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https://issues.apache.org/jira/browse/KAFKA-385?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13435689#comment-13435689
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Joel Koshy commented on KAFKA-385:
----------------------------------
Jun had brought up one more problem - the factory method to getAndMaybePut
doesn't really
fix the problem of avoiding instantiation of objects if they are already
present in the Pool since the
anonymous function that I use needs to instantiate the object. I tweaked the
code to use lazy vals
and used logging to verify that each object in the Pool is instantiated only
once.
>From what I understand, it seems lazy val's implementation effectively uses a
>synchronized bitmap
to keep track of whether a particular val has been created or not. However, I'm
not so sure how it works
if the val involves a parameter. e.g., lazy val factory = new MyClass(param) as
opposed to
lazy val factory = new MyClass The concern is that scala may need to create
some internal wrapper
classes (at runtime). I tried disassembling the bytecode but did not want to
spend too much time on
it - so I thought I'd ask if anyone know details of how lazy vals work when the
actual instance is only
known at runtime?
> RequestPurgatory enhancements - expire/checkSatisfy issue; add jmx beans
> ------------------------------------------------------------------------
>
> Key: KAFKA-385
> URL: https://issues.apache.org/jira/browse/KAFKA-385
> Project: Kafka
> Issue Type: Bug
> Reporter: Joel Koshy
> Assignee: Joel Koshy
> Labels: bugs
> Fix For: 0.8
>
> Attachments: example_dashboard.jpg, graphite_explorer.jpg,
> KAFKA-385-v1.patch, KAFKA-385-v2.patch, KAFKA-385-v3.patch, KAFKA-385-v3.patch
>
>
> As discussed in KAFKA-353:
> 1 - There is potential for a client-side race condition in the
> implementations of expire and checkSatisfied. We can just synchronize on the
> DelayedItem.
> 2 - Would be good to add jmx beans to facilitate monitoring RequestPurgatory
> stats.
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