[LUCENE-7561] Add back-compat indices for index sorting

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 6.4, 7.0
• Lucene Fields: New
• Assignee: Michael McCandless
• Reporter: Michael McCandless
• Created: 15/Nov/16 10:53
• Updated: 28/Aug/22 15:06
• Resolved: 16/Nov/16 17:09

Description

Index time sorting is a powerful feature making searches that are "congruent" with the sort much faster, in exchange for slower indexing. For some use cases this is a great tradeoff.

We recently promoted the feature to core (LUCENE-6766) and made it very simple to use (you just call IndexWriterConfig.setIndexSort. In LUCENE-7537 we are adding support for multi-valued fields.

I think it's important we properly test backwards compatibility and from a quick look it looks like we have no sorted indices in TestBackwardsCompatibility ...