the >> tree cares what the cost is. I'm not sure if that's a perf bug or not; >> it's hard to tell. >> >> The expensive part of cost() for Boolean2ScorerSupplier is over in >> MinShouldMatchSumScorer.cost which creates a PriorityQueue every time, even >> if trivially numScorers == 1. That's a weird case... why do we even need a >> Boolean2ScorerSupplier around one clause; couldn't that clause be returned >> from the outer weight, BooleanWeight.scorerSupplier() close to the end as >> an optimization? I could file an issue. >> >> ~ David >> -- >> Lucene/Solr Search Committer, Consultant, Developer, Author, Speaker >> LinkedIn: http://linkedin.com/in/davidwsmiley | Book: >> http://www.solrenterprisesearchserver.com >> > >
