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HBase >> mail # dev >> HBase read perfomnance and HBase client


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Re: HBase read perfomnance and HBase client
Exactly, but this thread dump is from RS under load nevertheless (you can
see that one thread is in JAVA and reading data from socket)
On Tue, Jul 30, 2013 at 1:35 PM, Jean-Daniel Cryans <[EMAIL PROTECTED]>wrote:

> FWIW nothing is happening in that thread dump.
>
> J-D
>
> On Tue, Jul 30, 2013 at 1:15 PM, Vladimir Rodionov
> <[EMAIL PROTECTED]> wrote:
> > Sure, here it is:
> >
> > http://pastebin.com/8TjyrKRT
> >
> > epoll is not only to read/write HDFS but to connect/listen to clients as
> > well?
> >
> >
> > On Tue, Jul 30, 2013 at 12:31 PM, Jean-Daniel Cryans <
> [EMAIL PROTECTED]>wrote:
> >
> >> Can you show us what the thread dump looks like when the threads are
> >> BLOCKED? There aren't that many locks on the read path when reading
> >> out of the block cache, and epoll would only happen if you need to hit
> >> HDFS, which you're saying is not happening.
> >>
> >> J-D
> >>
> >> On Tue, Jul 30, 2013 at 12:16 PM, Vladimir Rodionov
> >> <[EMAIL PROTECTED]> wrote:
> >> > I am hitting data in a block cache, of course. The data set is very
> small
> >> > to fit comfortably into block cache and all request are directed to
> the
> >> > same Region to guarantee single RS testing.
> >> >
> >> > To Ted:
> >> >
> >> > Yes, its CDH 4.3 . What the difference between 94.10 and 94.6 with
> >> respect
> >> > to read performance?
> >> >
> >> >
> >> > On Tue, Jul 30, 2013 at 12:06 PM, Jean-Daniel Cryans <
> >> [EMAIL PROTECTED]>wrote:
> >> >
> >> >> That's a tough one.
> >> >>
> >> >> One thing that comes to mind is socket reuse. It used to come up more
> >> >> more often but this is an issue that people hit when doing loads of
> >> >> random reads. Try enabling tcp_tw_recycle but I'm not guaranteeing
> >> >> anything :)
> >> >>
> >> >> Also if you _just_ want to saturate something, be it CPU or network,
> >> >> wouldn't it be better to hit data only in the block cache? This way
> it
> >> >> has the lowest overhead?
> >> >>
> >> >> Last thing I wanted to mention is that yes, the client doesn't scale
> >> >> very well. I would suggest you give the asynchbase client a run.
> >> >>
> >> >> J-D
> >> >>
> >> >> On Tue, Jul 30, 2013 at 11:23 AM, Vladimir Rodionov
> >> >> <[EMAIL PROTECTED]> wrote:
> >> >> > I have been doing quite extensive testing of different read
> scenarios:
> >> >> >
> >> >> > 1. blockcache disabled/enabled
> >> >> > 2. data is local/remote (no good hdfs locality)
> >> >> >
> >> >> > and it turned out that that I can not saturate 1 RS using one
> >> >> (comparable in CPU power and RAM) client host:
> >> >> >
> >> >> >  I am running client app with 60 read threads active (with
> multi-get)
> >> >> that is going to one particular RS and
> >> >> > this RS's load is 100 -150% (out of 3200% available) - it means
> that
> >> >> load is ~5%
> >> >> >
> >> >> > All threads in RS are either in BLOCKED (wait) or in IN_NATIVE
> states
> >> >> (epoll)
> >> >> >
> >> >> > I attribute this  to the HBase client implementation which seems
> to be
> >> >> not scalable (I am going dig into client later on today).
> >> >> >
> >> >> > Some numbers: The maximum what I could get from Single get (60
> >> threads):
> >> >> 30K per sec. Multiget gives ~ 75K (60 threads)
> >> >> >
> >> >> > What are my options? I want to measure the limits and I do not
> want to
> >> >> run Cluster of clients against just ONE Region Server?
> >> >> >
> >> >> > RS config: 96GB RAM, 16(32) CPU
> >> >> > Client     : 48GB RAM   8 (16) CPU
> >> >> >
> >> >> > Best regards,
> >> >> > Vladimir Rodionov
> >> >> > Principal Platform Engineer
> >> >> > Carrier IQ, www.carrieriq.com
> >> >> > e-mail: [EMAIL PROTECTED]
> >> >> >
> >> >> >
> >> >> > Confidentiality Notice:  The information contained in this message,
> >> >> including any attachments hereto, may be confidential and is intended
> >> to be
> >> >> read only by the individual or entity to whom this message is
> >> addressed. If
> >> >> the reader of this message is not the intended recipient or an agent