Messages are not processed one after another - wso2

Question

I have an Inboundendpoint that connects to IBM MQ and reads messages periodically. I need to process messages one after the other. I need to wait until one message is fully consumed. But the messages are not always consumed sequentially. I have set the sequential flag to true. Here is a simplified version of my sequences.
<inboundEndpoint name="INBOUND_MQ_CONSUMER" onError="SEQ_MQ_ERROR" protocol="jms" sequence="SEQ_MQ_Process" suspend="false" xmlns=http://ws.apache.org/ns/synapse>
<parameters>
<parameter name="interval">1000</parameter>
<parameter name="sequential">true</parameter>
<parameter name="coordination">true</parameter>
<parameter name="transport.jms.Destination">$SYSTEM:mq_in_queue</parameter>
<parameter name="transport.jms.CacheLevel">3</parameter>
<parameter name="transport.jms.ConnectionFactoryJNDIName">$SYSTEM:mq_in_connection_factory</parameter>
<parameter name="java.naming.factory.initial">com.sun.jndi.fscontext.RefFSContextFactory</parameter>
<parameter name="java.naming.provider.url">$SYSTEM:PATH</parameter>
<parameter name="transport.jms.UserName">$SYSTEM:MQ_USER</parameter>
<parameter name="transport.jms.SessionAcknowledgement">AUTO_ACKNOWLEDGE</parameter>
<parameter name="transport.jms.Password">$SYSTEM:MQ_PASS</parameter>
<parameter name="transport.jms.SessionTransacted">false</parameter>
<parameter name="transport.jms.ConnectionFactoryType">queue</parameter>
<parameter name="transport.jms.ContentType">application/xml</parameter>
<parameter name="transport.jms.SharedSubscription">false</parameter>
<parameter name="transport.jms.ResetConnectionOnPollingSuspension">false</parameter>
</parameters>
</inboundEndpoint>
<sequence name="SEQ_MQ_Process" trace="disable" xmlns="http://ws.apache.org/ns/synapse">
<log level="full">
<property name="Received Message" value="MQ1872"/>
</log>
<payloadFactory media-type="xml">
<format>
<inline xmlns=""/>
</format>
<args/>
</payloadFactory>
<call>
<endpoint>
<http method="post" uri-template="http://something">
<suspendOnFailure>
<initialDuration>-1</initialDuration>
<progressionFactor>-1</progressionFactor>
<maximumDuration>0</maximumDuration>
</suspendOnFailure>
<markForSuspension>
<retriesBeforeSuspension>0</retriesBeforeSuspension>
</markForSuspension>
</http>
</endpoint>
</call>
<log level="full">
<property name="Processed Message" value="MQ1872"/>
</log>
</sequence>
Appreciate your help.

Answer 1

This could be a result of the non-blocking calls you are making. So simply Change your call mediators to blocking-mode.
<call blocking="true">
<endpoint>
<http method="post" uri-template="http://something">
<suspendOnFailure>
<initialDuration>-1</initialDuration>
<progressionFactor>-1</progressionFactor>
<maximumDuration>0</maximumDuration>
</suspendOnFailure>
<markForSuspension>
<retriesBeforeSuspension>0</retriesBeforeSuspension>
</markForSuspension>
</http>
</endpoint>
</call>