drill-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Chris Westin <chriswesti...@gmail.com>
Subject Re: [DISCUSSION] should BufferAllocator.buffer() throw an OutOfMemoryException ?
Date Tue, 30 Jun 2015 20:31:50 GMT
I would resist using a checked exception. We would end up having to add it
to almost everything everywhere. Or constantly wrapping it with
RuntimeException to get around that; in which case why make it checked to
begin with?

On Tue, Jun 30, 2015 at 1:28 PM, Hanifi GUNES <hg@apache.org> wrote:

> I would propose throwing a checked exception encouraging explicit and
> consistent handling of this event. Each sub-system has liberty to decide if
> an OOM failure is fatal or non-fatal depending on its capabilities. Also if
> at some point a sub-system needs to communicate with its callers via a
> different mechanism such like using flags (boolean, enum etc) or raising an
> unchecked exception that's still fine, just handle the exception. If there
> is a need to suppress the checked exception that's fine too, just use a
> helper method.
>
> Either way, returning *null* sounds problematic in many ways i) it is
> implicit ii) unsafe iii) its handling logic is repetitive iv) it is
> semantically unclean to make null mean something - even worse something
> context specific.
>
>
> -Hanifi
>
> 2015-06-30 12:23 GMT-07:00 Abdel Hakim Deneche <adeneche@maprtech.com>:
>
> > I guess that would fix the issue too. But we may still run into
> situations
> > where the caller will pass a flag to "mute" the exception and not handle
> > the case anyway.
> >
> > If .buffer() unconditionally throws an exception, can't the caller, who
> > wants to, just catch that and handle it properly ?
> >
> > On Tue, Jun 30, 2015 at 12:13 PM, Chris Westin <chriswestin42@gmail.com>
> > wrote:
> >
> > > No, but we should do something close to that.
> > >
> > > There are cases where the caller can handle the inability to get more
> > > memory, and may be able to go to disk. However, you are correct that
> > there
> > > are many that can't handle an OOM, and that fail to check.
> > >
> > > Instead of unconditionally throwing OutOfMemoryRuntimeException, I
> would
> > > suggest that the buffer() call take a flag that indicates whether or
> not
> > it
> > > should throw if it is unable to fulfill the request. This way, the call
> > > sites that can handle an OOM can pass in the flag to return null, and
> the
> > > rest can pass in the flag value to throw, and not have to have any
> > checking
> > > code.
> > >
> > >
> > > On Tue, Jun 30, 2015 at 12:06 PM, Abdel Hakim Deneche <
> > > adeneche@maprtech.com
> > > > wrote:
> > >
> > > > our current implementations of BufferAllocator.buffer(int, int)
> returns
> > > > null when it cannot allocate the buffer.
> > > >
> > > > But looking through the code, there are many places that don't check
> if
> > > the
> > > > allocated buffer is null before trying to access it which will throw
> a
> > > > NullPointerException.
> > > >
> > > > ValueVectors' allocateNewSafe() seem to be the only place that handle
> > the
> > > > null in a specific manner.
> > > >
> > > > Should we update the allocators' implementation to throw an
> > > > OutOfMemoryRuntimeException instead of returning null ? this has the
> > > added
> > > > benefit of displaying a proper out of memory error message to the
> user.
> > > >
> > > > Thanks!
> > > >
> > > > --
> > > >
> > > > Abdelhakim Deneche
> > > >
> > > > Software Engineer
> > > >
> > > >   <http://www.mapr.com/>
> > > >
> > > >
> > > > Now Available - Free Hadoop On-Demand Training
> > > > <
> > > >
> > >
> >
> http://www.mapr.com/training?utm_source=Email&utm_medium=Signature&utm_campaign=Free%20available
> > > > >
> > > >
> > >
> >
> >
> >
> > --
> >
> > Abdelhakim Deneche
> >
> > Software Engineer
> >
> >   <http://www.mapr.com/>
> >
> >
> > Now Available - Free Hadoop On-Demand Training
> > <
> >
> http://www.mapr.com/training?utm_source=Email&utm_medium=Signature&utm_campaign=Free%20available
> > >
> >
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message