[AMQCPP-325] Failover transport exception can cause CPU spin

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 3.2.3
• Component/s: Transports

Environment

Windows 2003, Windows 7, Windows XP

• Assignee: Timothy A. Bish
• Reporter: FangYu
• Created: 02/Nov/10 05:03
• Updated: 04/Nov/10 20:17
• Resolved: 04/Nov/10 20:17

Description

We find that when use the failover transport to connect the broker, if failed to connect, then the thread will not release and become a DEADLESS LOOP cause CPU spin.

See the source code:

file: ~\activemq-cpp-library-3.2.3\src\main\activemq\transport\failover\failovertransport.cpp
500 bool FailoverTransport::iterate() {
......................................................................
510 if( connectedTransport != NULL || closed || connectionFailure != NULL )

{ 511 return false; ...................................................................... 702 }

file: ~\activemq-cpp-library-3.2.3\src\main\activemq\threads\compositetaskrunner.cpp
97 void CompositeTaskRunner::run() {
98
99 try {
100
101 while( true ) {
102
103 synchronized( &mutex ) {
104 pending = false;
105 if( shutDown )

{ 106 return; 107 }

108 }
109
110 if( !this->iterate() ) {
111
112 // wait to be notified.
113 synchronized( &mutex ) {
114 if( shutDown )

{ 115 return; 116 }

117 while( !pending )

{ 118 mutex.wait(); 119 }

120 }
121 }
122 }
123 }
124 AMQ_CATCH_NOTHROW( Exception )
125 AMQ_CATCHALL_NOTHROW()
126
127 // Make sure we notify any waiting threads that thread
128 // has terminated.
129 synchronized( &mutex )

{ 130 threadTerminated = true; 131 mutex.notifyAll(); 132 }

133 }

............................................................................

160 bool CompositeTaskRunner::iterate() {
161
162 synchronized( &tasks ) {
163
164 auto_ptr< Iterator<CompositeTask*> > iter( tasks.iterator() );
165
166 while( iter->hasNext() ) {
167
168 CompositeTask* task = iter->next();
169
170 if( task->isPending() )

{ 171 task->iterate() ; 173 174 // Always return true, so that we check again for 175 // any of the other tasks that might now be pending. 176 return true; 177 }

178 }
179 }
180
181 return false;
182 }