diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index 491b62c41e1..e1785ebebcc 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -117,6 +117,9 @@ New Features
 
 * LUCENE-6077: Added a filter cache. (Adrien Grand, Robert Muir)
 
+* LUCENE-6089, LUCENE-6090: Tune CompressionMode.HIGH_COMPRESSION for 
+  better compression and less cpu usage. (Adrien Grand, Robert Muir)
+
 API Changes
 
 * LUCENE-5900: Deprecated more constructors taking Version in *InfixSuggester and
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/compressing/CompressionMode.java b/lucene/core/src/java/org/apache/lucene/codecs/compressing/CompressionMode.java
index 600fd3c1ec6..e7670661db3 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/compressing/CompressionMode.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/compressing/CompressionMode.java
@@ -186,7 +186,7 @@ public abstract class CompressionMode {
     byte[] compressed;
 
     DeflateDecompressor() {
-      decompressor = new Inflater();
+      decompressor = new Inflater(true);
       compressed = new byte[0];
     }
 
@@ -198,13 +198,18 @@ public abstract class CompressionMode {
         return;
       }
       final int compressedLength = in.readVInt();
-      if (compressedLength > compressed.length) {
-        compressed = new byte[ArrayUtil.oversize(compressedLength, 1)];
+      // pad with extra "dummy byte": see javadocs for using Inflater(true)
+      // we do it for compliance, but its unnecessary for years in zlib.
+      final int paddedLength = compressedLength + 1;
+      if (paddedLength > compressed.length) {
+        compressed = new byte[ArrayUtil.oversize(paddedLength, 1)];
       }
       in.readBytes(compressed, 0, compressedLength);
+      compressed[compressedLength] = 0; // explicitly set dummy byte to 0
 
       decompressor.reset();
-      decompressor.setInput(compressed, 0, compressedLength);
+      // extra "dummy byte"
+      decompressor.setInput(compressed, 0, paddedLength);
 
       bytes.offset = bytes.length = 0;
       while (true) {
@@ -242,7 +247,7 @@ public abstract class CompressionMode {
     byte[] compressed;
 
     DeflateCompressor(int level) {
-      compressor = new Deflater(level);
+      compressor = new Deflater(level, true);
       compressed = new byte[64];
     }