[#POOL-135] _numActive > _maxActive under load

Commons Pool

_numActive > _maxActive under load

Created: 13/May/09 10:38 PM Updated: 19/Jun/09 04:10 PM

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Component/s:

None

Affects Version/s:

1.4

Fix Version/s:

1.5

Time Tracking:

Not Specified

Resolution Date:

13/May/09 10:48 PM

Description

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Whilst investigating other POOL issues, I noticed that _numActive can be > _maxActive when under load. Test case and fix to follow.

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Repository	Revision	Date	User	Message
ASF	#774574	Wed May 13 22:43:34 UTC 2009	markt	Add test case for ~~POOL-135~~. There is a timing element so this may not fail on all machines.
				Files Changed
				MODIFY /commons/proper/pool/trunk/src/test/org/apache/commons/pool/impl/TestGenericObjectPool.java

Repository	Revision	Date	User	Message
ASF	#774576	Wed May 13 22:44:48 UTC 2009	markt	Fix ~~POOL-135~~ for GOP.
				Files Changed
				MODIFY /commons/proper/pool/trunk/src/java/org/apache/commons/pool/impl/GenericObjectPool.java

Repository	Revision	Date	User	Message
ASF	#774579	Wed May 13 22:48:28 UTC 2009	markt	Fix ~~POOL-135~~ for GKOP.
				Files Changed
				MODIFY /commons/proper/pool/trunk/src/java/org/apache/commons/pool/impl/GenericKeyedObjectPool.java

Mark Thomas made changes - 13/May/09 10:48 PM

Field	Original Value	New Value
Resolution		Fixed [ 1 ]
Fix Version/s		1.5 [ 12312915 ]
Status	Open [ 1 ]	Resolved [ 5 ]

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Mark Thomas added a comment - 14/May/09 06:35 AM

The issue here is that addobjectToPool() returns an object to the pool and that another thread can borrow the newly returned object before _numActive is decremented. This can lead to _numActive > _maxActive although the real _numActive is <= _maxActive.

The fix ensures that when an object is returned to the pool, _numActive is decremented in the same sync block.

Repository	Revision	Date	User	Message
ASF	#774668	Thu May 14 07:34:57 UTC 2009	markt	Correct patch for ~~POOL-135~~. Only decrement _numActive when flag is set
				Files Changed
				MODIFY /commons/proper/pool/trunk/src/java/org/apache/commons/pool/impl/GenericKeyedObjectPool.java MODIFY /commons/proper/pool/trunk/src/java/org/apache/commons/pool/impl/GenericObjectPool.java

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Phil Steitz added a comment - 19/Jun/09 04:10 PM

Fixed in 1.5 release.

Phil Steitz made changes - 19/Jun/09 04:10 PM

Status

Resolved [ 5 ]

Closed [ 6 ]