From f60e26e77178a34e87c8e5c6d907f70a18207801 Mon Sep 17 00:00:00 2001
From: Jean-Daniel Cryans <jdcryans@apache.org>
Date: Fri, 2 Apr 2010 00:55:03 +0000
Subject: [PATCH] HBASE-2087  The wait on compaction because "Too many store
 files"             holds up all flushing

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@930143 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  2 ++
 .../hbase/regionserver/MemStoreFlusher.java   | 29 ++++++++++++++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index f73fb1aed32..2b7c5db2925 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -479,6 +479,8 @@ Release 0.21.0 - Unreleased
    HBASE-2388  Give a very explicit message when we figure a big GC pause
    HBASE-2270  Improve how we handle recursive calls in ExplicitColumnTracker 
                and WildcardColumnTracker
+   HBASE-2087  The wait on compaction because "Too many store files" 
+               holds up all flushing
 
   NEW FEATURES
    HBASE-1961  HBase EC2 scripts
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 abc763f7566..7578446237e 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
@@ -215,7 +215,25 @@ class MemStoreFlusher extends Thread implements FlushRequester {
    * not flushed.
    */
   private boolean flushRegion(HRegion region, boolean removeFromQueue) {
-    checkStoreFileCount(region);
+    // if removeFromQueue, then we come from flushSomeRegions and we need
+    // to block if there's too many store files. Else, we don't want to hang
+    // the main flushing thread so we'll just the region at the end of the
+    // queue if there's too many files.
+    if (removeFromQueue) {
+      checkStoreFileCount(region);
+    } else if (isTooManyStoreFiles(region)) {
+      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());
+      // If there's only this item in the queue or they are all in this
+      // situation, we will loop at lot. Sleep a bit.
+      try {
+        Thread.sleep(1000);
+      } catch (InterruptedException e) { } // just continue
+      flushQueue.add(region);
+      // Tell a lie, it's not flushed but it's ok
+      return true;
+    }
     synchronized (regionsInQueue) {
       // See comment above for removeFromQueue on why we do not
       // take the region out of the set. If removeFromQueue is true, remove it
@@ -303,6 +321,15 @@ class MemStoreFlusher extends Thread implements FlushRequester {
     }
   }
 
+  private boolean isTooManyStoreFiles(HRegion region) {
+    for (Store hstore: region.stores.values()) {
+      if (hstore.getStorefilesCount() > this.blockingStoreFilesNumber) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   /**
    * Check if the regionserver's memstore memory usage is greater than the 
    * limit. If so, flush regions with the biggest memstores until we're down