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https://issues.apache.org/jira/browse/AMQ-4710?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16528317#comment-16528317
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Leon Barrett commented on AMQ-4710:
-----------------------------------
I ran into this issue also just now.
This breaks heartbeats in a number of clients, including the go and python
STOMP clients linked from [the cross-language client
page|http://activemq.apache.org/cross-language-clients.html]. It's really easy
to test–enable heartbeats, connect and stay idle for a heartbeat cycle, and the
client immediately has a heartbeat error.
I agree that [~elliotbc]'s proposal (send heartbeats at twice the frequency)
sounds best and simplest. It satisfies the STOMP spec ("the sender MUST send
new data over the network connection at least every {{<n>}} milliseconds") and
is quite simple to implement–basically a 3-line fix.
I have attached a patch that implements that strategy and adds a test for that
initial heartbeat issue. It would be great if this could be fixed–it would
really improve ActiveMQ's cross-language compatibility. Let me know if there's
anything I can do to help get this fix merged.
[^AMQ-4710-double-heartbeat-frequency.patch]
> The first heart-beat after a connection becomes idle isn't sent as quickly as
> it should be
> ------------------------------------------------------------------------------------------
>
> Key: AMQ-4710
> URL: https://issues.apache.org/jira/browse/AMQ-4710
> Project: ActiveMQ
> Issue Type: Bug
> Components: stomp
> Affects Versions: 5.8.0
> Reporter: Andy Wilkinson
> Assignee: Timothy Bish
> Priority: Major
> Fix For: 5.x
>
> Attachments: AMQ-4710-double-heartbeat-frequency.patch, amq-4710.diff
>
>
> After ActiveMQ sends a stomp frame, it may not send a heart-beat for up to
> almost 2x the negotiated interval.
> The following test should illustrate the problem:
> {code}
> import org.junit.Test;
> import static org.junit.Assert.*;
> public class ActiveMqHeartbeatTests {
> @Test
> public void heartbeats() throws Exception {
> BrokerService broker = createAndStartBroker();
> Socket socket = null;
> try {
> socket = new Socket("localhost", 61613);
> byte[] connectFrame =
> "CONNECT\nheart-beat:0,10000\naccept-version:1.2\n\n\0".getBytes();
> socket.getOutputStream().write(connectFrame);
> byte[] buffer = new byte[4096];
> long lastReadTime = System.currentTimeMillis();
> while (true) {
> int read = socket.getInputStream().read(buffer);
> byte[] frame = Arrays.copyOf(buffer, read);
> long now = System.currentTimeMillis();
> long timeSinceLastRead = now - lastReadTime;
> lastReadTime = now;
> System.out.println(new String(frame));
> System.out.println("Time since last read: " +
> timeSinceLastRead + "ms");
> if (timeSinceLastRead > 15000) {
> fail("Data not received for " +
> timeSinceLastRead + "ms");
> }
> }
> } finally {
> if (socket != null) {
> socket.close();
> }
> broker.stop();
> }
> }
> private BrokerService createAndStartBroker() throws Exception {
> BrokerService broker = new BrokerService();
> broker.addConnector("stomp://localhost:61613");
> broker.setStartAsync(false);
> broker.setDeleteAllMessagesOnStartup(true);
> broker.start();
> return broker;
> }
> }
> {code}
> For the initial read of the CONNECTED frame I see:
> {noformat}
> Time since last read: 49ms
> {noformat}
> However, it's then almost 20 seconds before a heart-beat's sent:
> {noformat}
> Time since last read: 19994ms
> {noformat}
> If I comment out the fail(…) line in the test, after the first heartbeat
> taking almost 20000ms to be sent, things settle down and a heartbeat's
> received every 10000ms.
> It looks like the write checker wakes up every 10000ms. The first time it
> wakes up, it notices that the CONNECTED frame was sent and does nothing. It
> then sleeps for a further 10000ms before checking again. As the CONNECTED
> frame was sent very early in the first 10000ms window, this leads to it
> taking almost 20000ms for the first heart-beat to be sent. From this point,
> as no further data frames are sent, the write checker wakes up and sends a
> heart-beat every 10000ms.
> In short, I don't think ActiveMQ is adhering to the requirement that "the
> sender MUST send new data over the network connection at least every <n>
> milliseconds".
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