Ignite Realtime: XMPPConnection memory leak ...

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5 Replies Last post: May 17, 2008 8:16 AM by josh-parity

kflorian

4 posts since
Mar 12, 2008

Mar 14, 2008 4:49 AM

XMPPConnection memory leak

Hi all!

I'm facing memory issues with Smack API version 3.0.4:

About
10% of my XMPPConnections (and related objects) aren't
garbage-collected after disconnecting and setting the reference to null; not even by a forced collection.

I've
done some extensive testing using a memory profiler, which shows that
all of my objects (which open and disconnect the XMPPConnection) are
propperly garbage-collected - it's only org.jivesoftware objects
remaining in memory. I also made absolutely sure that
connection.disconnect() will be called on all connections before
releaseing them.

According to the memory-profiler, the
XMPPConnection objects remaining in memory are still referenced from
PrivacyListManager, ServiceDiscoveryManager and MultiUserChat$1$1 (?)
objects.

It seems that the Java garbage collection (java version
1.5.0_09) is having problems with collection large sets of objects
containting circular references.

Maybe setting some of these references to null in XMPPConnection.disconnect() would help?

Thanks for any feedback!

Florian Kirchmeir

kflorian

4 posts since
Mar 12, 2008

Mar 14, 2008 4:59 AM

in response to: kflorian

Re: XMPPConnection memory leak

PS: Objects still referenced by the XMPPConnection are:
socket, accountManager, chatManager, configuration and saslAuthentication (and some String values).
At least the accountManager, chatManager and saslAuthentication objects contain back-references to the containing XMPPConnection object.
Might be worthwhile to release them on a disconnect() ?

Best regards,
Florian Kirchmeir

kflorian

4 posts since
Mar 12, 2008

Mar 14, 2008 8:11 AM

in response to: kflorian

Re: XMPPConnection memory leak

Hi all!

I think I have found the problem in the Smack source:

Both PrivacyListManager and ServiceDiscoveryManager are holding a static Map of instances, using the XMPPConnection object as map key. New instances register a ConnectionListener with the connection, using the connectionClosed() callback to remove the instance (and the XMPPConnection object) from the static Map when the connection closes normally.

However, if the connection is closed on error, the call to the connectionClosedOnError() callback is ignored and the XMPPConnection object along with the associated Manager instance will never be removed from the static Map, and thus cannot be garbage collected.

A similar problem is found in the MultiUserChat class, that also ignores connectionClosedOnError() to do propper cleanup.

The attached patch seems to resolve the problem for me.
Any comments?

Best regards,
Florian Kirchmeir

Attachments:

connectionClosedOnError.patch (1.9 K)

kflorian

4 posts since
Mar 12, 2008

Mar 30, 2008 11:35 AM

in response to: kflorian

Re: XMPPConnection memory leak

Hi!

Any statement regarding this from "official" side?
Any chance my patch will find it's way into the next release?

I'd like to open a JIRA ticket reagarding this, but JIRA access seams to be read-only, even after logging in?!

Thanks for any feedback!

Florian Kirchmeir

josh-parity

9 posts since
Mar 24, 2008

May 17, 2008 7:49 AM

in response to: kflorian

Re: XMPPConnection memory leak

I think I'm having this issue. A long running Java application server with a MultiUserChat.

josh-parity

9 posts since
Mar 24, 2008

May 17, 2008 8:16 AM

in response to: josh-parity

Re: XMPPConnection memory leak

The closest JIRA I can find is: http://www.igniterealtime.org/issues/browse/SMACK-129

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