[LUCENE-3129] Single-pass grouping collector based on doc blocks

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.2, 4.0-ALPHA
• Component/s: modules/grouping
• Lucene Fields: New
• Assignee: Michael McCandless
• Reporter: Michael McCandless
• Created: 20/May/11 20:57
• Updated: 28/Aug/22 12:47
• Resolved: 02/Jun/11 17:21

Description

LUCENE-3112 enables adding/updating a contiguous block of documents to
the index, guaranteed (yet, experimental!) to retain adjacent docID
assignment through the full life of the index as long the app doesn't
delete individual docs from the block.

When an app does this, it can enable neat features like LUCENE-2454
(nested documents), post-group facet counting (LUCENE-3097).

It also makes single-pass grouping possible, when you group by
the "identifier" field shared by the doc block, since we know we will
see a given group only once with all of its docs within one block.

This should be faster than the fully general two-pass collectors we
already have.

I'm working on a patch but not quite there yet...

Issue Links

• is blocked by: LUCENE-3112 Add IW.add/updateDocuments to support nested documents