diff --git contrib/ambari-log4j/src/main/java/org/apache/ambari/log4j/hadoop/mapreduce/jobhistory/JobHistoryAppender.java contrib/ambari-log4j/src/main/java/org/apache/ambari/log4j/hadoop/mapreduce/jobhistory/JobHistoryAppender.java
index 7f9769e..b421f24 100644
--- contrib/ambari-log4j/src/main/java/org/apache/ambari/log4j/hadoop/mapreduce/jobhistory/JobHistoryAppender.java
+++ contrib/ambari-log4j/src/main/java/org/apache/ambari/log4j/hadoop/mapreduce/jobhistory/JobHistoryAppender.java
@@ -36,6 +36,8 @@ import org.apache.log4j.spi.LoggingEvent;
 public class JobHistoryAppender extends AppenderSkeleton implements Appender {
 
   private static final Log LOG = LogFactory.getLog(JobHistoryAppender.class);
+
+  public static final int QUEUE_CAPACITY = 256;
   
   private final Queue<LoggingEvent> events;
   private LoggingThreadRunnable logThreadRunnable;
@@ -63,7 +65,7 @@ public class JobHistoryAppender extends AppenderSkeleton implements Appender {
   private LogStore logStore;
   
   public JobHistoryAppender() {
-    events = new LinkedBlockingQueue<LoggingEvent>();
+    events = new LinkedBlockingQueue<LoggingEvent>(QUEUE_CAPACITY);
     logParser = new MapReduceJobHistoryParser();
     logStore = nullStore;
   }
@@ -116,30 +118,27 @@ public class JobHistoryAppender extends AppenderSkeleton implements Appender {
           logStore = 
               new DatabaseStore(driver, database, user, password, 
                   new MapReduceJobHistoryUpdater());
+          logThreadRunnable =
+                  new LoggingThreadRunnable(events, logParser, logStore);
+          logThread = new Thread(logThreadRunnable);
+          logThread.setDaemon(true);
+          logThread.start();
         } catch (IOException ioe) {
-          LOG.debug("Failed to connect to db " + database, ioe);
+          LOG.warn("Failed to connect to db " + database, ioe);
           System.err.println("Failed to connect to db " + database + 
               " as user " + user + " password " + password + 
               " and driver " + driver + " with " + 
               StringUtils.stringifyException(ioe));
-          throw new RuntimeException(
-              "Failed to create database store for " + database, ioe);
         } catch (Exception e) {
-          LOG.debug("Failed to connect to db " + database, e);
+          LOG.warn("Failed to connect to db " + database +
+                  " as user " + user + " password " + password +
+                  " and driver " + driver, e);
           System.err.println("Failed to connect to db " + database + 
               " as user " + user + " password " + password + 
               " and driver " + driver + " with " + 
               StringUtils.stringifyException(e));
-          throw new RuntimeException(
-              "Failed to create database store for " + database, e);
         }
       }
-      logThreadRunnable = 
-          new LoggingThreadRunnable(events, logParser, logStore);
-      logThread = new Thread(logThreadRunnable);
-      logThread.setDaemon(true);
-      logThread.start();
-
       super.activateOptions();
     }
   }
@@ -150,11 +149,15 @@ public class JobHistoryAppender extends AppenderSkeleton implements Appender {
       logThreadRunnable.close();
     } catch (IOException ioe) {
       LOG.info("Failed to close logThreadRunnable", ioe);
+    } catch (Exception e) {
+      LOG.info("Failed to close logThreadRunnable", e);
     }
     try {
       logThread.join(1000);
     } catch (InterruptedException ie) {
       LOG.info("logThread interrupted", ie);
+    } catch (Exception e) {
+      LOG.info("logThread interrupted", e);
     }
   }
 
@@ -164,7 +167,14 @@ public class JobHistoryAppender extends AppenderSkeleton implements Appender {
   }
 
   @Override
-  protected void append(LoggingEvent event) {
-    events.add(event);
+  public void append(LoggingEvent event) {
+    if (!events.offer(event)) {
+      //fail, queue is full, there is a chance database is down
+      LOG.warn("workflow event queue full, there is a chance database is down");
+    }
+  }
+
+  public Queue<LoggingEvent> getEventQueue() {
+    return events;
   }
 }
diff --git contrib/ambari-log4j/src/test/java/org/apache/ambari/TestJobHistoryAppender.java contrib/ambari-log4j/src/test/java/org/apache/ambari/TestJobHistoryAppender.java
new file mode 100644
index 0000000..55167a7
--- /dev/null
+++ contrib/ambari-log4j/src/test/java/org/apache/ambari/TestJobHistoryAppender.java
@@ -0,0 +1,60 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.ambari;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+import org.apache.ambari.log4j.hadoop.mapreduce.jobhistory.JobHistoryAppender;
+import org.apache.log4j.Category;
+import org.apache.log4j.spi.LoggingEvent;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+
+/**
+ *
+ */
+public class TestJobHistoryAppender extends TestCase {
+
+  public void testEventQueueCapacity() throws IllegalAccessException,
+          InstantiationException, InvocationTargetException, NoSuchMethodException {
+    JobHistoryAppender jobHistoryAppender = new JobHistoryAppender();
+    Constructor<?> constructor = Category.class.getDeclaredConstructor(String.class);
+    constructor.setAccessible(true);
+    Category c = (Category) constructor.newInstance("test");
+    for (int i = 0; i < JobHistoryAppender.QUEUE_CAPACITY; i++) {
+      LoggingEvent event = newLoggingEvent(c);
+      jobHistoryAppender.append(event);
+    }
+    Assert.assertTrue(jobHistoryAppender.getEventQueue().size() ==
+            JobHistoryAppender.QUEUE_CAPACITY);
+    LoggingEvent event = newLoggingEvent(c);
+    try {
+      jobHistoryAppender.append(event);
+    } catch (Exception e) {
+      fail("jobHistoryAppender should not throw an exception \n" + e);
+    }
+    Assert.assertTrue(jobHistoryAppender.getEventQueue().size() ==
+            JobHistoryAppender.QUEUE_CAPACITY);
+  }
+
+  private LoggingEvent newLoggingEvent(Category c) throws IllegalAccessException,
+          InvocationTargetException, InstantiationException {
+    return new LoggingEvent(null, c, null, null, null);
+  }
+
+}