[teiid-issues] [JBoss JIRA] (TEIID-3106) BufferManager Cleaner consuming 90% of total CPU time

[Devesh Mishra (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-3106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12998008#comment-12998008 ] 

Devesh Mishra commented on TEIID-3106:
--------------------------------------

Hi Steve, I could not get the profiler run today (some technical glitch with my system probably). We have added log statements in CacheKey constructor to check if anything is going negative but did not see high CPU after that. I shall post further details tomorrow. Attaching the logging patch. 

> BufferManager Cleaner consuming 90% of total CPU time
> -----------------------------------------------------
>
>                 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
>
>
>  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 at 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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