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HBase, mail # user - HBase read latency


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Re: HBase read latency
Amandeep Khurana 2011-03-26, 19:03
What is your typical row size? How many column families? How many columns in each family?

On Mar 26, 2011, at 10:01 AM, Hari Sreekumar wrote:

> Hi guys,
>
> On what factors does HBase read latency primarily depend? What would be the
> approx theoretical limit for read latency in v0.90.1 on a cluster of 7 nodes
> (16 core/16 GB RAM on 5 machines and 36 GB on the other two)? I have an
> application where I generate around 1000 rows/s to be input into HBase.

> Then
> I have to read this data and process it at regular intervals. Write speed is
> not a problem as the cluster seems to be able to write at the reqd. rate.
> But while processing this data also, I would need a read speed of at least
> 1000 rows/s since I need to keep the processing speed at least equal to the
> data generation speed. So far, I am getting around 200-300 rows/s only it
> seems. I have LZO compression on the tables and I haven't tried in-memory
> yet as my RAM usage is too high already while running jobs. Is it possible
> to achieve this read speed, and what can I do to improve it? How far can
> adding more nodes/more RAM help? Please let me know if the scope is too huge
> to answer this question and if you need more details.
>
> Thanks,
> Hari