限制Mule的JDBC入站中的线程数

Question

I have a jdbc inbound endpoint that selects tens of thousands of records. Mule automatically spits them up and process each of them concurrently. The problem is, the process involves calling another service that cannot handle so many requests at the same time. Is there a way to limit the number of concurrent threads so that not that many requests happen at the same time? I am reading http://www.mulesoft.org/documentation/display/current/Configuring+a+Transport#ConfiguringaTransport-receiver but I cannot grasp how to do it. I tried:

<jdbc-ee:inbound-endpoint doc:name="db" connector-ref="testConnector" exchange-pattern="one-way" pollingFrequency="60000" queryTimeout="-1" queryKey="findAllPersonIds">
    <receiver-threading-profile maxThreadsActive="2" />
</jdbc-ee:inbound-endpoint>

But when I try to start it, Mule complains that 'receiver-threading-profile' isn't valid.

Answer 1

A JDBC inbound endpoint is a poller endpoint, which is backed by a single thread per Mule instance (or per cluster if you run EE).

The parallelism you're experiencing comes from the flow processing strategy, which by default has a threading profile that will use multiple concurrent threads.

You need to limit this parallelism for the flow that performs the remote HTTP invocation. You haven't shown your config so I can't tell if it's the same flow where the inbound JDBC endpoint is.

With the information you have provided, the best I can do is direct you to the reference documentation: http://www.mulesoft.org/documentation/display/current/Flow+Processing+Strategies

From this documentation, here is a flow that will use 500 concurrent threads:

<queued-asynchronous-processing-strategy name="allow500Threads"
                                         maxThreads="500"/>

<flow name="manyThreads" processingStrategy="allow500Threads">
  <vm:inbound-endpoint path="manyThreads" exchange-pattern="one-way"/>
  <vm:outbound-endpoint path="output" exchange-pattern="one-way"/>
</flow>