5/7/2023 0 Comments Dead letter queueThe monitor is in the operations view, in the section Manage Locks. Monitor Message Locks in Manage Lock MonitorĪs soon as a message is processed by the JMS sender adapter, a processing lock for this particular message is shown in the Message Locks monitor. To check whether messages have been removed from processing and moved to the dead letter queue, you can use the monitoring tools provided by Cloud Integration. Messages that fail because of an error during processing, do not go to the dead letter queue, but either stay in the normal processing (with a defined retry interval) or are removed from JMS (if configured in explicit retry modeling). The dead letter queue is only used for messages that could no longer be processed anymore because of a node crash. The dead letter queue configuration is not connected to the configuration of explicit retry handling described in the blog Configure Asynchronous Messaging with Retry Using JMS Adapter. You will then get the latest version.ĭead Letter Queue Versus Explicit Retry Configuration To find out the version choose the Technical Information icon in the channel. If you want to use the dead letter handling option, delete the sender channel and add it new from the palette. If you open an old integration flow, the Dead-Letter Queue setting might not be available because the version of the JMS adapter is too old. Checkbox Not Available – JMS Adapter Version Too Old Unfortunately not all sender adapters support the size check yet. The recommended configuration would be to configure the size check in the used sender adapter and with this configuration reject large messages to avoid that a large message can cause an out-of-memory. This is because the Dead-Letter Queue handling is based on the database and the database does not scale as good as JMS.įor high-load scenarios or if you are sure that only small messages will be processed in your scenario, you should deselect the checkbox to improve the performance, but do keep the risk of an outage in mind. This impact is even higher if you run high-load scenarios. The Dead-Letter Queue handling is a performance intensive operation, so you should expect a significant impact on the performance. The number of retries is not configurable. The checkbox, Dead-Letter Queue, for activating the dead letter queue is available on the Connection tab. The checkbox is selected by default, meaning that dead letter handling is active. After the second retry of a message that could not be completed because of a node crash, this message is moved to a dead letter queue and not processed any further. In the JMS sender adapter, the dead letter queue can be configured as of JMS adapter version 1.1. Configure Dead Letter Handling in JMS Sender Channel The blog Configure Asynchronous Messaging with Retry using JMS Adapter describes in detail how to setup asynchronous scenarios using the JMS adapter. Prerequisite: Broker Provisioning and Setup of JMS Scenario Manual action is necessary to restart or delete such messages. After that the message is taken out of processing and stored in a dead letter queue. To avoid this situation, messages where processing stopped unexpectedly, are retried only twice. The node restart would try to process the message again and again, leading to complete node unavailability. But in the outbound flow, the message may cause the problem described above: The node fails due to lack of memory, Cloud Platform restarts the node, the message is polled again from the queue and therefore causing another out-of-memory error. If such messages are processed in an asynchronously decoupled scenario using JMS, the message is stored in the JMS queue via the inbound flow, where there are normally no memory consuming conversions. Some messages, (usually large messages), received in the cloud integration system have the potential to lead to an out-of-memory error in the worker node, because processing the message requires too much memory. Dead Letter Handling in JMS Sender Adapter Dead letter handling in the JMS sender adapter is available for SAP Cloud Integration customers with an Enterprise Edition license. It describes the feature, when to use it, and how to monitor it. This blog describes the Dead Letter Queue option in the JMS sender adapter.
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