From 8e0d9849bd4c3c40293700c4eda24ef9e8a577d1 Mon Sep 17 00:00:00 2001
From: Adrien Grand <jpountz@gmail.com>
Date: Tue, 10 Jul 2018 08:47:41 +0200
Subject: [PATCH] LUCENE-8393: TieredMergePolicy needs to take into account the
 maximum segment size when computing the allowed number of segments.

---
 .../src/java/org/apache/lucene/index/TieredMergePolicy.java   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

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 34d7af694eb..499273daa5f 100644
--- a/lucene/core/src/java/org/apache/lucene/index/TieredMergePolicy.java
+++ b/lucene/core/src/java/org/apache/lucene/index/TieredMergePolicy.java
@@ -402,13 +402,13 @@ public class TieredMergePolicy extends MergePolicy {
     double allowedSegCount = 0;
     while (true) {
       final double segCountLevel = bytesLeft / (double) levelSize;
-      if (segCountLevel < segsPerTier) {
+      if (segCountLevel < segsPerTier || levelSize == maxMergedSegmentBytes) {
         allowedSegCount += Math.ceil(segCountLevel);
         break;
       }
       allowedSegCount += segsPerTier;
       bytesLeft -= segsPerTier * levelSize;
-      levelSize *= mergeFactor;
+      levelSize = Math.min(maxMergedSegmentBytes, levelSize * mergeFactor);
     }
 
     if (verbose(mergeContext) && tooBigCount > 0) {