ActiveMQ needs tempUsage for recovery of persistent messages on startup?

[Martin C.]

Hi,

I a have a question regarding fileQueueCursor and systemUsage on
ActiveMQ 5.5.0: Below you see my configuration, which limits the
memory to 64MB, store usage to 10GB and tempUsage to 1GB.

I have a KahaDB with about 300000 messages, using 330MB in the kahadb
directory, all messages are persistent. If I start ActiveMQ, I see the
tmp_storage directory grow to 1GB, where it finally blocks and
recovery of the messages starts hanging:

[...]
DEBUG | default:memory: usage change from: 2% of available memory, to:
1% of available memory
DEBUG | default:memory:queue://local.queue.myqueue:memory: usage
change from: 1% of available memory, to: 0% of available memory
DEBUG | default:memory: usage change from: 1% of available memory, to:
0% of available memory
 INFO | cursor for queue://local.queue.myqueue has recovered 50000
messages. 15% complete
 INFO | cursor for queue://local.queue.myqueue has recovered 100000
messages. 31% complete
 INFO | cursor for queue://local.queue.myqueue has recovered 150000
messages. 47% complete
 INFO | cursor for queue://local.queue.myqueue has recovered 200000
messages. 62% complete

The memory usage goes up to around 75%, where it starts dropping down
to the 0% from the logfile above. This is where it keeps hanging, with
the tmp_storage directory at 1GB diskspace.

If I increase the tempUsage to 10GB, the startup works fine
(tmp_storage becomes about 1.4GB in this case). Can you explain to me,
why I need to increase tempUsage in order to restart my broker with a
lot of persistent messages left? As far as I understood the tempUsage
is for storing non-persistent messages, persistent messages should be
affected by storeUsage?

Thanks in advance!

Best regards,
Martin

PS: the relevant parts from my configuration

  <broker xmlns="http://activemq.apache.org/schema/core";
brokerName="localhost" dataDirectory="${activemq.base}/data"
    populateJMSXUserID="true" useJmx="true">

    <destinationPolicy>
      <policyMap>
        <policyEntries>
          <policyEntry topic=">" producerFlowControl="false"
gcInactiveDestinations="false" inactiveTimoutBeforeGC="60000">
              <vmCursor />
          </policyEntry>
          <policyEntry queue=">" producerFlowControl="false"
gcInactiveDestinations="false" inactiveTimoutBeforeGC="86400000">
            <deadLetterStrategy>
              <individualDeadLetterStrategy queuePrefix="DLQ."
useQueueForQueueMessages="true"
                processExpired="true" processNonPersistent="false" />
            </deadLetterStrategy>
            <pendingQueuePolicy>
              <fileQueueCursor />
            </pendingQueuePolicy>
          </policyEntry>
        </policyEntries>
      </policyMap>
    </destinationPolicy>

    <persistenceAdapter>
    <kahaDB directory="${activemq.base}/data/kahadb"
         checkForCorruptJournalFiles="true" checksumJournalFiles="true"
         concurrentStoreAndDispatchTopics="false"
         concurrentStoreAndDispatchQueues="false"
         />
    </persistenceAdapter>

    <systemUsage>
      <systemUsage sendFailIfNoSpace="true">
        <memoryUsage>
          <memoryUsage limit="64 mb" />
        </memoryUsage>
        <storeUsage>
          <storeUsage limit="10 gb" />
        </storeUsage>
        <tempUsage>
          <tempUsage limit="1 gb" />
        </tempUsage>
      </systemUsage>
    </systemUsage>
  </broker>