[jira] [Comment Edited] (AMQ-5379) AMQP - allow setting prefetch size

["Robbie Gemmell (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/AMQ-5379?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14171203#comment-14171203 ] 

Robbie Gemmell edited comment on AMQ-5379 at 10/14/14 4:50 PM:
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Separately, the consumer prefetching has some issues from an AMQP perspective, possibly due to a bit of a mismatch between how the internal consumer prefetch handling of the broker works (being set to a particular size window initially), and how the explicit handling of credit in AMQP 1.0 works (consumers explicitly grant/retract credit for the server to use to send messages, as and when appropriate to satisfy the consumer clients needs).

>From an AMQP perspective, a consumer can attach without any credit initiall, then grant it later when it is deemed appropriate to receive messages, and also retract it to ensure it doesnt get any messages during a period when it doesnt want any. These behaviours could be combined to implement 0-prefetch synchronous recieve for example. Currently it would seem that due to the default prefetch value the broker may send messages to the client in cases where it hasnt yet 'asked' (provided any credit) for them, or in cases where it has asked not to get any more until further notice, which could cause problems. It is possible that Proton will handlethis, by buffering all the messages that there is not credit to send, which in itself could cause problems later or lead to some interesting memory usage.


was (Author: gemmellr):
Separately, the consumer prefetching has some issues from an AMQP perspective, possibly due to a bit of a mismatch between how the internal consumer prefetch handling of the broker works (being set to a particular size window initially), and how the explicit handling of credit in AMQP 1.0 works (consumers explicitly grant/retract credit for the server to use to send messages, as and when appropriate to satisfy the consumer clients needs).

>From an AMQP perspective, a consumer can attach without any credit initiall, then grant it later when it is deemed appropriate to receive messages, and also retract it to ensure it doesnt get any messages during a period when it doesnt want any. These behaviours could be combined to implement 0-prefetch synchronous recieve for example. Currently it would seem that due to the default prefetch value the broker may send messages to the client in cases where it hasnt yet 'asked' (provided any credit) for them, or in cases where it has asked not to get any more until further notice, which could cause problems.

> AMQP - allow setting prefetch size
> ----------------------------------
>
>                 Key: AMQ-5379
>                 URL: https://issues.apache.org/jira/browse/AMQ-5379
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: AMQP
>    Affects Versions: 5.10.0
>            Reporter: Dejan Bosanac
>            Assignee: Dejan Bosanac
>             Fix For: 5.11.0
>
>
> Currently the prefetch size is hardcoded to the value of 100



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