To-parent block joins should implement two-phase iteration [LUCENE-7654]

[asfimport]

To-parent block joins are a good fit for two-phase iteration. Currently the iterator implementation visits all child matches before returning a parent match. Instead, an approximation would only need to find one child match in order to return a potential parent match. This would make to-parent block joins more efficient when used in conjunctions.

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Migrated from LUCENE-7654 by Adrien Grand (@jpountz), resolved Jan 30 2017
Attachments: LUCENE-7654.patch
Linked issues:

• Remove ToParentBlockJoinCollector [LUCENE-6959] #8016
• Calculating minimum score instead of maximum score in ToParentBlockJoinQuery.BlockJoinScorer.setScoreAndFreq [LUCENE-7833] #8884

[asfimport]

Adrien Grand (@jpountz) (migrated from JIRA)

Here is a patch that implements both scorerSupplier and twoPhaseIterator for to-parent block joins. It cannot be committed right now because it would cause bugs with ToParentBlockJoinCollector. The latter currently relies on the fact that if a sub scorer returns the current doc with the docId() method, then it means that it matches, which is not true with two-phase iteration.

[asfimport]

ASF subversion and git services (migrated from JIRA)

Commit b6b44d4 in lucene-solr's branch refs/heads/branch_6x from @jpountz
https://git-wip-us.apache.org/repos/asf?p=lucene-solr.git;h=b6b44d4

LUCENE-7654: To-parent block joins should implement two-phase iteration.

[asfimport]

ASF subversion and git services (migrated from JIRA)

Commit 9d5dc0c in lucene-solr's branch refs/heads/master from @jpountz
https://git-wip-us.apache.org/repos/asf?p=lucene-solr.git;h=9d5dc0c

LUCENE-7654: To-parent block joins should implement two-phase iteration.