Rob Waite created AMQNET-409:
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Summary: Failover fails under load. Client goes into reconnect
loop.
Key: AMQNET-409
URL: https://issues.apache.org/jira/browse/AMQNET-409
Project: ActiveMQ .Net
Issue Type: Bug
Components: ActiveMQ
Affects Versions: 1.5.6
Environment: Should not matter. AMQ is on Linux, Client is on Windows
with .NET 4
Reporter: Rob Waite
Assignee: Jim Gomes
We were testing failover under heavy load. We have a queue that I placed 500k
messages in. I then have 5 consumers pulling them as fast as they can. The
operations are noops essentially... so messages are consumed in our case at
around 500 messages per second with our prod servers.
I would bring up the consumers and they would be consuming away. I would then
"kill -9" AMQ and then observe the client. From the AMQ web admin... they would
come back but you would see the 5 consumers go back and forth between 5 and 0
and comsumption went down from 500/s to about 3/s.
Looking at AMQ logs... there was a series of errors like this " Async error
occurred: javax.jms.JMSException: Unmatched acknowledge: MessageAck" and then
there would be a couple variations of exceptions regarding the connection being
lost (EOFException, broken pipe, etc).
I can provide the full stack traces but I have already found the line that
seems to cause the client to reconnect, fail, disconnect ad infinitum.
In our particular case... there is a line in the NMS source in Connection.cs
line 950 that looks like:
Tracer.DebugFormat("Connection[{0}]: Async exception with no exception
listener: " + error, this.ConnectionId);
The error variable was populated with:
"Apache.NMS.NMSConnectionException: Unmatched acknowledge: MessageAck
{commandId = 1146, responseRequired = false, ackType = 2, consumerId =
ID:kpc-eng-d27-54512-634956893773509011-1:10:3:1, firstMessageId =
ID:qawin-ops01-54879-634956774946428300-1:0:1:2:60645, lastMessageId =
ID:qawin-ops01-54879-634956774946428300-1:0:1:2:60645, destination =
queue://AAA.RwwTest.Failover, transactionId = null, messageCount = 1,
poisonCause = null}; Could not find Message-ID
ID:qawin-ops01-54879-634956774946428300-1:0:1:2:60645 in dispatched-list (start
of ack)"
Notice that there are curly braces in there... when you try to pass this string
into the Tracer.DebugFormat call you get a System.FormatException with the
message "Input string was not in a correct format."
It seems odd that String.Format style logging is used but a string is still
concatenated. This seems to happen many places in the code. I would think that
either the Tracer should handle this exception or DebugFormat should be used
properly.
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