Juri Robl created AMQNET-564:
--------------------------------
Summary: Individual Acknowledgements are slow for large amounts of
messages
Key: AMQNET-564
URL: https://issues.apache.org/jira/browse/AMQNET-564
Project: ActiveMQ .Net
Issue Type: Bug
Components: ActiveMQ
Affects Versions: 1.7.2
Environment: .NET 4.5.2
Apache.NMS 1.7.1
Apache.NMS.ActiveMQ 1.7.2
Reporter: Juri Robl
Priority: Minor
When using the asynchronious Listener, the consumer gets pushed as many
messages as possible from the queue. Using Individual Acknowledgement-Mode all
messages need to be Acked.
When the consumer loads many messages (>>25.000) the Ack. performance degrades
badly (< 20 messages / s).
New messages the consumer recieves are stored at the front of a LinkedList.
Before the ack is send, the Consumer searches the list front-to-end. Because I
(and most people probably) want to ack one of the oldest messages, the whole
list needs to be traversed. Afterwards the found message is removed from the
list, which traverses the list once again.
The Code in question from MessageConsumer.cs:
{code}
foreach (MessageDispatch originalDispatch in this.deliveredMessages)
{
if (originalDispatch.Message.MessageId.Equals(message.MessageId))
{
dispatch = originalDispatch;
this.deliveredMessages.Remove(originalDispatch);
break;
}
}
{code}
I tried two changes to the code, and it is orders of magnitude faster for large
amounts of messages (if the oldest message always needs to be acked). I used
reflection to access the needed methods/fields because I had some problems
compiling the original code.
{code}
// Reverse the iteration
for (var deliveredMessageNode = deliveredMessages.Last; deliveredMessageNode !=
null; deliveredMessageNode = deliveredMessageNode.Previous)
{
var deliveredMessage = deliveredMessageNode.Value;
if
(deliveredMessage.Message.MessageId.Equals(message.MessageId))
{
dispatch = deliveredMessage;
// Use the node to remove the message, don't search again for it
deliveredMessages.Remove(deliveredMessageNode);
break;
}
}
{code}
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