[LUCENE-8902] Index-time join ToParentBlockJoinQuery query produces incorrect result with child wildcards

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 8.1.1
• Component/s: modules/join
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Andrei
• Created: 02/Jul/19 20:56
• Updated: 28/Aug/22 15:48
• Resolved: 03/Jul/19 10:04

Description

When I do a index-time join query on certain parent docs with a wildcard query for child docs, sometimes I get the wrong answer. Example:

 

Parent Doc	Children
id=id00000	none
id=id00001	program=P1
id=id00002	program=P1 program=P2
id=id00003	none
id=id00004	program=P1
id=id00005	program=P1 program=P2

So essentially I have 6 parent docs, doc 0 has no children, doc 1 has 1 child, doc 2 has 2 children, etc.

1. The following query gives the correct results:

        BitSetProducer parentSet = new QueryBitSetProducer(new TermInSetQuery("id", toSet("id00000", "id00001", "id00002", "id00003", "id00004", "id00005")));
        Query q = new ToParentBlockJoinQuery(new TermInSetQuery("program", toSet("P1", "P2")), parentSet, ScoreMode.None);

Returns the correct result (4 docs: ["id00001", "id00002", "id00004", "id00005"]

 

2. This also gives correct result (same as above):

        BitSetProducer parentSet = new QueryBitSetProducer(new TermInSetQuery("id", toSet("id00000", "id00001", "id00002", "id00003", "id00004", "id00005")));
        Query q = new ToParentBlockJoinQuery(new WildcardQuery(new Term("program", "*")), parentSet, ScoreMode.None);

 

3. Also correct (same as above)

        BitSetProducer parentSet = new QueryBitSetProducer(new WildcardQuery(new Term("id", "*")));
        Query q = new ToParentBlockJoinQuery(new WildcardQuery(new Term("program", "*")), parentSet, ScoreMode.None);

so far so good.

 

4. This one gives incorrect result:

        BitSetProducer parentSet = new QueryBitSetProducer(new TermInSetQuery("id", toSet("id00000", "id00001", "id00003")));
        Query q = new ToParentBlockJoinQuery(new WildcardQuery(new Term("program", "*")), parentSet, org.apache.lucene.search.join.ScoreMode.None);

Returns 2 docs ["id00001", "id00003"]. It should only return "id00001" and not "id00003" here. Very strange behavior.

 

5. Just asking for "id00003" also incorrectly returns it:

        BitSetProducer parentSet = new QueryBitSetProducer(new TermQuery(new Term("id", "id00003")));
        Query q = new ToParentBlockJoinQuery(new WildcardQuery(new Term("program", "*")), parentSet, org.apache.lucene.search.join.ScoreMode.None);

 

6. But as soon as I add "id00002" to the parent query, it works again..

        BitSetProducer parentSet = new QueryBitSetProducer(new TermInSetQuery("id", toSet( "id00003", "id00002")));
        Query q = new ToParentBlockJoinQuery(new WildcardQuery(new Term("program", "*")), parentSet, org.apache.lucene.search.join.ScoreMode.None);

Gives the correct result ["id00002"]

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I am attaching the unit test that demonstrates this: https://pastebin.com/aJ1LDLCS

I don't know if I am doing something wrong, or if there is an issue.

Thank you for looking into it.