From 40c45392b362d5abffe1dd59506964297eea5a20 Mon Sep 17 00:00:00 2001
From: Michael Stack <stack@apache.org>
Date: Wed, 14 Apr 2010 22:40:04 +0000
Subject: [PATCH] HBASE-2439 HBase can get stuck if updates to META are blocked

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@934231 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                                  | 2 ++
 .../java/org/apache/hadoop/hbase/regionserver/HRegion.java   | 4 ++++
 .../apache/hadoop/hbase/regionserver/MemStoreFlusher.java    | 5 ++++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index fa96139aa4f..262b735d956 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -269,6 +269,8 @@ Release 0.21.0 - Unreleased
    HBASE-2346  Usage of FilterList slows down scans
    HBASE-2341  ZK settings for initLimit/syncLimit should not have been removed
                from hbase-default.xml
+   HBASE-2439  HBase can get stuck if updates to META are blocked
+               (Kannan Muthukkaruppan via Stack)
 
   IMPROVEMENTS
    HBASE-1760  Cleanup TODOs in HTable
diff --git a/core/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java b/core/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
index 03dfe594daa..2fd9f3c09d8 100644
--- a/core/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
+++ b/core/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
@@ -1444,6 +1444,10 @@ public class HRegion implements HConstants, HeapSize { // , Writable{
    * the notify.
    */
   private void checkResources() {
+
+    // If catalog region, do not impose resource constraints or block updates.
+    if (this.getRegionInfo().isMetaRegion()) return;
+
     boolean blocked = false;
     while (this.memstoreSize.get() > this.blockingMemStoreSize) {
       requestFlush();
diff --git a/core/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreFlusher.java b/core/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreFlusher.java
index 7578446237e..7f63a610ec4 100644
--- a/core/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreFlusher.java
+++ b/core/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreFlusher.java
@@ -221,7 +221,10 @@ class MemStoreFlusher extends Thread implements FlushRequester {
     // queue if there's too many files.
     if (removeFromQueue) {
       checkStoreFileCount(region);
-    } else if (isTooManyStoreFiles(region)) {
+    } else if ((!region.getRegionInfo().isMetaRegion()) &&
+               isTooManyStoreFiles(region)) {
+      // Note: We don't impose blockingStoreFiles constraint on meta regions
+
       LOG.warn("Region " + region.getRegionNameAsString() + " has too many " +
           "store files, putting it back at the end of the flush queue.");
       server.compactSplitThread.compactionRequested(region, getName());