[LUCENE-5883] Move MergePolicy to LiveIndexWriterConfig

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.10, 6.0
• Component/s: core/index
• Lucene Fields: New, Patch Available
• Assignee: Shai Erera
• Reporter: Shai Erera
• Created: 13/Aug/14 12:37
• Updated: 28/Aug/22 14:14
• Resolved: 14/Aug/14 11:43

Description

Since LUCENE-5711, MergePolicy is no longer wired to an IndexWriter instance. Therefore it can be moved to be a live setting on IndexWriter, which will allow apps to plug-in an MP on a live IW instance, without closing/reopening the writer. See for example LUCENE-5526 - instead of adding MP to forceMerge, apps could change the MP before calling forceMerge, with e.g. an UpgradeIndexMergePolicy.

I think we can also make MergeScheduler a live setting, though I currently don't see the benefits of doing that, so I'd rather not touch it now.