Mailing-List: contact dev-help@hbase.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@hbase.apache.org
Received-SPF: pass (nike.apache.org: domain of vladrodionov@gmail.com
 designates 74.125.82.43 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <1384050881.13692359@apps.rackspace.com>
References: <1384043054.338531290@apps.rackspace.com>
	<CALte62z49uOLPREftuuObgkHO3tTNuTbCPKqF8F1e6KvVxzh6Q@mail.gmail.com>
	<1384050881.13692359@apps.rackspace.com>
Date: Sat, 9 Nov 2013 21:44:06 -0800
Message-ID: 
 <CAAg3a2oMwN45h=wsUN5nCmnQrKetj3Ot9qksgWA9ye5ujJaObg@mail.gmail.com>
Subject: Re: problems with theUnsafe
From: Vladimir Rodionov <vladrodionov@gmail.com>
To: "dev@hbase.apache.org" <dev@hbase.apache.org>
Content-Type: multipart/alternative; boundary=f46d043c7f2692a1c304eacc1ac0

--f46d043c7f2692a1c304eacc1ac0
Content-Type: text/plain; charset=ISO-8859-1

Interesting, it seems that you are the first user who is trying HBase
(0.94.7) on IBM JRE. Which version of IBM JRE are you using? Unsafe MUST be
supported by IBM JRE in Java 6.


On Sat, Nov 9, 2013 at 6:34 PM, <youknowwho@heroicefforts.net> wrote:

>
> I don't have access to the system at the moment (SE 6 RHEL 64-bit).
>  Basically, invoking a client Get operation causes the app server / JRE to
> core dump. I wasn't able to find any specific IBM bug associated with this
> behavior, but their issue tracking is not exactly transparent.  I don't
> think that this will work:
>
> try { } catch(CoreDump) {  :D  }
>
> Avro and others allow explicit avoidance:
>
> if("false".equals(System.getProperty("hbase.disable.unsafe", "false"))
> //attempt unsafe impl
> else
> //use pure impl
>
> An alternative might be to whitelist java.vendor.
>
> However, I think the explicit solution is better than trying to be too
> clever.
>
> -----Original Message-----
> From: "Ted Yu" <yuzhihong@gmail.com>
> Sent: Saturday, November 9, 2013 8:28pm
> To: "dev@hbase.apache.org" <dev@hbase.apache.org>
> Subject: Re: problems with theUnsafe
>
>
>
> bq. The IBM JRE supplies Unsafe, but apparently it doesn't work
>
> Can you give us a bit more detail (in this case, UnsafeComparer) ? Is there
> a BUG associated with it ?
>
> If there is a known procedure / test by which we can tell whether
> UnsafeComparer
> works or not, that would help make the decision of switching to pure Java
> comparer.
>
> Cheers
>
>
> On Sat, Nov 9, 2013 at 4:24 PM, <youknowwho@heroicefforts.net> wrote:
>
> >
> > Our WebSphere Application Server started core dumping immediately after
> we
> > merged our hbase feature branch to our mainline.  I've tracked this down
> to
> > Bytes use of theUnsafe.  The IBM JRE supplies Unsafe, but apparently it
> > doesn't work worth a damn.  I managed to temporarily work "around" the
> > issue using some AOP wizardry.  Would it be possible to add some property
> > check to the static initializer to allow one to explicitly opt for the
> pure
> > Java comparer?
> >
> >
> >
> http://grepcode.com/file/repo1.maven.org/maven2/org.apache.hbase/hbase/0.94.7/org/apache/hadoop/hbase/util/Bytes.java#Bytes.LexicographicalComparerHolder.getBestComparer%28%29
> >
> > thanks,
> >
> > -Jess
>

--f46d043c7f2692a1c304eacc1ac0--