Author: rjung
Date: Sun Mar 29 14:17:16 2009
New Revision: 759694
URL: http://svn.apache.org/viewvc?rev=759694&view=rev
Log:
Fix locking in FastAsyncSocketSender:
Locking in DataSender and the sub class FastAsyncSocketSender
uses the same lock, although the reasons for locking are totally
independent.
- FastAsyncSocketSender only locks for assuring atomicity of internal
statistics counter manipulation.
- DataSender locks access to sockets and other things.
When a node crashes, sharing the same lock leads the request
handling threads to block in the replication valve, because
the replication sender thread keeps the lock while trying
to establish a new connection to the crashed node.
This problem stops, as soon as the membership drops the node,
but keeps a growing number of connector threads blocked
until that happens.
Using a separate mutex for the local statistics manipulations will
no longer block the request handling threads.
Modified:
tomcat/sandbox/tomcat-oacc/trunk/src/share/org/apache/catalina/cluster/tcp/FastAsyncSocketSender.java
Modified:
tomcat/sandbox/tomcat-oacc/trunk/src/share/org/apache/catalina/cluster/tcp/FastAsyncSocketSender.java
URL:
http://svn.apache.org/viewvc/tomcat/sandbox/tomcat-oacc/trunk/src/share/org/apache/catalina/cluster/tcp/FastAsyncSocketSender.java?rev=759694&r1=759693&r2=759694&view=diff
==============================================================================
---
tomcat/sandbox/tomcat-oacc/trunk/src/share/org/apache/catalina/cluster/tcp/FastAsyncSocketSender.java
(original)
+++
tomcat/sandbox/tomcat-oacc/trunk/src/share/org/apache/catalina/cluster/tcp/FastAsyncSocketSender.java
Sun Mar 29 14:17:16 2009
@@ -92,6 +92,13 @@
private int threadPriority = Thread.NORM_PRIORITY;;
+ /**
+ * Separate mutex for our local state.
+ * We keep the synchronization independent of the synchronization
+ * in the super class DataSender.
+ */
+ private Object mutex = new Object();
+
// -------------------------------------------------------------
Constructor
/**
@@ -354,7 +361,7 @@
public void sendMessage(ClusterData data)
throws java.io.IOException {
queue.add(data.getUniqueId(), data);
- synchronized (this) {
+ synchronized (mutex) {
inQueueCounter++;
if(queueThread != null)
queueThread.incQueuedNrOfBytes(data.getMessage().length);
@@ -456,15 +463,15 @@
return queuedNrOfBytes;
}
- protected synchronized void setQueuedNrOfBytes(long queuedNrOfBytes) {
+ protected void setQueuedNrOfBytes(long queuedNrOfBytes) {
this.queuedNrOfBytes = queuedNrOfBytes;
}
- protected synchronized void incQueuedNrOfBytes(long size) {
+ protected void incQueuedNrOfBytes(long size) {
queuedNrOfBytes += size;
}
- protected synchronized void decQueuedNrOfBytes(long size) {
+ protected void decQueuedNrOfBytes(long size) {
queuedNrOfBytes -= size;
}
@@ -562,8 +569,10 @@
.getKey()), x);
}
} finally {
- outQueueCounter++;
- decQueuedNrOfBytes(messagesize);
+ synchronized (sender.mutex) {
+ outQueueCounter++;
+ decQueuedNrOfBytes(messagesize);
+ }
}
entry = entry.next();
} while (keepRunning && entry != null);
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