[pool] GenericObjectPool Evictor should be a TimerTask, not a Thread

• Key: POOL-56
• Type: Improvement
• Status: Resolved
• Resolution: Fixed
• Priority: Minor
• Assignee: Unassigned
• Reporter: Matt Bishop
• Affects Version/s: 1.2
• Fix Version/s: 1.3

Environment

Operating System: All
Platform: All

Description

Under most circumstances, an application will have one or two object pools, so
creating a new Evictor thread for each object is fine.

However, in the case of DBCP's PerUserDataSource class, this design is
unacceptable as it creates a thread for every distinct user that uses the data
source. In my case, our system has several thousand concurrent users, and as a
result, the system was attempting to create several thousand Evictor threads.

We fixed this by changing the Evictor from a Thread to a TimerTask which is
scheduled with the Timer class.

Comments

[Matt Bishop]

Created an attachment (id=16349)
Patch for GenericObjectPool.java

[Sandy McArthur (from Bugzilla import)]

Created an attachment (id=17671)
GenericObjectPools-TimerTask.patch

Updated and improved patch that applies to both GenericObjectPool and
GenericKeyedObjectPool. This patch is basicly the previously submitted one but:

• applies to current SVN
• Makes the java.util.Timer a daemon thread
• Also patches GenericKeyedObjectPool
• Shares the same Timer instance between the two pool types.

Committed. Many thanks.

Robert