[#DERBY-1704] Allow more concurrency in the lock manager

Derby

Allow more concurrency in the lock manager

Created: 16/Aug/06 12:29 PM Updated: 29/Jun/09 02:31 PM

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Component/s:

Services

Affects Version/s:

10.2.1.6

Fix Version/s:

10.3.1.4

Time Tracking:

Issue & Sub-Tasks

Issue Only

Not Specified

File Attachments:

File Name	Date Attached	Attached By	Size
cleanup1.diff	2007-01-19 01:35 PM	Knut Anders Hatlen	7 kB
cleanup1.stat	2007-01-19 01:35 PM	Knut Anders Hatlen	0.3 kB
cleanup1.v2.diff	2007-01-22 02:02 PM	Knut Anders Hatlen	8 kB
cleanup2.diff	2007-01-24 08:53 AM	Knut Anders Hatlen	2 kB
cleanup3.diff	2007-02-13 08:03 AM	Knut Anders Hatlen	6 kB
cleanup3.stat	2007-02-13 08:03 AM	Knut Anders Hatlen	0.2 kB
cleanup4.diff	2007-03-12 08:32 AM	Knut Anders Hatlen	0.6 kB
cleanup5.diff	2007-03-13 01:38 PM	Knut Anders Hatlen	5 kB
cleanup5.stat	2007-03-13 01:38 PM	Knut Anders Hatlen	0.2 kB
cleanup6.diff	2007-03-13 03:29 PM	Knut Anders Hatlen	2 kB
split-hashtables.diff	2006-08-16 12:36 PM	Knut Anders Hatlen	12 kB
split-hashtables.stat	2006-08-16 12:36 PM	Knut Anders Hatlen	0.3 kB

Image Attachments:

1. 1cpu.png
(3 kB)

2. 2cpu.png
(4 kB)

3. 8cpu.png
(3 kB)

Urgency:	Normal
Bug behavior facts:	Performance
Resolution Date:	25/May/07 06:58 AM

Sub-Tasks:

All

Open

1.	~~Reduce monitor contention in LockSet~~		Closed	Knut Anders Hatlen
2.	~~Reduce monitor contention in SinglePool~~		Closed	Knut Anders Hatlen

Description

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I have seen indications of severe monitor contention in SinglePool
(the current lock manager) when multiple threads access a Derby
database concurrently. When a thread wants to lock an object, it needs
to obtain the monitor for both SinglePool and LockSet (both of them
are global synchronization points). This leads to poor scalability.

We should investigate how to allow more concurrency in the lock
manager, and either extend SinglePool or implement a new manager.

All

Comments

Work Log

Change History

Subversion Commits

Sort Order:

Repository	Revision	Date	User	Message
ASF	#498999	Tue Jan 23 12:08:23 UTC 2007	kahatlen	~~DERBY-1704~~ (partial) Allow more concurrency in the lock manager * Made LockSet contain a HashMap instead of extending Hashtable. * Fixed some comments about MT/synchronization.
				Files Changed
				MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/LockTableVTI.java MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/SinglePool.java MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/LockSet.java MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/Deadlock.java

Repository	Revision	Date	User	Message
ASF	#499316	Wed Jan 24 08:50:00 UTC 2007	kahatlen	~~DERBY-1704~~ (partial) Allow more concurrency in the lock manager Removed some unused code.
				Files Changed
				MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/SinglePool.java MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/LockSet.java MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/Deadlock.java

Repository	Revision	Date	User	Message
ASF	#507428	Wed Feb 14 07:40:23 UTC 2007	kahatlen	~~DERBY-1704~~ (partial) Allow more concurrency in the lock manager Modified LockSpace so that it doesn't extend Hashtable.
				Files Changed
				MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/LockSpace.java MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/SinglePool.java

Repository	Revision	Date	User	Message
ASF	#517588	Tue Mar 13 08:33:40 UTC 2007	kahatlen	~~DERBY-1704~~: Allow more concurrency in the lock manager Simplified LockControl.popFrontWaiter().
				Files Changed
				MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/LockControl.java

Repository	Revision	Date	User	Message
ASF	#518052	Wed Mar 14 08:17:41 UTC 2007	kahatlen	~~DERBY-1704~~ (cleanup) * Remove unused imports * Make classes package private * Remove check for condition that is always true * Simplify parameter lists
				Files Changed
				MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/LockControl.java MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/Lock.java MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/ActiveLock.java

Repository	Revision	Date	User	Message
ASF	#518073	Wed Mar 14 08:51:00 UTC 2007	kahatlen	~~DERBY-1704~~ (cleanup) Remove unused Hashtable.
				Files Changed
				MODIFY /db/derby/code/trunk/java/engine/org/apache/derby/impl/services/locks/LockSet.java