From 942c54cf565894e55c33f615f20db571754948fa Mon Sep 17 00:00:00 2001
From: Michael Stack <stack@apache.org>
Date: Tue, 5 Aug 2008 19:05:48 +0000
Subject: [PATCH] HBASE-790 During import, single region blocks requests for
 >10 minutes, thread dumps, throws out pending requests, and continues

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@682874 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  3 ++
 .../hadoop/hbase/regionserver/Flusher.java    |  1 -
 .../hadoop/hbase/regionserver/HRegion.java    | 32 +++++++++++--------
 3 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index f0a611ed070..25e94b709a7 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -224,6 +224,9 @@ Release 0.2.0
    HBASE-751   dfs exception and regionserver stuck during heavy write load
    HBASE-793   HTable.getStartKeys() ignores table names when matching columns
                (Andrew Purtell and Dru Jensen via Stack)
+   HBASE-790   During import, single region blocks requests for >10 minutes,
+               thread dumps, throws out pending requests, and continues
+               (Jonathan Gray via Stack)
    
   IMPROVEMENTS
    HBASE-559   MR example job to count table rows
diff --git a/src/java/org/apache/hadoop/hbase/regionserver/Flusher.java b/src/java/org/apache/hadoop/hbase/regionserver/Flusher.java
index 8d6895b936d..6d30d5f4f07 100644
--- a/src/java/org/apache/hadoop/hbase/regionserver/Flusher.java
+++ b/src/java/org/apache/hadoop/hbase/regionserver/Flusher.java
@@ -237,7 +237,6 @@ class Flusher extends Thread implements FlushRequester {
       if (!regionsInQueue.contains(r)) {
         regionsInQueue.add(r);
         flushQueue.add(r);
-        r.setLastFlushTime(now);
       }
     }
   }
diff --git a/src/java/org/apache/hadoop/hbase/regionserver/HRegion.java b/src/java/org/apache/hadoop/hbase/regionserver/HRegion.java
index a713d1015a0..875eb7dfbec 100644
--- a/src/java/org/apache/hadoop/hbase/regionserver/HRegion.java
+++ b/src/java/org/apache/hadoop/hbase/regionserver/HRegion.java
@@ -317,7 +317,6 @@ public class HRegion implements HConstants {
     new ConcurrentHashMap<Integer, byte []>();
   private final Map<Integer, TreeMap<HStoreKey, byte []>> targetColumns =
       new ConcurrentHashMap<Integer, TreeMap<HStoreKey, byte []>>();
-  private volatile boolean flushRequested = false;
   // Default access because read by tests.
   final Map<Integer, HStore> stores = new ConcurrentHashMap<Integer, HStore>();
   final AtomicLong memcacheSize = new AtomicLong(0);
@@ -337,6 +336,8 @@ public class HRegion implements HConstants {
   static class WriteState {
     // Set while a memcache flush is happening.
     volatile boolean flushing = false;
+    // Set when a flush has been requested.
+    volatile boolean flushRequested = false;
     // Set while a compaction is running.
     volatile boolean compacting = false;
     // Gets set in close. If set, cannot compact or flush again.
@@ -355,6 +356,10 @@ public class HRegion implements HConstants {
     boolean isReadOnly() {
       return this.readOnly;
     }
+
+    boolean isFlushRequested() {
+      return this.flushRequested;
+    }
   }
 
   private volatile WriteState writestate = new WriteState();
@@ -689,11 +694,6 @@ public class HRegion implements HConstants {
     return this.lastFlushTime;
   }
   
-  /** @param t the lastFlushTime */
-  void setLastFlushTime(long t) {
-    this.lastFlushTime = t;
-  }
-  
   //////////////////////////////////////////////////////////////////////////////
   // HRegion maintenance.  
   //
@@ -946,7 +946,7 @@ public class HRegion implements HConstants {
     }
     synchronized (writestate) {
       if (!writestate.flushing && writestate.writesEnabled) {
-        writestate.flushing = true;
+        this.writestate.flushing = true;
       } else {
         if(LOG.isDebugEnabled()) {
           LOG.debug("NOT flushing memcache for region " + this +
@@ -968,6 +968,7 @@ public class HRegion implements HConstants {
     } finally {
       synchronized (writestate) {
         writestate.flushing = false;
+        this.writestate.flushRequested = false;
         writestate.notifyAll();
       }
     }
@@ -1008,7 +1009,6 @@ public class HRegion implements HConstants {
   private boolean internalFlushcache() throws IOException {
     final long startTime = System.currentTimeMillis();
     // Clear flush flag.
-    this.flushRequested = false;
     // Record latest flush time
     this.lastFlushTime = startTime;
     // If nothing to flush, return and avoid logging start/stop flush.
@@ -1411,7 +1411,7 @@ public class HRegion implements HConstants {
       releaseRowLock(lid);
     }
   }
-  
+
   /*
    * Check if resources to support an update.
    * 
@@ -1605,8 +1605,7 @@ public class HRegion implements HConstants {
         size = this.memcacheSize.addAndGet(
             getStore(key.getColumn()).add(key, e.getValue()));
       }
-      flush = this.flushListener != null && !this.flushRequested &&
-        isFlushSize(size);
+      flush = isFlushSize(size);
     } finally {
       this.updatesLock.readLock().unlock();
     }
@@ -1617,11 +1616,16 @@ public class HRegion implements HConstants {
   }
 
   private void requestFlush() {
-    if (this.flushListener == null || this.flushRequested) {
+    if (this.flushListener == null) {
       return;
     }
-    this.flushListener.request(this);
-    this.flushRequested = true;
+    synchronized (writestate) {
+      if (this.writestate.isFlushRequested()) {
+        return;
+      }
+      writestate.flushRequested = true;
+      this.flushListener.request(this);
+    }
     if (LOG.isDebugEnabled()) {
       LOG.debug("Flush requested on " + this);
     }