From a864ef823167380eb1e2724b453c7730b93f5bbe Mon Sep 17 00:00:00 2001
From: Adrien Grand <jpountz@gmail.com>
Date: Tue, 10 Jul 2018 08:50:59 +0200
Subject: [PATCH] LUCENE-8394: Explicitly handle the case when segments are
 smaller than the floor size.

---
 .../src/java/org/apache/lucene/index/TieredMergePolicy.java    | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lucene/core/src/java/org/apache/lucene/index/TieredMergePolicy.java b/lucene/core/src/java/org/apache/lucene/index/TieredMergePolicy.java
index 499273daa5f..7f917bba46b 100644
--- a/lucene/core/src/java/org/apache/lucene/index/TieredMergePolicy.java
+++ b/lucene/core/src/java/org/apache/lucene/index/TieredMergePolicy.java
@@ -410,6 +410,9 @@ public class TieredMergePolicy extends MergePolicy {
       bytesLeft -= segsPerTier * levelSize;
       levelSize = Math.min(maxMergedSegmentBytes, levelSize * mergeFactor);
     }
+    // allowedSegCount may occasionally be less than segsPerTier
+    // if segment sizes are below the floor size
+    allowedSegCount = Math.max(allowedSegCount, segsPerTier);
 
     if (verbose(mergeContext) && tooBigCount > 0) {
       message("  allowedSegmentCount=" + allowedSegCount + " vs count=" + infos.size() +