I think you are correct -- deinitely looks like a bug to me...
https://issues.apache.org/jira/browse/LUCENE-5790
: Date: Fri, 13 Jun 2014 10:45:12 +0000
: From: 海老澤 志信 <shinobu_ebis...@waku-2.com>
: Reply-To: solr-user@lucene.apache.org
: To: "solr-user@lucene.apache.org" <solr-user@lucene.apache.org>
: Subject: group.ngroups is set to an incorrect value - specific field types
:
: Hi,
:
: I'm using Solr version 4.1.
: I found a bug in group.ngroups. So could anyone kindly take a look at my bug
report?
:
: If I specify the type Double as group.field, the value of group.ngroups is
set to be an incorrect value.
:
: [condition]
: - Double is defined in group.field
: - Documents without the field which is defined as group.field,
:
: [Sample query and Example]
: -------------------------------
: solr/select?q=*:*&group=true&group.ngroups=true&group.field=Double_Field
:
: * "Double_Field" is defined "solr.TrieDoubleField" type.
: -------------------------------
: When documents with group.field are 4 and documents without group.field are 6,
: then it turns out 10 of group.ngroups as result of the query.
:
: But I think that group.ngroups should be 5 rightly in this case.
:
: [Root Cause]
: It seems there is a bug in the source code of Lucene.
: There is a function that compares a list of whether these groups contain the
same group.field,
: It calls MutableValueDouble.compareSameType().
:
: See below the point which seems to be a root cause.
: -----------------------------
: if (!exists) return -1;
: if (!b.exists) return 1;
: -----------------------------
: If "exists" is false, it return -1.
:
: But I think it should return 0, when "exists" and "b.exists" are equal.
:
: [Similar problem]
: There is a similar problem to MutableValueBool.compareSameType().
: Therefore, when you grouping the field of type Boolean (solr.BoolField),
: value of group.ngroups is always 0 or 1 .
:
: [Solution]
: I propose the following modifications: MutableValueDouble.compareSameType()
:
: ===================================================================
: --- MutableValueDouble.java
: +++ MutableValueDouble.java
: @@ -54,9 +54,8 @@
: MutableValueDouble b = (MutableValueDouble)other;
: int c = Double.compare(value, b.value);
: if (c != 0) return c;
: - if (!exists) return -1;
: - if (!b.exists) return 1;
: - return 0;
: + if (exists == b.exists) return 0;
: + return exists ? 1 : -1;
: }
: ===================================================================
:
: I propose the following modifications: MutableValueBool.compareSameType()
:
: ===================================================================
: --- MutableValueBool.java
: +++ MutableValueBool.java
: @@ -52,7 +52,7 @@
: @Override
: public int compareSameType(Object other) {
: MutableValueBool b = (MutableValueBool)other;
: - if (value != b.value) return value ? 1 : 0;
: + if (value != b.value) return value ? 1 : -1;
: if (exists == b.exists) return 0;
: return exists ? 1 : -1;
: }
: ===================================================================
:
:
: Thanks,
:
: Ebisawa
:
:
-Hoss
http://www.lucidworks.com/
