Georgi Danov created AMQ-4977:
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Summary: Memory leak in ConnectionStateTracker when browsing
non-empty queues
Key: AMQ-4977
URL: https://issues.apache.org/jira/browse/AMQ-4977
Project: ActiveMQ
Issue Type: Bug
Affects Versions: 5.9.0, 5.8.0, 5.7.0, 5.6.0
Reporter: Georgi Danov
Priority: Critical
I think I found case that is not handled by the fix AMQ-3316. We see memory
leaks connected to this bug and after good amount of headbanging I think the
problem is in how two methods work together - processMessagePull and trackBack.
The first one has this piece of code:
// leave a single instance in the cache
final String id = pull.getDestination() + "::" +
pull.getConsumerId();
messageCache.put(id.intern(), pull);
while the second one unconditionally increases the currentCacheSize -
regardless if the previous method added or replaced entry in the cache.
The situation where entries will be replaced (and not added) and the
currentCacheSize will grow very fast until it wraps around and becomes negative
is the following:
have some logic that frequently creates queue browser and iterates through all
the entries
have the queue most of the time with at least one message. The more messages in
the queue the faster currentCacheSize grows.
Here is log from reproducing the issue as a proof:
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 10000, 5 elements, pending scans:10, memory: 8951KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 20000, 10 elements, pending scans:10, memory: 10845KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 30000, 15 elements, pending scans:10, memory: 12645KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 40000, 20 elements, pending scans:10, memory: 10363KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 50000, 25 elements, pending scans:10, memory: 12169KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 60000, 30 elements, pending scans:10, memory: 9852KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 70000, 35 elements, pending scans:10, memory: 11657KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 80000, 40 elements, pending scans:10, memory: 9401KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 90000, 45 elements, pending scans:10, memory: 11222KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 100000, 50 elements, pending scans:10, memory: 13047KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 110000, 55 elements, pending scans:10, memory: 10767KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 120000, 60 elements, pending scans:10, memory: 12567KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 130000, 65 elements, pending scans:10, memory: 10256KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 138800, 67 elements, pending scans:10, memory: 12085KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 146800, 67 elements, pending scans:10, memory: 9745KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 154800, 67 elements, pending scans:10, memory: 11566KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 162800, 67 elements, pending scans:10, memory: 9225KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 170800, 67 elements, pending scans:10, memory: 11013KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 178800, 67 elements, pending scans:10, memory: 12812KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 186800, 67 elements, pending scans:10, memory: 10522KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 194800, 67 elements, pending scans:10, memory: 12328KB
2014-01-16 23:05:14 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 202800, 67 elements, pending scans:10, memory: 9999KB
2014-01-16 23:05:15 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 210800, 67 elements, pending scans:10, memory: 11805KB
2014-01-16 23:05:15 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 218800, 67 elements, pending scans:10, memory: 9496KB
2014-01-16 23:05:15 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 226800, 67 elements, pending scans:10, memory: 11316KB
2014-01-16 23:05:15 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 234800, 67 elements, pending scans:10, memory: 13100KB
2014-01-16 23:05:15 WARN ActiveMqMemoryLeakTest - MaxCacheSize: 131072,
currentCacheSize: 242800, 67 elements, pending scans:10, memory: 10754KB
One can see that the garbage collection works well (cache does not grow) but
the currentCacheSize keeps increasing
Unfortunately I cannot easily extract the original code and provide it. Hope
the explanation is clear enough. If you agree - this bug has to be re-opened
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