QPID-4428: HA add UUID tag to avoid using an out of date queue/exchange.

Imagine a cluster with primary A and backups B and C. A queue Q is created on A
and replicated to B, C. Now A dies and B takes over as primary. Before C can
connect to B, a client destroys Q and creates a new queue with the same name.
When B connects it sees Q and incorrectly assumes it is the same Q that it has
already replicated. Now C has an inconsistent replica of Q.

The fix is to tag queues/exchanges with a UUID so a backup can tell if a queue
is not the same as the one it has already replicated, even if the names are the
same.  This all also applies to exchanges.

- Minor imrovements to printing UUIDs in a FieldTable.
- Fix comparison of void Variants, added operator !=

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1409241 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 5 insertions, 1 deletions

diff --git a/qpid/cpp/src/qpid/broker/Queue.h b/qpid/cpp/src/qpid/broker/Queue.h
index 3fa8391d46..eecc8ce433 100644
--- a/qpid/cpp/src/qpid/broker/Queue.h
+++ b/qpid/cpp/src/qpid/broker/Queue.h
@@ -145,7 +145,7 @@ class Queue : public boost::enable_shared_from_this<Queue>,
     mutable qpid::sys::Mutex messageLock;
     mutable qpid::sys::Mutex ownershipLock;
     mutable uint64_t persistenceId;
-    const QueueSettings settings;
+    QueueSettings settings;
     qpid::framing::FieldTable encodableSettings;
     QueueDepth current;
     QueueBindings bindings;
@@ -423,6 +423,10 @@ class Queue : public boost::enable_shared_from_this<Queue>,
 
     uint32_t getDequeueSincePurge() { return dequeueSincePurge.get(); }
     QPID_BROKER_EXTERN void setDequeueSincePurge(uint32_t value);
+
+    /** Add an argument to be included in management messages about this queue. */
+    void addArgument(const std::string& key, const types::Variant& value);
+
   friend class QueueFactory;
 };
 }