[PROTON-905] Long-lived connections leak sessions and links

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: proton-0.9.1, proton-0.10
• Component/s: proton-c
• Labels: leak
• Assignee: Alan Conway
• Reporter: Ken Giusti
• Created: 10/Jun/15 13:21
• Updated: 17/Jul/18 09:33
• Resolved: 10/Jul/18 22:37

Description

I found this issue while debugging a crash dump of qpidd.

Long lived connections do not free its sessions/link.

This only applies when NOT using the event model. The version of qpidd I tested against (0.30) still uses the iterative model. Point to consider, I don't know why this is the case.

Details: I have a test script that opens a single connection, then continually creates sessions/links over that connection, sending one message before closing and freeing the sessions/links. See attached.

Over time the qpidd run time consumes all memory on the system and is killed by OOM. To be clear, I'm using drain to remove all sent messages - there is no message build up.

On debugging this, I'm finding thousands of session objects on the connections free sessions weakref list. Every one of those sessions has a refcount of one.

Once the connection is finalized, all session objects are freed. But until then, freed sessions continue to accumulate indefinitely.

Issue Links

• relates to: DISPATCH-1069 memory grows on a long-lived connection when links are opened and closed