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Posted to dev@qpid.apache.org by "Robbie Gemmell (JIRA)" <ji...@apache.org> on 2011/03/20 01:08:29 UTC
[jira] Updated: (QPID-3157) subscriptions 'removed' from a queue
subscription list are only marked deleted and not actually completely
removed from the list
[ https://issues.apache.org/jira/browse/QPID-3157?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Robbie Gemmell updated QPID-3157:
---------------------------------
Description:
subscriptions 'removed' from a queue subscription list are only marked deleted and not actually released from memory. As a result any memory in use by the now-closed subscription will not be released until the queue is deleted. This also holds the ServerSession in memory.
This issue compounded when the queue has a backlog of messages and consumers are created, used to recieve one message, and then closed. In this scenario the broker sends the client as many messages as it can prefetch, leading to creation of up to <prefetch size, default=500> MessageTransfer commands, all which are recorded in the ServerSession but then left retained as 'unprocessed' in the closed session. This results in an explosion in the number of MessageTransfer commands retained in memory as each message can have up to <prefetch size> MessageTransfer commands associated with it before it is eventually consumed by a client and all of thse will also be retained in memory. The last effect can be combated by restricting the preftech size (eg appending &maxprefetch='1' to the connection url).
was:subscriptions 'removed' from a queue subscription list are only marked deleted and not actually released from memory. As a reult any memory in use by the now-closed subscription will not be released until the queue is deleted.
Priority: Blocker (was: Critical)
> subscriptions 'removed' from a queue subscription list are only marked deleted and not actually completely removed from the list
> --------------------------------------------------------------------------------------------------------------------------------
>
> Key: QPID-3157
> URL: https://issues.apache.org/jira/browse/QPID-3157
> Project: Qpid
> Issue Type: Bug
> Components: Java Broker
> Affects Versions: 0.5, 0.6, 0.7, 0.8, 0.9, 0.10
> Reporter: Robbie Gemmell
> Priority: Blocker
> Fix For: 0.11
>
>
> subscriptions 'removed' from a queue subscription list are only marked deleted and not actually released from memory. As a result any memory in use by the now-closed subscription will not be released until the queue is deleted. This also holds the ServerSession in memory.
> This issue compounded when the queue has a backlog of messages and consumers are created, used to recieve one message, and then closed. In this scenario the broker sends the client as many messages as it can prefetch, leading to creation of up to <prefetch size, default=500> MessageTransfer commands, all which are recorded in the ServerSession but then left retained as 'unprocessed' in the closed session. This results in an explosion in the number of MessageTransfer commands retained in memory as each message can have up to <prefetch size> MessageTransfer commands associated with it before it is eventually consumed by a client and all of thse will also be retained in memory. The last effect can be combated by restricting the preftech size (eg appending &maxprefetch='1' to the connection url).
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