In addition to what Jon said please be aware that if compression is specified
in the table schema, it happens at the store file level -- compression happens
after write I/O, before read I/O, so if you transmit a 100MB object that
compresses to 30MB, the performance impact is that of 100MB, not 30MB.
I also try not to go above 50MB as largest cell size, for the same reason. I
have tried storing objects larger than 100MB but this can cause out of memory
issues on busy regionservers no matter the size of the heap. When/if HBase RPC
can send large objects in smaller chunks, this will be less of an issue.
Best regards,
- Andy
Why is this email five sentences or less?
http://five.sentenc.es/
--- On Mon, 9/6/10, Jonathan Gray <jg...@facebook.com> wrote:
> From: Jonathan Gray <jg...@facebook.com>
> Subject: RE: Limits on HBase
> To: "user@hbase.apache.org" <user@hbase.apache.org>
> Date: Monday, September 6, 2010, 4:10 PM
> I'm not sure what you mean by
> "optimized cell size" or whether you're just asking about
> practical limits?
>
> HBase is generally used with cells in the range of tens of
> bytes to hundreds of kilobytes. However, I have used
> it with cells that are several megabytes, up to about
> 50MB. Up at that level, I have seen some weird
> performance issues.
>
> The most important thing is to be sure to tweak all of your
> settings. If you have 20MB cells, you need to be sure
> to increase the flush size beyond 64MB and the split size
> beyond 256MB. You also need enough memory to support
> all this large object allocation.
>
> And of course, test test test. That's the easiest way
> to see if what you want to do will work :)
>
> When you run into problems, e-mail the list.
>
> As far as row size is concerned, the only issue is that a
> row can never span multiple regions so a given row can only
> be in one region and thus be hosted on one server at a
> time.
>
> JG
>
> > -----Original Message-----
> > From: William Kang [mailto:weliam.cl...@gmail.com]
> > Sent: Monday, September 06, 2010 1:57 PM
> > To: hbase-user
> > Subject: Limits on HBase
> >
> > Hi folks,
> > I know this question may have been asked many times,
> but I am wondering
> > if
> > there is any update on the optimized cell size (in
> megabytes) and row
> > size
> > (in megabytes)? Many thanks.
> >
> >
> > William
>
