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https://issues.apache.org/jira/browse/AMQ-5086?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hadrian Zbarcea updated AMQ-5086:
---------------------------------
Fix Version/s: 5.10.1
> vm transport create=false&waitForStart race condition
> -----------------------------------------------------
>
> Key: AMQ-5086
> URL: https://issues.apache.org/jira/browse/AMQ-5086
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.7.0, 5.8.0, 5.9.0
> Reporter: Christian Mamen
> Fix For: 5.10.1, 5.11.0
>
> Attachments: AMQ5086.patch
>
>
> Experience this bug on 5.7.0, I think this is the same on the trunk
> using vm transport for a client to connect to an embedded broker, in a
> multithreaded application, I'm experiencing a an error (sometimes) which
> appears to be a race condition at startup.
> Im using create=false and waitForStart to create a connectionFactory for a
> client connection
> vm://ApplicationName?create=false&waitForStart=120000
> The broker service is started in a seperate thread
> the client connection is started first. but surprisingly it tries start the
> brokers transport connector. An apparent glitch follows when the broker
> service stops and re-start the transport.
> {noformat}
> 2014-03-05 11:07:57,626 [ClientConnection_thread] INFO
> org.apache.activemq.broker.TransportConnector - Connector
> vm://ApplicationName Started
> [...]
> 2014-03-05 11:08:07,009 [Main_thread] INFO
> org.apache.activemq.broker.TransportConnector - Connector
> vm://ApplicationName Stopped
> 2014-03-05 11:08:07,011 [Main_thread] INFO
> org.apache.activemq.broker.TransportConnector - Connector
> vm://ApplicationName Started
> {noformat}
> I look into the activemq source and saw this:
> BrokerService.class
> {code}
> public void start() throws Exception {
> [...]
> // in jvm master slave, lets not publish over existing broker till we get
> the lock
> final BrokerRegistry brokerRegistry = BrokerRegistry.getInstance();
> if (brokerRegistry.lookup(getBrokerName()) == null) {
> brokerRegistry.bind(getBrokerName(), BrokerService.this);
> }
> startPersistenceAdapter(startAsync);
> startBroker(startAsync);
> brokerRegistry.bind(getBrokerName(), BrokerService.this);
> {code}
> VMTransportFactory.class
> {code}
> private BrokerService lookupBroker(final BrokerRegistry registry, final
> String brokerName, int waitForStart) {
> BrokerService broker = null;
> synchronized(registry.getRegistryMutext()) {
> broker = registry.lookup(brokerName);
> if (broker == null && waitForStart > 0) {
> final long expiry = System.currentTimeMillis() + waitForStart;
> while (broker == null && expiry >
> System.currentTimeMillis()) {
> long timeout = Math.max(0, expiry -
> System.currentTimeMillis());
> try {
> LOG.debug("waiting for broker named: " + brokerName +
> " to start");
> registry.getRegistryMutext().wait(timeout);
> } catch (InterruptedException ignored) {
> }
> broker = registry.lookup(brokerName);
> }
> }
> }
> return broker;
> }
> {code}
> It appears that create=false and waitForStart only waits for the broker to be
> added to the BrokerRegistry. However when the brokerService is starts, it
> seems that the broker is added to the registry before it is started.
> I believe some synchronization is missing make the VMTransportFactory wait
> for the broker not only to be added to the registry, but also fully started.
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