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From Nicolas Liochon <nkey...@gmail.com>
Subject Re: speed control on the server side
Date Wed, 18 Jun 2014 10:17:25 GMT
What do you mean by down? Does it crash?

The server does not block on 0.96, it immediately sends back an exception.
(See HBASE-9467)
The client is implicitly slowed down by the retries, w/o blocking on the
server. It's managed by the hbase client itself, and it's transparent for
the client application. You've got some logs (info level), to tell you that
something is happening, but that's it.

You can configure the client to be less more or less verbose
(hbase.client.start.log.errors.counter) or more or less pushy on the server
(for example hbase.client.max.perserver.tasks).



On Wed, Jun 18, 2014 at 11:59 AM, Li Li <fancyerii@gmail.com> wrote:

> hi all,
>     the hbase client send too much requests and the some region server
> down.
>     1. region server down because of gc pause
>         I can see it from log:
>        [JvmPauseMonitor] util.JvmPauseMonitor: Detected pause in JVM
> or host machine (eg GC): pause of approximately 3056ms
>          I can adjust zookeeper config
>     2. as a client, how can I know server is busy?
>          I am using hbase 0.96 with hadoop1. I can see log such as:
> org.apache.hadoop.hbase.client.AsyncProcess #178, table=vc2.url_db,
> attempt=13/35 SUCCEEDED on mphbase1,60020,1403084938641, tracking
> started Wed Jun 18 17:31:10 CST 2014
>          I googled and found
> http://apache-hbase.679495.n3.nabble.com/RegionTooBusyException-Above-memstore-limit-td4056339.html
>          it says in hbase 0.94, if the server is busy, it will block
> the client request. That's what I want, if the client send too much
> request than server can handle, it will be blocked. But in 0.96, it
> seems not.
>          I did not find any exception in client. So I can't slow the clien
> down.

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