[LUCENE-8398] TieredMergePolicy.getMaxMergedSegmentMB has rounding error

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 7.5, 8.0
• Component/s: core/other
• Lucene Fields: New
• Assignee: Erick Erickson
• Reporter: Erick Erickson
• Created: 16/Jul/18 00:18
• Updated: 28/Aug/22 15:32
• Resolved: 16/Jul/18 15:48

Description

This is largely a test artifact since it's unlikely to show up for realistically sized segments, but the fix is simple and safe.

This code first does long division then promotes to double for the last calculation.

 return maxMergedSegmentBytes/1024/1024.;

The error can be reproduced with: -Dtests.seed=EF80BCABAD74A7CF