[SOLR-2604] Backport Join support to Solr 3.x

• Type: New Feature
• Status: Resolved
• Priority: Minor
• Resolution: Won't Fix
• Component/s: search
• Assignee: Unassigned
• Reporter: Doug Mittendorf
• Created: 17/Jun/11 18:28
• Updated: 18/Nov/13 11:38
• Resolved: 18/Nov/13 11:38

Description

Join support was recently added to Solr trunk (4.0) via SOLR-2272. We have a need for this functionality, but don't want to upgrade to trunk, so I spent some time back-porting the feature to work with the 3.x APIs. Not all of the optimizations that Yonik implemented have been ported since the 3.x APIs don't allow the same low-level access to the index, but the basic functionality is in place and seems to work well when joining between an index with 1.2M docs and another with 300k docs.

I still have yet to back-port the unit tests as those are heavily dependent on other 4.0 code, but wanted to go ahead and post the initial code in case others can make use of it.