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https://issues.apache.org/jira/browse/POOL-350?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16945183#comment-16945183
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Phil Steitz commented on POOL-350:
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How about adding two config parameters
reuseCapacityOnReturn
reuseCapacityOnMaintenance
Maybe with better names. The way it works now is reuseCapacity is called on
return only. I can see wanting to turn this off in some applications (though
it risks liveness problems). Having the option to have the evictor do it might
work for some workloads.
Another option is to make it more efficient. I played a little with
introducing a map of atomic ints maintaining waiter counts so you don't have to
walk the pool list and get the locks on the LBDs; but I could not demonstrate
better performance that way. Could be my benchmarks were misleading though and
that is another option here.
> Add option for not executing "hasBorrowWaiters()" while returning objects
> -------------------------------------------------------------------------
>
> Key: POOL-350
> URL: https://issues.apache.org/jira/browse/POOL-350
> Project: Commons Pool
> Issue Type: New Feature
> Affects Versions: 2.6.0
> Environment: h5. uname -a:
> Linux VMS26239 3.10.0-229.11.1.el7.x86_64 #1 SMP Thu Aug 6 01:06:18 UTC 2015
> x86_64 x86_64 x86_64 GNU/Linux
>
> *Java version:*
> java version "1.8.0_60"
> Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
> Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)
>
>
> Reporter: zhu chen
> Priority: Critical
> Labels: easyfix
>
> h2. Phenomena:
> I'm recently leveraging commons-pool as my Redis connection pool in my
> project, however, the pain is that when my system is dealing with over
> thousands of Redises, CPU load become such high. By checking JVM through
> JFR(FlightRecorder), it turned out the hot method was
> "{color:#FF0000}hasBorrowWaiters(){color}", which is invoked by
> "{color:#FF0000}returnObject(){color}" each time.
> That means the system will go through over *thousands*(the number will grow
> as well as my system) of keys after *each* object's *return*, what's worse,
> the program is running concurrently, which, obviously cause a huge CPU load.
>
> h2. Expect:
> I was wondering if we could add a config for optionally run this
> "hasBorrowWaiters()" each time when we return an object.
>
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