From 80dbf06651e527ec0421ce51e4712ffb2f1d078b Mon Sep 17 00:00:00 2001
From: Lars Hofhansl <larsh@apache.org>
Date: Wed, 8 Apr 2015 21:43:01 -0700
Subject: [PATCH] HBASE-13362 Set max result size from client only (like
 scanner caching).

---
 .../org/apache/hadoop/hbase/HConstants.java   | 25 ++++++++++++++++---
 .../src/main/resources/hbase-default.xml      | 10 ++++++++
 .../hbase/regionserver/RSRpcServices.java     |  4 +--
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/HConstants.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/HConstants.java
index 19e251ae805..fc65c474e6f 100644
--- a/hbase-common/src/main/java/org/apache/hadoop/hbase/HConstants.java
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/HConstants.java
@@ -612,13 +612,20 @@ public final class HConstants {
    */
   public static final UUID DEFAULT_CLUSTER_ID = new UUID(0L,0L);
 
-    /**
-     * Parameter name for maximum number of bytes returned when calling a
-     * scanner's next method.
-     */
+  /**
+   * Parameter name for maximum number of bytes returned when calling a scanner's next method.
+   * Controlled by the client.
+   */
   public static final String HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE_KEY =
       "hbase.client.scanner.max.result.size";
 
+  /**
+   * Parameter name for maximum number of bytes returned when calling a scanner's next method.
+   * Controlled by the server.
+   */
+  public static final String HBASE_SERVER_SCANNER_MAX_RESULT_SIZE_KEY =
+      "hbase.server.scanner.max.result.size";
+
   /**
    * Maximum number of bytes returned when calling a scanner's next method.
    * Note that when a single row is larger than this limit the row is still
@@ -628,6 +635,16 @@ public final class HConstants {
    */
   public static final long DEFAULT_HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE = 2 * 1024 * 1024;
 
+  /**
+   * Maximum number of bytes returned when calling a scanner's next method.
+   * Note that when a single row is larger than this limit the row is still
+   * returned completely.
+   * Safety setting to protect the region server.
+   *
+   * The default value is 100MB. (a client would rarely request larger chunks on purpose)
+   */
+  public static final long DEFAULT_HBASE_SERVER_SCANNER_MAX_RESULT_SIZE = 100 * 1024 * 1024;
+
   /**
    * Parameter name for client pause value, used mostly as value to wait
    * before running a retry of a failed get, region lookup, etc.
diff --git a/hbase-common/src/main/resources/hbase-default.xml b/hbase-common/src/main/resources/hbase-default.xml
index 93776d7d841..c51ba16bc81 100644
--- a/hbase-common/src/main/resources/hbase-default.xml
+++ b/hbase-common/src/main/resources/hbase-default.xml
@@ -1306,6 +1306,16 @@ possible configurations would overwhelm and obscure the important.
     </description>
   </property>
 
+  <property>
+    <name>hbase.server.scanner.max.result.size</name>
+    <value>104857600</value>
+    <description>Maximum number of bytes returned when calling a scanner's next method.
+    Note that when a single row is larger than this limit the row is still returned completely.
+    The default value is 100MB.
+    This is a safety setting to protect the server from OOM situations.
+    </description>
+  </property>
+
   <property>
     <name>hbase.status.published</name>
     <value>false</value>
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
index 10e39a18b13..f9b8d610040 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
@@ -820,8 +820,8 @@ public class RSRpcServices implements HBaseRPCErrorHandler,
       HConstants.HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD,
       HConstants.DEFAULT_HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD);
     maxScannerResultSize = rs.conf.getLong(
-      HConstants.HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE_KEY,
-      HConstants.DEFAULT_HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE);
+      HConstants.HBASE_SERVER_SCANNER_MAX_RESULT_SIZE_KEY,
+      HConstants.DEFAULT_HBASE_SERVER_SCANNER_MAX_RESULT_SIZE);
 
     // Set our address, however we need the final port that was given to rpcServer
     isa = new InetSocketAddress(initialIsa.getHostName(), rpcServer.getListenerAddress().getPort());