Forget about this: it does not help
Le 20/11/12 19:54, Vincent Barat a ï¿½crit :
> It seems there is a potential contention in the HBase client code
> (a useless synchronized method)
> You may try to use this patch :
> I face similar issues on my production cluster since I upgraded to
> HBase 0.92. I will test this patch tomorrow...
> More info matter.
> Le 12/10/12 12:56, Ricardo Vilaï¿½a a ï¿½crit :
>> Em 11/10/12 04:24, Stack escreveu:
>>> On Wed, Oct 10, 2012 at 5:51 AM, Ricardo Vilaï¿½a
>>> <[EMAIL PROTECTED]> wrote:
>>>> However, when adding an additional client node, with also 400
>>>> the latency increases 3 times,
>>>> but the RegionServers remains idle more than 80%. I had tried
>>>> values for the hbase.regionserver.handler.count and also
>>>> for the hbase.client.ipc.pool size and type but without any
>>> I was going to suggest that it sounded like all handlers are
>>> occupied... but it sounds like you tried upping them.
>> Yes, had already tried to increase to 200 but without improvement
>> on the application latency. However, the output of the active IPC
>> handlers, using the Web interface,
>> is strange. For region servers I can see in a given instant at
>> most 4
>> IPC handler active but if I
>> see the state of all other IPC handlers they are waiting for 0
>> In the master the IPC handlers are also almost all in the waiting
>> but for a few seconds.
>>> Is this going from one client node (serving 400 clients) to two
>>> nodes (serving 800 clients)?
>> Yes, the huge increase in latency is when going for one client
>> node to
>> two client nodes. However, increasing the number of clients in a
>> node also adds to latency but a small increase.
>>> Where are you measuring from? Application side? Can you figure
>>> if we
>>> are binding up in HBase or in the client node?
>> This measures are from the application side. As the huge
>> increase in
>> is happening when increasing the number of clients I suspect that
>> binding up is in the
>> HBase maybe due to some incorrect configuration.
>>> What does a client node look like? It is something hosting an
>>> client? A webserver or something?
>> Yes, the client node is hosting an HBase client.
>>>> Is there any configuration parameter that can improve the
>>>> latency with
>>>> several concurrent threads and more than one HBase client node
>>>> and/or which JMX parameters should I monitor on RegionServers
>>>> to check
>>>> what may be causing this and how could I achieve better
>>>> utilization of CPU
>>>> at RegionServers?
>>> It sounds like all your data is memory resident given its size
>>> and the
>>> lack of iowait. Is that so? Studying the regionserver metrics,
>>> they fairly constant across the addition of the new client node?
>> Yes, all data is memory resident. As far as I can see, the
>> metrics are
>> fairly constant.