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Re: threading with hive client
To add,

1. Being public doesn't necessarily guarantee thread-safety. Of course,
this is no excuse for not documenting thread-safety.
2. Sometimes a method is made public for testing, which is bad in my
opnion, but I saw many instances like this before.

--Xuefu

On Thu, Aug 15, 2013 at 1:11 PM, Brock Noland <[EMAIL PROTECTED]> wrote:

> Well you would have probably found the areas we need to fix! :) The hive
> source is is not strict about methods and member visibility. The good news
> is that we have been making significant improvements in this aspect.
>
> Brock
>
>
> On Thu, Aug 15, 2013 at 2:55 PM, Kristopher Glover <[EMAIL PROTECTED]
> >wrote:
>
> > Interesting, I didn't realize that. If that's the case then I suppose
> it'd
> > be really bad for me to circumvent the lock by reproducing the Driver#run
> > method by calling Driver#compile and Driver#execute directly from within
> > my app.
> >
> > If that is the case why make Driver#compile and Driver#execute public
> > methods? There doesn't seem to be any inheritance that requires them to
> be
> > public and the fact that they are public opens up a thread safety issue.
> >
> > Thanks,
> > Kris
> >
> > On 8/15/13 1:11 PM, "Brock Noland" <[EMAIL PROTECTED]> wrote:
> >
> > >The hive semantic analyzer is not fully thread safe.  We'd like to
> remove
> > >that lock but it will be a large project.
> > >
> > >Brock
> > >
> > >
> > >On Thu, Aug 15, 2013 at 11:12 AM, Kristopher Glover
> > ><[EMAIL PROTECTED]>wrote:
> > >
> > >> Hi Everyone,
> > >>
> > >> I'm experiencing a threading issue with the Hive client where I want
> to
> > >> run multiple queries on the same JVM.
> > >>
> > >>  The problem I'm having is that org.apache.hadoop.hive.ql.Driver#run
> > >>(line
> > >> 907)  has the following few lines of code :
> > >>
> > >>  synchronized (compileMonitor) {
> > >>
> > >>       ret = compile(command);
> > >>
> > >>     }
> > >>
> > >>
> > >> The compileMonitor is a static so it blocks all threads even though
> I'm
> > >> using different instances of the Driver class. I could explicitly call
> > >> Driver#compile then Driver#execute to avoid the synchronized block
> but I
> > >> don't know if it's serving a special purpose. Does anyone know why
> that
> > >> synchronized block is there and if its really necessary ?
> > >>
> > >>
> > >> Thanks,
> > >>
> > >> Kris
> > >>
> > >
> > >
> > >
> > >--
> > >Apache MRUnit - Unit testing MapReduce - http://mrunit.apache.org
> >
> >
>
>
> --
> Apache MRUnit - Unit testing MapReduce - http://mrunit.apache.org
>