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HBase, mail # user - CheckAndAppend Feature


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Jerry Lam 2012-08-07, 15:22
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syed kather 2012-08-07, 16:09
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syed kather 2012-08-07, 16:12
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lars hofhansl 2012-08-07, 15:55
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Alex Baranau 2012-08-07, 16:00
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lars hofhansl 2012-08-08, 00:30
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Re: CheckAndAppend Feature
Michael Segel 2012-08-08, 00:54
While this may be a trivial fix, have you considered possible down sides to the implementation?

I'm not sure its a bad idea, but one that could have some potential issues when put into practice.

-Mike

On Aug 7, 2012, at 7:30 PM, lars hofhansl <[EMAIL PROTECTED]> wrote:

> I filed HBASE-6522. It is a trivial change to make locks and leases available to coprocessors.
> So checkAndSet type operations can then be implemented via coprocessor endpoints: lock row, check, fail or update, unlock row.
>
> Since the patch is so simple I'll commit that soon (to 0.94.2 and 0.96)
>
>
> -- Lars
>
> ________________________________
> From: lars hofhansl <[EMAIL PROTECTED]>
> To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> Sent: Tuesday, August 7, 2012 8:55 AM
> Subject: Re: CheckAndAppend Feature
>
> There is no such functionality currently, and there is no good way to simulate that.
>
> Currently that cannot even be done with a coprocessor endpoint, because region coprocessors have no way to create a region lock (just checked the code).
> (That is something we have to change I think - I will create an issue once the Jira system is back from the walk in the park).
>
> -- Lars
>
>
> ----- Original Message -----
> From: Jerry Lam <[EMAIL PROTECTED]>
> To: user <[EMAIL PROTECTED]>
> Cc:
> Sent: Tuesday, August 7, 2012 8:22 AM
> Subject: CheckAndAppend Feature
>
> Hi HBase community:
>
> I checked the HTable API, it has checkAndPut and checkAndDelete but I'm
> looking for checkAndAppend. Is there a way to simulate similarly?
> For instance, I want to check the last 32 bytes of a value (let assume that
> it has 128 bytes in total) in a column before appending atomically some
> values into it.
>
> Thanks!
>
> Jerry
>
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lars hofhansl 2012-08-08, 01:05
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Michael Segel 2012-08-08, 01:25
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lars hofhansl 2012-08-08, 02:04
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Jerry Lam 2012-08-08, 00:50