Hi Josh,
that's the job of inactivity monitor when using the OpenWire.
Unfortunately Stomp doesn't support that in version 1.0 and it is
something we want to add in the next version of the spec. Maybe
implementing something like that on the application level would help
in your case?
Cheers
--
Dejan Bosanac - http://twitter.com/dejanb
Open Source Integration - http://fusesource.com/
ActiveMQ in Action - http://www.manning.com/snyder/
Blog - http://www.nighttale.net
On Wed, Apr 14, 2010 at 5:41 PM, Josh Carlson <jcarl...@e-dialog.com
<mailto:jcarl...@e-dialog.com>> wrote:
Hmm. If a timeout was the solution to this problem how would you
be able to tell the difference between something being wrong and
the client just being slow.
I did an strace on the server and discovered how the timeout is
being used. As a parameter to poll
6805 10:31:15 poll([{fd=94, events=POLLIN|POLLERR}], 1, 60000
<unfinished ...>
6805 10:31:15 <... poll resumed> ) = 1 ([{fd=94,
revents=POLLIN}])
6805 10:31:15 recvfrom(94, "CONNECT\npasscode:...."..., 8192, 0,
NULL, NULL) = 39
6805 10:31:15 sendto(94, "CONNECTED\nsession:ID:mmq1-40144-"...,
53, 0, NULL, 0) = 53
6805 10:31:15 poll([{fd=94, events=POLLIN|POLLERR}], 1, 60000) =
1 ([{fd=94, revents=POLLIN}])
6805 10:31:15 recvfrom(94,
"SUBSCRIBE\nactivemq.prefetchSize:"..., 8192, 0, NULL, NULL) = 138
6805 10:31:15 sendto(94, "RECEIPT\nreceipt-id:39ef0e071a549"...,
55, 0, NULL, 0) = 55
6805 10:31:15 poll([{fd=94, events=POLLIN|POLLERR}], 1, 60000
<unfinished ...>
6805 10:32:15 <... poll resumed> ) = 0 (Timeout)
6805 10:32:15 poll([{fd=94, events=POLLIN|POLLERR}], 1, 60000
<unfinished ...>
6805 10:33:15 <... poll resumed> ) = 0 (Timeout)
6805 10:33:15 poll([{fd=94, events=POLLIN|POLLERR}], 1, 60000
<unfinished ...>
6805 10:34:15 <... poll resumed> ) = 0 (Timeout)
In the output above I stripped lines that were not operations
directly on the socket. The poll Timeouts continue on ... with
nothing in between.
[r...@mmq1 tmp]# lsof -p 6755 | grep mmq1
java 6755 root 85u IPv6 1036912
TCP mmq1.eng.e-dialog.com:61613
<http://mmq1.eng.e-dialog.com:61613> (LISTEN)
java 6755 root 92u IPv6 1038039
TCP mmq1.eng.e-dialog.com:61613->10.0.13.230:46542
<http://10.0.13.230:46542> (ESTABLISHED)
java 6755 root 94u IPv6 1036997
TCP mmq1.eng.e-dialog.com:61613->mmd2.eng.e-dialog.com:41743
<http://mmd2.eng.e-dialog.com:41743> (ESTABLISHED)
The connection to mmd2 is the host that is gone. The one to
10.0.13.230 is up and active. When I kill -9 the process on
10.0.13.230 I see this in the logs:
2010-04-13 17:13:55,322 | DEBUG | Transport failed:
java.io.EOFException |
org.apache.activemq.broker.TransportConnection.Transport |
ActiveMQ Transport: tcp:///10.0.13.230:45463
<http://10.0.13.230:45463>
java.io.EOFException
at java.io.DataInputStream.readByte(Unknown Source)
at
org.apache.activemq.transport.stomp.StompWireFormat.readLine(StompWireFormat.java:186)
at
org.apache.activemq.transport.stomp.StompWireFormat.unmarshal(StompWireFormat.java:94)
at
org.apache.activemq.transport.tcp.TcpTransport.readCommand(TcpTransport.java:211)
at
org.apache.activemq.transport.tcp.TcpTransport.doRun(TcpTransport.java:203)
at
org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:186)
at java.lang.Thread.run(Unknown Source)
2010-04-13 17:13:55,325 | DEBUG | Stopping connection:
/10.0.13.230:45463 <http://10.0.13.230:45463> |
org.apache.activemq.broker.TransportConnection | ActiveMQ Task
2010-04-13 17:13:55,325 | DEBUG | Stopping transport
tcp:///10.0.13.230:45463 <http://10.0.13.230:45463> |
org.apache.activemq.transport.tcp.TcpTransport | ActiveMQ Task
2010-04-13 17:13:55,326 | DEBUG | Stopped transport:
/10.0.13.230:45463 <http://10.0.13.230:45463> |
org.apache.activemq.broker.TransportConnection | ActiveMQ Task
2010-04-13 17:13:55,327 | DEBUG | Cleaning up connection
resources: /10.0.13.230:45463 <http://10.0.13.230:45463> |
org.apache.activemq.broker.TransportConnection | ActiveMQ Task
2010-04-13 17:13:55,327 | DEBUG | remove connection id:
ID:mmq1-58415-1271193024658-2:3 |
org.apache.activemq.broker.TransportConnection | ActiveMQ Task
2010-04-13 17:13:55,328 | DEBUG | masterb1 removing consumer:
ID:mmq1-58415-1271193024658-2:3:-1:1 for destination:
queue://Producer/TESTING/weight/three/ |
org.apache.activemq.broker.region.AbstractRegion | ActiveMQ Task
Which is what I want to happen when the host goes down.
