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Date: Tue, 17 Sep 2013 11:48:31 -0600
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Subject: Re: How to manage retry failures in the HBase client
From: Tom Brown <tombrown52@gmail.com>
To: "user@hbase.apache.org" <user@hbase.apache.org>
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I had read that section for those values, but it was unclear (the
hbase.client.retries.number description subtly switches to describe
hbase.client.pause, and I missed that context switch).

If I could make a recommendation as to changing those items descriptions, I
would rearrange it like so:

hbase.client.pause
General client pause value. Used mostly as value to wait before running a
retry of a failed get, region lookup, etc. The actual retry interval is a
rough function based on this setting. At first we retry at this interval
but then with backoff, we pretty quickly reach retrying every ten seconds.
See HConstants#RETRY_BACKOFF for how the backup ramps up.

Default: 100

hbase.client.retries.number
Maximum retries. Used as maximum for all retryable operations such as the
getting of a cell's value, starting a row update, etc. Change this setting
and hbase.client.pause to suit your workload.

Default: 35


What is the formal way to request a specific documentation change? Do I
need to sign a contributor agreement?

--Tom


On Tue, Sep 17, 2013 at 11:40 AM, Ted Yu <yuzhihong@gmail.com> wrote:

> Have you looked at
> http://hbase.apache.org/book.html#hbase_default_configurations where
> hbase.client.retries.number
> and hbase.client.pause are explained ?
>
> Cheers
>
>
> On Tue, Sep 17, 2013 at 10:34 AM, Tom Brown <tombrown52@gmail.com> wrote:
>
> > I have a region-server coprocessor that scans it's portion of a table
> based
> > on a request and summarizes the results (designed this way to reduce
> > network data transfer).
> >
> > In certain circumstances, the HBase cluster gets a bit overloaded, and a
> > query will take too long. In that instance, the HBase client will retry
> the
> > query (up to N times). When this happens, any other running queries will
> > often timeout and generate retries as well. This results in the cluster
> > becoming unresponsive, until I'm able to kill the clients that are
> retrying
> > their requests.
> >
> > I have found the "hbase.client.retries.number" property, but that doesn't
> > claim to set the number of retries, rather the amount of time between
> > retries. Is there a different property I can use to set the maximum
> number
> > of retries? Or is this property mis-documented?
> >
> > Thanks in advance!
> >
> > --Tom
> >
>

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