From 420a029b75b8ad5ef710a9a40a7d8596d67e0a62 Mon Sep 17 00:00:00 2001
From: Thomas White <tomwhite@apache.org>
Date: Wed, 2 Mar 2011 18:01:11 +0000
Subject: [PATCH] HADOOP-6754. DefaultCodec.createOutputStream() leaks memory.
 Contributed by Aaron Kimball.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1076314 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                         |  3 +++
 .../org/apache/hadoop/io/compress/DefaultCodec.java | 13 +++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index b01a49b0705..51f2c2d36c5 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -88,6 +88,9 @@ Trunk (unreleased changes)
     HADOOP-7153. MapWritable violates contract of Map interface for equals()
     and hashCode(). (Nicholas Telford via todd)
 
+    HADOOP-6754. DefaultCodec.createOutputStream() leaks memory.
+    (Aaron Kimball via tomwhite)
+
 Release 0.22.0 - Unreleased
 
   INCOMPATIBLE CHANGES
diff --git a/src/java/org/apache/hadoop/io/compress/DefaultCodec.java b/src/java/org/apache/hadoop/io/compress/DefaultCodec.java
index 0943f599eb9..1be28bfce36 100644
--- a/src/java/org/apache/hadoop/io/compress/DefaultCodec.java
+++ b/src/java/org/apache/hadoop/io/compress/DefaultCodec.java
@@ -19,18 +19,21 @@
 package org.apache.hadoop.io.compress;
 
 import java.io.IOException;
-import java.io.OutputStream;
 import java.io.InputStream;
+import java.io.OutputStream;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configurable;
 import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.io.compress.zlib.*;
+import org.apache.hadoop.io.compress.zlib.ZlibFactory;
 
 @InterfaceAudience.Public
 @InterfaceStability.Evolving
 public class DefaultCodec implements Configurable, CompressionCodec {
+  private static final Log LOG = LogFactory.getLog(DefaultCodec.class);
   
   Configuration conf;
 
@@ -44,6 +47,12 @@ public class DefaultCodec implements Configurable, CompressionCodec {
   
   public CompressionOutputStream createOutputStream(OutputStream out) 
   throws IOException {
+    // This may leak memory if called in a loop. The createCompressor() call
+    // may cause allocation of an untracked direct-backed buffer if native
+    // libs are being used (even if you close the stream).  A Compressor
+    // object should be reused between successive calls.
+    LOG.warn("DefaultCodec.createOutputStream() may leak memory. "
+        + "Create a compressor first.");
     return new CompressorStream(out, createCompressor(), 
                                 conf.getInt("io.file.buffer.size", 4*1024));
   }