query hang after previous cancellation in SQLLine - throttling?

[Daniel Barclay <db...@maprtech.com>]

In investigating the problem where sometimes canceling a query that
returns a lot of data causes all subsequent queries to hang in SQLLine,
I notice (from tailing logs) that there is RPC activity every 5 seconds
or so (while the subsequent query is hung in SQLLine inside the JDBC
client-side code waiting for query-results messages).

It's not clear yet whether the server is slowly sending data to the client
because things are throttled, or I'm seeing some other communication.
(Some code mention fragment statuses, so maybe I'm seeing internal
communication.)

Does throttling have a minimum speed?  Does it send a message every
5 seconds when fully throttled?


Does the 5-second interval ring any other bells (re which
communication it is)?


Thanks,
Daniel
-- 
Daniel Barclay
MapR Technologies

Re: query hang after previous cancellation in SQLLine - throttling?

[Abdel Hakim Deneche <ad...@maprtech.com>]

I know there is a StatusThread in WorkManager that sends statistics for all
running queries every 5 seconds

On Sat, May 9, 2015 at 11:36 AM, Daniel Barclay <db...@maprtech.com>
wrote:

> In investigating the problem where sometimes canceling a query that
> returns a lot of data causes all subsequent queries to hang in SQLLine,
> I notice (from tailing logs) that there is RPC activity every 5 seconds
> or so (while the subsequent query is hung in SQLLine inside the JDBC
> client-side code waiting for query-results messages).
>
> It's not clear yet whether the server is slowly sending data to the client
> because things are throttled, or I'm seeing some other communication.
> (Some code mention fragment statuses, so maybe I'm seeing internal
> communication.)
>
> Does throttling have a minimum speed?  Does it send a message every
> 5 seconds when fully throttled?
>
>
> Does the 5-second interval ring any other bells (re which
> communication it is)?
>
>
> Thanks,
> Daniel
> --
> Daniel Barclay
> MapR Technologies
>



-- 

Abdelhakim Deneche

Software Engineer

  <http://www.mapr.com/>


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