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From Li Pi ...@idle.li>
Subject Re: Status of 0.92RC
Date Sat, 26 Nov 2011 06:12:13 GMT
Very, very nice discovery!

Once I saw the move your mouse around part, I smiled.

Entropy can also be gathered from other system events, such as network
traffic, so on a production machine, you should always have enough
entropy. So it should be fine to change the test to use urandom.

On Fri, Nov 25, 2011 at 9:06 PM, lars hofhansl <lhofhansl@yahoo.com> 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 <stack@duboce.net>
> To: dev@hbase.apache.org
> Cc: lars hofhansl <lhofhansl@yahoo.com>
> 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 <yuzhihong@gmail.com> 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 <yuzhihong@gmail.com> 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 <lhofhansl@yahoo.com>wrote:
>>>
>>>> I added testClosing as part of HBASE-4805, I'll have a look as soon as I
>>>> get a chance.
>>>>
>>>>
>>>>
>>>> ________________________________
>>>>  From: Stack <stack@duboce.net>
>>>> To: HBase Dev List <dev@hbase.apache.org>
>>>> 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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