Lars:
Can you summarize your findings on
https://issues.apache.org/jira/browse/HBASE-4874 ?

Thanks

On Fri, Nov 25, 2011 at 9:06 PM, lars hofhansl <[email protected]> wrote:

> Here is something that will boggle your mind:
> After you ran TestHCM often enough it will hang until you move your mouse
> around!
>
> No joke... But what sounds like an impossibility is actually related to
> the use of SecureRandom.
> SecureRandom uses /dev/random on Linux and that gathers entropy from
> system events
> such as network activity, disk activity, keyboard activity, mouse
> movement, etc.
> If not enough the entropy is available /dev/random will block until enough
> entropy is gathered!
>
> When I add this to the command line (via pom.xml) TestHCM never hangs:
> "-Djava.security.egd=file:/dev/./urandom"
>
> (note that -Djava.security.egd=file:/dev/urandom does not work for some
> reason on JDK 1.5 or newer,  the extra ./ is needed)
>
>
> This instructs the JDK use /dev/urandom for SecureRandom, which unlike
> /dev/random will never block, but if not enough
> entropy exists it will generate random numbers of lesser quality... But
> for tests we don't care.
>
>
> That explains why tests only time out sometimes... when the system happens
> to run out of entropy bits when a secure random
> is used.
>
> -- Lars
>
>
> ________________________________
> From: Stack <[email protected]>
> To: [email protected]
> Cc: lars hofhansl <[email protected]>
> Sent: Friday, November 25, 2011 7:14 PM
> Subject: Re: Status of 0.92RC
>
> On Fri, Nov 25, 2011 at 6:16 PM, Ted Yu <[email protected]> wrote:
> > I then looped TestHCM 4 times and there was no test failure.
> >
>
> Its fine on mac.  On ubuntu:
>
>
> -------------------------------------------------------------------------------
> Test set: org.apache.hadoop.hbase.client.TestHCM
>
> -------------------------------------------------------------------------------
> Tests run: 5, Failures: 1, Errors: 0, Skipped: 0, Time elapsed:
> 757.578 sec <<< FAILURE!
> testClosing(org.apache.hadoop.hbase.client.TestHCM)  Time elapsed:
> 35.34 sec  <<< FAILURE!
> java.lang.AssertionError
>         at org.junit.Assert.fail(Assert.java:92)
>         at org.junit.Assert.assertTrue(Assert.java:43)
>         at org.junit.Assert.assertFalse(Assert.java:68)
>         at org.junit.Assert.assertFalse(Assert.java:79)
>         at
> org.apache.hadoop.hbase.client.TestHCM.testClosing(TestHCM.java:221)
>         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>
> ....
>
> Line numbers are off because I'm messing.  Its saying connection 1 is
> closed if I test it just after creating it.
>
> St.Ack
>
> > On Fri, Nov 25, 2011 at 5:39 PM, Ted Yu <[email protected]> wrote:
> >
> >> I looped TestHCM#testClosing 5 times on MacBook and didn't see test
> >> failure.
> >>
> >> Stack:
> >> Can you share the test output ?
> >>
> >> Thanks
> >>
> >>
> >> On Fri, Nov 25, 2011 at 5:04 PM, lars hofhansl <[email protected]
> >wrote:
> >>
> >>> I added testClosing as part of HBASE-4805, I'll have a look as soon as
> I
> >>> get a chance.
> >>>
> >>>
> >>>
> >>> ________________________________
> >>>  From: Stack <[email protected]>
> >>> To: HBase Dev List <[email protected]>
> >>> Sent: Friday, November 25, 2011 2:12 PM
> >>> Subject: Status of 0.92RC
> >>>
> >>> I'm having a little difficulty getting all tests to pass.  On
> >>> linux/ubuntu, TestHCM (testClosing strange issue) and TestReplication
> >>> are failing for me.  On mac osx, it'll build without fail about 50% of
> >>> the time.  I'd like to make it so tests pass all the time before
> >>> cutting the RC.  Thats what I'm at these times.
> >>>
> >>> Also, 0.92 build on jenkins has been turned off by Apache
> >>> Infrastructure.  It was hanging.  Its done this in the past too and
> >>> when it hangs it requires a jenkins reboot which doesn't make Apache
> >>> Infrastructure team too happy.  The hang looks to me like a Jenkins
> >>> bug because build hangs before we even checkout src.  Am trying to see
> >>> what can be done to get it going again but thats the story at the mo.
> >>>
> >>> St.Ack
> >>>
> >>
> >>
> >
>

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