[jboss-jira] [JBoss JIRA] Resolved: (EJBTHREE-1703) SLSB pooling statistics misleading when using ThreadLocalPool

[Carlo de Wolf (JIRA)]

     [ https://jira.jboss.org/jira/browse/EJBTHREE-1703?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Carlo de Wolf resolved EJBTHREE-1703.
-------------------------------------

    Fix Version/s: 1.1.11
       Resolution: Done


I've changed maxSize to dynamically adjust according to the number of threads using the ThreadlocalPool. Note that a reentrance means an extra addition to maxSize for the duration of the call. Or in other words: maxSize = createCount - removeCount.
This means that the equation: inUse = maxSize - availableCount will be valid from now on.

Initially maxSize and availableCount are 0 until the first call reaches the SLSB. Then maxSize becomes 1. AvailableCount will become 1 after the call finishes. Off course both values are bogus in relation to the ThreadlocalPool, because in actuality it can create an infinite amount of instances to service reentrant calls and other threads.

Again the real maximum size of the ThreadlocalPool is governed by the amount of threads calling upon the SLSB. If this is an unreasonable large number or the calls are coming from a thread factory instead of a thread pool, then StrictMaxPool must be used instead.

> SLSB pooling statistics misleading when using ThreadLocalPool
> -------------------------------------------------------------
>
>                 Key: EJBTHREE-1703
>                 URL: https://jira.jboss.org/jira/browse/EJBTHREE-1703
>             Project: EJB 3.0
>          Issue Type: Bug
>          Components: pool
>    Affects Versions: AS 4.2.3.GA, 1.0.0-GA
>            Reporter: Galder Zamarreno
>            Assignee: Carlo de Wolf
>            Priority: Critical
>             Fix For: 1.1.11
>
>
> SLSB pooling statistics are hugely misleading when using default ThreadLocalPool:
> "The default pooling strategy used by EJB3 SLSBs is a ThreadLocalPool whose maximum is not really 
> quantifiable. The maximum is the maximum number of concurrent threads talking to that EJB3 SLSB 
> that the system can allocate. So, the MaxSize that you see in that JMX view is bogus at least for its 
> current definition of maximum.
> MaxSize - AvailableCount will give you the number of EJB3 SLSBs currently in use, in your case, 0. Again, 
> the meaning of AvailableCount for this pool strategy is not precise.
> CreateCount does represent the number of EJB3 SLSBs that have been created.
> CurrentSize is a bit more complicated to explain. For each thread that uses an EJB3 SLSBs, thread local 
> pool maintains a pool per each thread where there's an instance active in case it's needed again. So, 
> CurrentSize indicates how many of these active instances there are, which assuming that each thread 
> uses only one instance of the bean, matches the number of instances that have been created."
> Example:
> AvailableCount 	int 	R 	30 	MBean Attribute.
> MaxSize 	                int 	R 	30 	MBean Attribute.
> StateString 	        java.lang.String 	R 	Started 	MBean Attribute.
> State 	                int 	R 	3 	MBean Attribute.
> CurrentSize 	        int 	R 	165 	MBean Attribute.
> CreateCount 	        int 	R 	165 	MBean Attribute.
> RemoveCount 	        int 	R 	0 	MBean Attribute.

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