activemq 专业术语

Pending Queue Size ­ queue中还未发送至client的消息数，一般是消费者的处理速度慢，且本地的消息存储池已满（tcp://localhost:61616?jms.prefetchPolicy.all=预抓取得消息数（存储池），默认是1000）

 

persistent queues (default value: 1000)
non-persistent queues (default value: 1000)
persistent topics (default value: 100)
non-persistent topics (default value: Short.MAX_VALUE -1)

 
Dispatched Counter ­ queue中已经发给client，包括还没有确认的消息数量（ acknowledged）

 

Enqueue Counter 生产者已经发送到queue的消息数量
Dequeue Counter ­已经消费调的消息数量

 

值得注意的：

Consuming messages from a pool of consumers an be problematic due to prefetch. Unconsumed prefetched messages are only released when a consumer is closed, but with a pooled consumer the close is deferred (for reuse) till the consumer pool closes. This leaves prefetched messages unconsumed till the consumer is reused. This feature can be desirable from a performance perspective but it can lead to out-of-sequence messages when there is more than one consumer in the pool.
For this reason, the org.apache.activemq.pool.PooledConnectionFactory does not pool consumers. 
The problem is visible with the Spring DMLC when the cache level is set to CACHE_CONSUMER and there are multiple concurrent consumers.
One solution to this problem is to use a prefetch of 0 for a pooled consumer, in this way, it will poll for messages on each call toreceive(timeout).

 

另附:http://activemq.apache.org/faq.html 里面有常见的一些关于activemq的文章