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From Vladimir Rodionov <vladrodio...@gmail.com>
Subject Re: Question about reading data very recently written to hbase
Date Mon, 05 Oct 2015 20:48:07 GMT
HBase writes are consistent.  Writes are available immediately only after
table's flush on a client side.
 (HTable.flushCommits())

-Vlad



On Mon, Oct 5, 2015 at 1:30 PM, Mike Thomsen <mikerthomsen@gmail.com> wrote:

> My team has a set of web services that read data from HBase and prepare it
> to be exported as a report. The first call is an AJAX call that reads all
> of the requested rows, generates the report pieces and returns a JSON map
> to the calling web app saying what level of success it had in building up
> the data for the report. If the data can be exported, it then display a
> link to another web service that builds the report and sends it as a file
> download to the user.
>
> In the first call, it's pretty quick between reading the data and
> immediately writing a copy of the report data to a table in HBase. So the
> turn around time between the two web service calls is usually about five
> seconds or less.
>
> We sometimes get errors back from HBase on the first attempt because it
> appears to have not committed the data from the Java client API to the
> server. Something like that. It can't immediately find the data we just
> generated. If we wait a few more seconds and try it again, everything works
> just right. It just appears to be the case that the data isn't flushed into
> a state where it's accessible yet.
>
> To be frank, we're HBase novices and we're probably missing something
> pretty simple and obvious. Is this to be expected? If so, does anyone have
> a recommendation for how we can mitigate this I/O behavior?
>
> Thanks,
>
> Mike
>

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