There's also another reason for pinging, and that's for the client toīe able to detect that the server or network has failed.Īs long as the client is receiving data from the server it will consider Server and how "dead" connection resources are cleaned up by the server. In the previous section we discussed how the client sends pings to the
LEFT 4 DEAD 2 CLIENT TIMED OUT CODE
This will enable you to pinpoint the error in your code andĬorrect it appropriately. Where you created the JMS connection / client session that you later did Note that the log will also tell you the exact line of your user code 20:14:43,244 WARNING The session you didn't close was created here:Īt .(DelegatingSession.java:83)Īt (YourClass.java:666)Īpache ActiveMQ Artemis will then close the connection / client session for you. Please make sure you close all ClientSessions explicitly before let Session): 20:14:43,244 WARNING I'm closing a ClientSession you left open. Using JMS the warning will involve a JMS connection not a client Time, and log a warning similar to the following in the logs (If you are If you fail to do so, Apache ActiveMQ Artemis will detect this at garbage collection Closing core sessions or JMS connections that you have failed to closeĪs previously discussed, it's important that all core client sessionsĪnd JMS connections are always closed explicitly in a finally block The default value for connection-ttl-override is -1 which means "do This can be done by specifying theĬonnection-ttl-override attribute in the server side configuration. TTL, you can override all values used by a global value set on the If you do not wish clients to be able to specify their own connection Time out the connection on the server side. A value of -1 for ConnectionTTL means the server will never The default value forĬonnection ttl on a "reliable" connection (e.g. The default value for connection ttl on an "unreliable" connection (e.g.Ī Netty connection) is 60000ms, i.e. The server side, you can specify it in the xml config, using the If you're deploying JMS connection factory instances direct into JNDI on
If you're using JMS, the connection TTL is defined by theĬonnectionTTL attribute on a ActiveMQConnectionFactory instance, or Then it will automatically close all the sessions on the server that If the serverĭoesn't receive any packets on a connection for the connection TTL time,
Periodically to prevent the server from closing it down. The client will automatically send "ping" packets Server will keep a connection alive in the absence of any data arrivingįrom the client. Basically, the TTL determines how long the "dead" server side resources too soon or this will prevent any clientįrom reconnecting, as it won't be able to find its old sessions on theĪpache ActiveMQ Artemis makes all of this configurable. Server can fail and then come back, allowing the client to reconnect.Īpache ActiveMQ Artemis supports client reconnection, so we don't want to clean up With the fact that sometimes the network between the client and the We have to balance the requirement for cleaning up dead client resources Running out of memory or other resources. Resource leak on the server and over time this result in the server If these were not removed they would cause a If this occurs then it can leave server side resources, like sessions, Sometimes clients just crash so they don't have a chance to clean up
Unfortunately users don't always write well behaved applications, and
JmsConnection = jmsConnectionFactory.createConnection() Sf = locator.createClientSessionFactory() Īnd here's an example of a well behaved JMS client application: Connection jmsConnection = null ĬonnectionFactory jmsConnectionFactory = ActiveMQJMSClient.createConnectionFactoryWithoutHA(.) Locator = ActiveMQClient.createServerLocatorWithoutHA(.) Session and session factory in a finally block: ServerLocator locator = null Here's an example of a well behaved core client application closing its Practice that it should close its resources in a controlled manner, Cleaning up Dead Connection Resources on the Serverīefore an Apache ActiveMQ Artemis client application exits it is considered good In this section we will discuss connection time-to-live (TTL) andĮxplain how Apache ActiveMQ Artemis deals with crashed clients and clients which haveĮxited without cleanly closing their resources. Message Redelivery and Undelivered MessagesĬlient Reconnection and Session Reattachment Understanding the Apache ActiveMQ Artemis Wildcard Syntax
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