Spring Batch - Not all records are being processed from MQ retrieval

Question

I am fairly new to Spring and Spring Batch, so feel free to ask any clarifying questions if you have any.

I am seeing an issue with Spring Batch that I cannot recreate in our test or local environments. We have a daily job that connects to Websphere MQ via JMS and retrieves a set of records. This job uses the out-of-the-box JMS ItemReader. We implement our own ItemProcessor, but it doesn't do anything special other than logging. There are no filters or processing that should affect incoming records.

The problem is that out of the 10,000+ daily records on MQ, only about 700 or so (the exact number is different each time) usually get logged in the ItemProcessor. All records are successfully pulled off the queue. The number of records logged is different each time and seems to have no pattern. By comparing the log files against the list of records in MQ, we can see that a seemingly random subset of records are being "processed" by our job. The first record might get picked up, then 50 are skipped, then 5 in a row, etc. And the pattern is different each time the job runs. No exceptions are logged either.

When running the same app in localhost and test using the same data set, all 10,000+ records are successfully retrieved and logged by the ItemProcessor. The job runs between 20 and 40 seconds in Production (also not constant), but in test and local it takes several minutes to complete (which obviously makes sense since it is handling so many more records).

So this is one of those tough issue to troubleshoot since we cannot recreate it. One idea is to implement our own ItemReader and add additional logging so that we can see if records are getting lost before the reader or after the reader - all we know now is that only a subset of records are being handled by the ItemProcessor. But even that will not solve our problem, and it will be somewhat timely to implement considering it is not even a solution.

Has anyone else seen an issue like this? Any possible ideas or troubleshooting suggestions would be greatly appreciated. Here are some of the jar version numbers we are using for reference.

• Spring - 3.0.5.RELEASE
• Spring Integration - 2.0.3.RELEASE
• Spring Batch - 2.1.7.RELEASE
• Active MQ - 5.4.2
• Websphere MQ - 7.0.1

Thanks in advance for your input.

EDIT: Per request, code for processor:

public SMSReminderRow process(Message message) throws Exception {

    SMSReminderRow retVal = new SMSReminderRow();
    LOGGER.debug("Converting JMS Message to ClaimNotification");
    ClaimNotification notification = createClaimNotificationFromMessage(message);

    retVal.setShortCode(BatchCommonUtils
            .parseShortCodeFromCorpEntCode(notification.getCorpEntCode()));
    retVal.setUuid(UUID.randomUUID().toString());
    retVal.setPhoneNumber(notification.getPhoneNumber());
    retVal.setMessageType(EventCode.SMS_CLAIMS_NOTIFY.toString());

    DCRContent content = tsContentHelper.getTSContent(Calendar
            .getInstance().getTime(),
            BatchCommonConstants.TS_TAG_CLAIMS_NOTIFY,
            BatchCommonConstants.TS_TAG_SMSTEXT_TYP);

    String claimsNotificationMessage = formatMessageToSend(content.getContent(),
            notification.getCorpEntCode());

    retVal.setMessageToSend(claimsNotificationMessage);
    retVal.setDateTimeToSend(TimeUtils
            .getGMTDateTimeStringForDate(new Date()));

    LOGGER.debug(
            "Finished processing claim notification for {}. Writing row to file.",
            notification.getPhoneNumber());
    return retVal;
}

JMS config:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
<bean id="claimsQueueConnectionFactory" class="org.springframework.jndi.JndiObjectFactoryBean">
    <property name="jndiName" value="jms/SMSClaimNotificationCF" />
    <property name="lookupOnStartup" value="true" />
    <property name="cache" value="true" />
    <property name="proxyInterface" value="javax.jms.ConnectionFactory" />
</bean>

<bean id="jmsDestinationResolver"
    class="org.springframework.jms.support.destination.DynamicDestinationResolver">
</bean>

<bean id="jmsJndiDestResolver" 
    class=" org.springframework.jms.support.destination.JndiDestinationResolver"/>  

<bean id="claimsJmsTemplate" class="org.springframework.jms.core.JmsTemplate">
    <property name="connectionFactory" ref="claimsQueueConnectionFactory" />
    <property name="defaultDestinationName" value="jms/SMSClaimNotificationQueue" />
    <property name="destinationResolver" ref="jmsJndiDestResolver" />
    <property name="pubSubDomain">
        <value>false</value>
    </property>
    <property name="receiveTimeout">
        <value>20000</value>
    </property>
</bean>

Answer 1

As a rule, MQ will NOT lose messages when properly configured. The question then is what does "properly configured" look like?

Generally, lost messages are caused by non-persistence or non-transactional GETs.

If non-persistent messages are traversing QMgr-to-QMgr channels and NPMSPEED(FAST) is set then MQ will not log errors if they are lost. That is what those options are intended to be used for so no error is expected.

Fix: Set NPMSPEED(NORMAL) on the QMgr-to-QMgr channel or make the messages persistent.

If the client is getting messages outside of syncpoint, messages can be lost. This is nothing to do with MQ specifically, it's just how messaging in general works. If you tell MQ to get a message destructively off the queue and it cannot deliver that message to the remote application then the only way for MQ to roll it back is if the message was retrieved under syncpoint.

Fix: Use a transacted session.

There are some additional notes, born out of experience.

• Everyone swears message persistence is set to what they think it is. But when I stop the application and inspect the messages manually it very often is not what is expected. It's easy to verify so don't assume.
• If a message is rolled back on the queue, it won't happen until MQ or TCP times out the orphan channel This can be up to 2 hours so tune the channel parms and TCP Keepalive to reduce that.
• Check MQ's error logs (the ones at the QMgr not the client) to look for messages about transactions rolling back.
• If you still cannot determine where the messages are going, try tracing with SupportPac MA0W. This trace runs as an exit and it is extremely configurable. You can trace all GET operations on a single queue and only that queue. The output is in human-readable form.

Answer 2

See http://activemq.apache.org/jmstemplate-gotchas.html .

There are issues using the JMSTemplate. I only ran into these issues when I upgraded my hardware and suddenly exposed a pre-existing race condition.

The short form is that by design and intent the JMS Template opens and closes the connection on every invocaton. It will not see messages older than its creation. In high volume and/or high throughput scenarios, it will fail to read some messages.