[GitHub] [pulsar-client-go] zzzming commented on issue #770: AckID block calling goroutine

[GitBox <gi...@apache.org>]

zzzming commented on issue #770:
URL: https://github.com/apache/pulsar-client-go/issues/770#issuecomment-1164758611

   In partitionConsumer, there is an event loop (eventsCh) handles events asynchronously. However, blocking can still take place because of two reasons in the design.
   1. The `eventsCh` is a buffered channel at the size of 10. This is means sending to the channel will be blocked if the channel is full. On the surface, that is the reason this issue is observed.
   2. The event loop is processing events synchronously. It is the second `for` loop in the function runEventsLoop. The code looks like this block
   ```
   for {
   		for i := range pc.eventsCh {
   			switch v := i.(type) {
   			case *ackRequest:
   				pc.internalAck(v)
   			case *redeliveryRequest:
   				pc.internalRedeliver(v)
   			case *unsubscribeRequest:
   				pc.internalUnsubscribe(v)
   			case *getLastMsgIDRequest:
   				pc.internalGetLastMessageID(v)
   			case *seekRequest:
   				pc.internalSeek(v)
   			case *seekByTimeRequest:
   				pc.internalSeekByTime(v)
   			case *closeRequest:
   				pc.internalClose(v)
   				return
   			}
   		}
   ```
   
   There is no sufficient information here to diagnose which call has blocked. But at least 10 event processing were blocked.
   @wolfstudy What is your opinion we run these internal calls as a separate goroutine without blocking the event loops? Like
   ``` 
                     for i := range pc.eventsCh {
   			switch v := i.(type) {
   			case *ackRequest:
   				go pc.internalAck(v)
   			case *redeliveryRequest:
   				go pc.internalRedeliver(v)
   			case *unsubscribeRequest:
   				go pc.internalUnsubscribe(v)
   			case *getLastMsgIDRequest:
   				go pc.internalGetLastMessageID(v)
   ...
   ```


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