It seems to be that something should be noticing that the
connection is really gone. Maybe this is more of a kernel issue.
I would think that when the poll is done that it would trigger
the connection to move from the ESTABLISHED state and get closed.
We are using Linux, kernel version 2.6.18, but I've seen this
same issue on a range of different 2.6 versions.
-Josh
On 04/14/2010 09:38 AM, Josh Carlson wrote:
Thanks Gary for the, as usual, helpful information.
It looks like the broker maybe suffering from exactly the
same problem
we encountered when implementing client-side failover. Namely
that when
the master broker went down a subsequent read on the socket
by the
client would hang (well actually take a very long time to
fail/timeout).
In that case our TCP connection was ESTABLISHED and looking
at the
broker I see the same thing after the client host goes away (the
connection is ESTABLISHED). We fixed this issue in our client
by setting
the socket option SO_RCVTIMEO on the connection to the broker.
I noted what the broker appears to do the same thing with the TCP
transport option soTimeout. It looks like when this is set it
winds up
as a call to java.net.Socket.setSoTimeout when the socket is
getting
initialized. I have not done any socket programming in Java
but my
assumption is that SO_TIMEOUT maps to both SO_RCVTIMEO and
SO_SNDTIMEO
in the C world.
I was hopeful with this option but when I set in in my
transport connector:
<transportConnector name="stomp"
uri="stomp://mmq1:61613?soTimeout=60000"/>
the timeout does not occur. I actually ran my test case about
15 hours
ago and I can still see that the broker still has an ESTABLISHED
connection to the dead client and has a message dispatched to it.
Am I miss understanding what soTimeout is for? I can see in
org.apache.activemq.transport.tcp.TcpTransport.initialiseSocket
that
setSoTimeout is getting called unconditionally. So what I'm
wondering is
if it is actually calling it with a 0 value despite the way I
set up my
transport connector. I suppose setting this to 0 would
explain why it
apparently never times out where in our client case it
eventually did
timeout (because we were not setting the option at all before).
On 04/14/2010 05:15 AM, Gary Tully wrote:
The re-dispatch is triggered by the tcp connection dying,
netstat can
help with the diagnosis here. Check the connection state
of the broker
port after the client host is rebooted, if the connection
is still
active, possibly in a timed_wait state, you may need to
configure some
additional timeout options on the broker side.
On 13 April 2010 19:43, Josh
Carlson<jcarl...@e-dialog.com <mailto:jcarl...@e-dialog.com>
<mailto:jcarl...@e-dialog.com
<mailto:jcarl...@e-dialog.com>>> wrote:
I am using client acknowledgements with a prefetch
size of 1 with
no message expiration policy. When a consumer
subscribes to a
queue I can see that the message gets dispatched
correctly. If the
process gets killed before retrieving and
acknowledging the
message I see the message getting re-dispatched
(correctly). I
expected this same behaviour if the host running the
process gets
rebooted or crashes. However, after reboot I can see
that the
message is stuck in the dispatched state to the
consumer that is
long gone. Is there a way that I can get messages
re-dispatched
when a host hosting consumer processes gets
re-booted? How does it
detect the case when a process dies (even with SIGKILL)?
I did notice that if I increase my prefetch size and
enqueue
another message after the reboot, that activemq will
re-dispatch
the original message. However with prefetch size
equal to one the
message never seems to get re-dispatched.
--
http://blog.garytully.com
Open Source Integration
http://fusesource.com
