How to guarantee message processing with Spring Integration MQTT Inbound Adapter - spring

Question

We are consuming messages from a HiveMQ MQTT Broker and process the data with spring integration. As the last processing step it is common for us to execute an update/insert statement on a relational database using an int-jpa:outbound-channel-adapter.
Let's consider a situation where the database connection is lost but mqtt messages are still consumed by the inbound mqtt adataper. Currently we lose these messages as we are not handling the failed database operations.
How should we handle the messages if the database connection is currently not available?
Should we implement a Message Store backed by another highly available database which is persisting messages from spring integration?
Should we implement a retry advice and periodically retry database operations?
As our starting point we tried to implement the retry advice with the following spring-context.xml. As a result the message was retried once and then an exception occured as it is not able to perform the database operation. No further retry was executed after the exception occurred.
<?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:int="http://www.springframework.org/schema/integration"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:int-jpa="http://www.springframework.org/schema/integration/jpa"
xmlns:task="http://www.springframework.org/schema/task"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
http://www.springframework.org/schema/integration/jpa http://www.springframework.org/schema/integration/jpa/spring-integration-jpa.xsd
http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.0.xsd">
<int:channel id="mqttInputChannel" />
<!-- MQTT INBOUND ADAPTER IS CONFIGURED IN JAVA -->
<int-jpa:outbound-channel-adapter
channel="mqttInputChannel"
flush-size=""
entity-class="com.iot.db.DefaultBean"
persist-mode="PERSIST"
entity-manager-factory="entityManagerFactory">
<int-jpa:transactional transaction-manager="transactionManager" />
<int-jpa:request-handler-advice-chain>
<ref bean="retryAdvice" />
</int-jpa:request-handler-advice-chain>
</int-jpa:outbound-channel-adapter>
<int:handler-retry-advice id="retryAdvice" />
</beans>
Another approach was to back up the messages via a message store but we weren't able to bind the message store to the jpa adapters transaction. Here is the corresponding spring-context.xml file with the message store:
<?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:int="http://www.springframework.org/schema/integration"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:int-jpa="http://www.springframework.org/schema/integration/jpa"
xmlns:task="http://www.springframework.org/schema/task"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/integration
http://www.springframework.org/schema/integration/spring-integration.xsd
http://www.springframework.org/schema/integration/jpa
http://www.springframework.org/schema/integration/jpa/spring-integration-jpa.xsd
http://www.springframework.org/schema/task
http://www.springframework.org/schema/task/spring-task-3.0.xsd">
<int:channel id="mqttInputChannel">
<int:queue message-store="messageStore" />
</int:channel>
<bean
id="messageStore"
class="org.springframework.integration.jdbc.store.JdbcChannelMessageStore">
<property
name="dataSource"
ref="dataSource" />
<property
name="channelMessageStoreQueryProvider"
ref="queryProvider" />
</bean>
<bean
id="queryProvider"
class="org.springframework.integration.jdbc.store.channel.H2ChannelMessageStoreQueryProvider" />
<!-- MQTT INBOUND ADAPTER IS CONFIGURED IN JAVA -->
<int-jpa:outbound-channel-adapter
channel="mqttInputChannel"
flush-size=""
entity-class="com.iot.db.DefaultBean"
persist-mode="PERSIST"
entity-manager-factory="entityManagerFactory">
<int-jpa:transactional transaction-manager="transactionManager" />
<int-jpa:request-handler-advice-chain>
<ref bean="retryAdvice" />
</int-jpa:request-handler-advice-chain>
</int-jpa:outbound-channel-adapter>
<int:handler-retry-advice id="retryAdvice" />
</beans>
Are there any best practices or well known pattern how to handle this situation?
thanks in advance