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From Gordon Sim <g...@redhat.com>
Subject Re: Sender capacity in C++ client
Date Thu, 07 Jul 2011 08:20:36 GMT
On 07/07/2011 05:40 AM, Jiri Krutil wrote:
> What is the meaning of 'capacity' of a Sender in the C++ messaging
> client?

It is the maximum number of buffered messages held by the sender.

> Does the client maintain a reply buffer of sent messages or is this
> merely a limit for the number of in-doubt or unconfirmed messages?

Yes to both, the in-doubt messages are held in a buffer whose size is 
controlled by capacity. These are the messages that are replayed if 
reconnect is enabled. Messages are removed from the buffer once 
confirmation is received that they have been successfully transferred.

> Is this a client-only setting or does the broker see it as well?

It is client only.

> What happens if the Sender capacity is full and I attempt to send
> another message? Does the call block until some messages are confirmed
> by the broker?

Yes, the call will block until space is freed up by the broker 
confirming messages.

This can at present indirectly used to flow control the producer. The 
c++ broker will delay sending confirmations for messages above a 
configured threshold on a queue.

> What is the default capacity?

The default at present is 50.

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