[teiid-issues] [JBoss JIRA] (TEIID-3106) BufferManager Cleaner consuming 90% of total CPU time
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https://issues.jboss.org/browse/TEIID-3106?page=com.atlassian.jira.plugin...
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Steven Hawkins commented on TEIID-3106:
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This strikes me as odd but there could be good reason for it.
I think the intention was to allow the gets from the lower level cache to be purged after
completely new entries, but a later change split the eviction queues into a two queue
system so it's not really necessary.
Do you think any specific info would be helpful ?
Perhaps some metrics on the eviction queues, such as the size. Are you still seeing that
removal and/or eviction not working for the entries or is it just that a lot of time is
being spent in removal? What jvm are you on? Older JREs have an issue with
ConcurrentSkipListMap scaling.
BufferManager Cleaner consuming 90% of total CPU time
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Key: TEIID-3106
URL: https://issues.jboss.org/browse/TEIID-3106
Project: Teiid
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: Query Engine
Affects Versions: 8.7
Environment: zOS
Reporter: Devesh Mishra
Assignee: Steven Hawkins
Labels: teiid-engine
Attachments: BufferManagerImpl.java, CacheKey_Loog.patch, cpu monitoring.docx,
in_local.docx, non_high_cpu.docx
BufferManager Cleaner thread is consuming almost all of the CPU utilized by the jboss
process. Thread dump shows following information.
3XMTHREADINFO "BufferManager Cleaner" J9VMThread:0x0000004C41CFEB00,
j9thread_t:0x0000004C52B85AE0, java/lang/Thread:0x000000481C036E20, state:CW, prio=5
3XMJAVALTHREAD (java/lang/Thread getId:0x76, isDaemon:true)
3XMTHREADINFO1 (native thread ID:0x3AEC2600, native priority:0x5, native
policy:UNKNOWN)
3XMHEAPALLOC Heap bytes allocated since last GC cycle=2609184 (0x27D020)
3XMTHREADINFO3 Java callstack:
4XESTACKTRACE at
java/util/concurrent/ConcurrentSkipListMap.doRemove(ConcurrentSkipListMap.java:1070(Compiled
Code))
4XESTACKTRACE at
java/util/concurrent/ConcurrentSkipListMap.remove(ConcurrentSkipListMap.java:1659(Compiled
Code))
4XESTACKTRACE at
org/teiid/common/buffer/impl/LrfuEvictionQueue.remove(LrfuEvictionQueue.java:60(Compiled
Code))
4XESTACKTRACE at
org/teiid/common/buffer/impl/BufferManagerImpl.doEvictions(BufferManagerImpl.java:854(Compiled
Code))
5XESTACKTRACE (entered lock:
org/teiid/common/buffer/CacheEntry@0x00000048393C2598, entry count: 1)
4XESTACKTRACE at
org/teiid/common/buffer/impl/BufferManagerImpl$Cleaner.run(BufferManagerImpl.java:108)
4XESTACKTRACE at java/util/TimerThread.mainLoop(Timer.java:555)
4XESTACKTRACE at java/util/TimerThread.run(Timer.java:505)
When we added log statements around the BufferManagerImpl.doEvictions() it loops through
the remove and firstEntry loop.
Forum discussion link : https://community.jboss.org/message/901792
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