Is it my imagination or has this exact email been on the list already? Dennis Gearon
Signature Warning ---------------- It is always a good idea to learn from your own mistakes. It is usually a better idea to learn from others’ mistakes, so you do not have to make them yourself. from 'http://blogs.techrepublic.com.com/security/?p=4501&tag=nl.e036' EARTH has a Right To Life, otherwise we all die. ________________________________ From: Chris Hostetter <hossman_luc...@fucit.org> To: solr-user@lucene.apache.org Cc: yo...@lucidimagination.com Sent: Wed, February 16, 2011 6:20:28 PM Subject: Re: Searching for negative numbers very slow : This was my first thought but -1 is relatively common but we have other : numbers just as common. i assume that when you say that you mean "...we have other numbers (that are not negative) just as common, (but searching for them is much faster)" ? I don't have any insight into why your negative numbers are slower, but FWIW... : Interestingly enough : : fq=uid:-1 : fq=foo:bar : fq=alpha:omega : : is much (4x) slower than : : q="uid:-1 AND foo:bar AND alpha:omega" ...this is (in and of itself) not that suprising for any three arbitrary disjoint queries. when a BoleanQuery is a full disjunction like this (all clause required) it can efficiently skip scoring a lot of documents by looping over the clauses, asking each one for the "next" doc they match, and then leap frogging the other clauses to that doc. in the case of the three "fq" params, each query is executd in isolatin, and *all* of the matches of each is accounted for. the speed of using distinct "fq" params in situations like this comes from the reuse after they are in the filterCache -- you can change fq=foo:bar to fq=foo:baz on the next query, and still reuse 2/3 of the work that was done on the first query. likewise if hte next query is fq=uid:-1&fq=foo:bar&fq=alpha:omegabeta then 2/3 of the work is already done again, and if a following query is fq=uid:-1&fq=foo:baz&fq=alpha:omegabeta then all of the work is already done and cached even though that particular request has never been seen by solr. -Hoss
