Added object allocation instrumentation for Column

- Modified CassandraDaemon to create allocation sampler before it starts the server; - Added allocations.jar to lib/
aryanet · Aug 14, 2013 · 3c7a9dd · 3c7a9dd
1 parent 7d4380d
commit 3c7a9dd
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diff --git a/lib/allocation.jar b/lib/allocation.jar
diff --git a/src/java/org/apache/cassandra/service/CassandraDaemon.java b/src/java/org/apache/cassandra/service/CassandraDaemon.java
@@ -19,6 +19,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.lang.instrument.UnmodifiableClassException;
 import java.net.InetAddress;
 import java.net.MalformedURLException;
 import java.net.URL;
@@ -45,6 +46,9 @@
 import org.apache.cassandra.utils.CLibrary;
 import org.apache.cassandra.utils.Mx4jTool;
 
+import com.google.monitoring.runtime.instrumentation.ConstructorCallback;
+import com.google.monitoring.runtime.instrumentation.ConstructorInstrumenter;
+
 /**
  * The <code>CassandraDaemon</code> is an abstraction for a Cassandra daemon
  * service, which defines not only a way to activate and deactivate it, but also
@@ -453,9 +457,28 @@ public static void stop(String[] args)
 
     public static void main(String[] args)
     {
+        instrumentAllocations();
         instance.activate();
     }
 
+    /*
+     * @see: https://code.google.com/p/java-allocation-instrumenter/wiki/GettingStarted
+     */
+    private static void instrumentAllocations() {
+        try {
+            ConstructorInstrumenter.instrumentClass(
+              Column.class, new ConstructorCallback<Column>() {
+                @Override public void sample(Column c) {
+                    if ((Math.random() * 10000) > 9998) {
+                        logger.info("Allocated a column", new Exception("Sample stacktrace"));
+                    }
+                }
+            });
+        } catch (UnmodifiableClassException e) {
+            System.out.println("Class cannot be modified");
+        }
+    }
+
     public interface Server
     {
         /**