[client] Fix issue where paused consumer receives new message when reconnecting #8165

massakam · 2020-09-30T01:31:37Z

Motivation

Consumers whose pause() method is called are expected not to fetch any more new messages from the broker until resume() is called. However, when the topic is unloaded or the broker is restarted, the consumer receives new messages.

While the consumer is paused, no flow permits are sent to the broker when the increaseAvailablePermits() method is called.

pulsar/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java

Lines 1527 to 1538 in dea574b

    
           protected void increaseAvailablePermits(ClientCnx currentCnx, int delta) { 
        
               int available = AVAILABLE_PERMITS_UPDATER.addAndGet(this, delta); 
        
               while (available >= receiverQueueRefillThreshold && !paused) { 
        
                   if (AVAILABLE_PERMITS_UPDATER.compareAndSet(this, available, 0)) { 
        
                       sendFlowPermitsToBroker(currentCnx, available); 
        
                       break; 
        
                   } else { 
        
                       available = AVAILABLE_PERMITS_UPDATER.get(this); 
        
                   } 
        
               } 
        
           }

However, if the sendFlowPermitsToBroker() method is called directly, flow permits will be sent even while the consumer is paused. When a reconnection occurs, sendFlowPermitsToBroker() is called instead of increaseAvailablePermits().

pulsar/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java

Lines 850 to 856 in dea574b

    
           // if the consumer is not partitioned or is re-connected and is partitioned, we send the flow 
        
           // command to receive messages. 
        
           // For readers too (isDurable==false), the partition idx will be set though we have to 
        
           // send available permits immediately after establishing the reader session 
        
           if (!(firstTimeConnect && hasParentConsumer && isDurable) && conf.getReceiverQueueSize() != 0) { 
        
               sendFlowPermitsToBroker(cnx, conf.getReceiverQueueSize()); 
        
           }

Modifications

Fixed consumer classes to always use increaseAvailablePermits() instead of sendFlowPermitsToBroker().

apache#8165) ### Motivation Consumers whose `pause()` method is called are expected not to fetch any more new messages from the broker until `resume()` is called. However, when the topic is unloaded or the broker is restarted, the consumer receives new messages. While the consumer is paused, no flow permits are sent to the broker when the `increaseAvailablePermits()` method is called. https://github.com/apache/pulsar/blob/dea574b3c6af7ea8eaa4904d8d6ed1044df00642/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L1527-L1538 However, if the `sendFlowPermitsToBroker()` method is called directly, flow permits will be sent even while the consumer is paused. When a reconnection occurs, `sendFlowPermitsToBroker()` is called instead of `increaseAvailablePermits()`. https://github.com/apache/pulsar/blob/dea574b3c6af7ea8eaa4904d8d6ed1044df00642/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L850-L856 ### Modifications Fixed consumer classes to always use `increaseAvailablePermits()` instead of `sendFlowPermitsToBroker()`.

#8165) ### Motivation Consumers whose `pause()` method is called are expected not to fetch any more new messages from the broker until `resume()` is called. However, when the topic is unloaded or the broker is restarted, the consumer receives new messages. While the consumer is paused, no flow permits are sent to the broker when the `increaseAvailablePermits()` method is called. https://github.com/apache/pulsar/blob/dea574b3c6af7ea8eaa4904d8d6ed1044df00642/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L1527-L1538 However, if the `sendFlowPermitsToBroker()` method is called directly, flow permits will be sent even while the consumer is paused. When a reconnection occurs, `sendFlowPermitsToBroker()` is called instead of `increaseAvailablePermits()`. https://github.com/apache/pulsar/blob/dea574b3c6af7ea8eaa4904d8d6ed1044df00642/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L850-L856 ### Modifications Fixed consumer classes to always use `increaseAvailablePermits()` instead of `sendFlowPermitsToBroker()`. (cherry picked from commit 4c489be)

apache#8165) ### Motivation Consumers whose `pause()` method is called are expected not to fetch any more new messages from the broker until `resume()` is called. However, when the topic is unloaded or the broker is restarted, the consumer receives new messages. While the consumer is paused, no flow permits are sent to the broker when the `increaseAvailablePermits()` method is called. https://github.com/apache/pulsar/blob/dea574b3c6af7ea8eaa4904d8d6ed1044df00642/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L1527-L1538 However, if the `sendFlowPermitsToBroker()` method is called directly, flow permits will be sent even while the consumer is paused. When a reconnection occurs, `sendFlowPermitsToBroker()` is called instead of `increaseAvailablePermits()`. https://github.com/apache/pulsar/blob/dea574b3c6af7ea8eaa4904d8d6ed1044df00642/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L850-L856 ### Modifications Fixed consumer classes to always use `increaseAvailablePermits()` instead of `sendFlowPermitsToBroker()`.

Fix issue where paused consumer receives new message when reconnecting

79d84fb

massakam added type/bug area/client release/2.6.2 labels Sep 30, 2020

massakam added this to the 2.7.0 milestone Sep 30, 2020

massakam self-assigned this Sep 30, 2020

sijie approved these changes Oct 2, 2020

View reviewed changes

sijie merged commit 4c489be into apache:master Oct 2, 2020

massakam deleted the fix-pause branch October 28, 2020 03:34

Lanayx mentioned this pull request Dec 2, 2020

Support for consumer pause and resume fsprojects/pulsar-client-dotnet#129

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[client] Fix issue where paused consumer receives new message when reconnecting #8165

[client] Fix issue where paused consumer receives new message when reconnecting #8165

massakam commented Sep 30, 2020

Uh oh!

	protected void increaseAvailablePermits(ClientCnx currentCnx, int delta) {
	int available = AVAILABLE_PERMITS_UPDATER.addAndGet(this, delta);

	while (available >= receiverQueueRefillThreshold && !paused) {
	if (AVAILABLE_PERMITS_UPDATER.compareAndSet(this, available, 0)) {
	sendFlowPermitsToBroker(currentCnx, available);
	break;
	} else {
	available = AVAILABLE_PERMITS_UPDATER.get(this);
	}
	}
	}

	// if the consumer is not partitioned or is re-connected and is partitioned, we send the flow
	// command to receive messages.
	// For readers too (isDurable==false), the partition idx will be set though we have to
	// send available permits immediately after establishing the reader session
	if (!(firstTimeConnect && hasParentConsumer && isDurable) && conf.getReceiverQueueSize() != 0) {
	sendFlowPermitsToBroker(cnx, conf.getReceiverQueueSize());
	}

[client] Fix issue where paused consumer receives new message when reconnecting #8165

[client] Fix issue where paused consumer receives new message when reconnecting #8165

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massakam commented Sep 30, 2020

Motivation

Modifications

Uh oh!