Hi,
In my application using the current trunk version, I was finding that my
queue subscriptions had huge pending message cursors sizes (> 70,000 and
growing) - essentially they were equal to enqueueCounter -
dispatchCounter which I could see from JMX.
It seems like a simple optimisation could be to remove a node from the
cursor if has been dropped when we call dispatchPending(). This made a
gigantic difference in speed, since the broker wasn't iterating over a
huge number of dropped messages, and locks were held for a shorter
period of time. Not to mention, less memory and CPU will be consumed by
the broker.
Here is the patch below - I don't know if it is safe in general, but it
seemed to work fine for me.
Cheers,
David
Index:
activemq-core/src/main/java/org/apache/activemq/broker/region/PrefetchSubscription.java
===================================================================
---
activemq-core/src/main/java/org/apache/activemq/broker/region/PrefetchSubscription.java
(revision 618650)
+++
activemq-core/src/main/java/org/apache/activemq/broker/region/PrefetchSubscription.java
(working copy)
@@ -453,7 +461,11 @@
if (node == null) {
break;
}
- if (canDispatch(node)) {
+ else if (((QueueMessageReference)node).isDropped())
+ {
+ pending.remove();
+ }
+ else if (canDispatch(node)) {
pending.remove();
// Message may have been sitting in
the pending
// list a while waiting for the
consumer to ak the message.
