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From Richard Shaw <rs...@maprtech.com>
Subject Re: exec.queue.enable
Date Wed, 13 May 2015 21:51:38 GMT
Thank you Kristine

Please can you confirm the following would have the desired effect of
completely serialising all incoming queries?

    ALTER SYSTEM SET `exec.queue.enable`=true;
    ALTER SYSTEM SET `exec.queue.small`=1;
    ALTER SYSTEM SET `exec.queue.large`=1;


Kind Regards,
Richard


On 30 April 2015 at 14:46, Kristine Hahn <khahn@maprtech.com> wrote:

> Set options in sys.options to enable and manage query queuing, which is
> turned off by default. There are two types of queues: large and small. You
> configure a maximum number of queries that each queue allows by configuring
> the following options in the sys.options table:
>
>    - exec.queue.large
>    - exec.queue.small
>
> Example Configuration
>
> For example, you configure the queue reserved for large queries to hold a
> 5-query maximum. You configure the queue reserved for small queue to hold
> 20 queries. Users start to run queries, and Drill receives the following
> query requests in this order:
>
>    - Query A (blue): 1 billion records, Drill estimates 10 million rows
>    will be processed
>    - Query B (red): 2 billion records, Drill estimates 20 million rows
>    will be processed
>    - Query C: 1 billion records
>    - Query D: 100 records
>
> The exec.queue.threshold default is 30 million, which is the estimated
> rows to be processed by the query. Queries A and B are queued in the large
> queue. The estimated rows to be processed reaches the 30 million threshold,
> filling the queue to capacity. The query C request arrives and goes on the
> wait list, and then query D arrives. Query D is queued immediately in the
> small queue because of its small size, as shown in the following diagram:
>
> [image: Inline image 1]
>
> The Drill queuing configuration in this example tends to give many users
> running small queries a rapid response. Users running a large query might
> experience some delay until an earlier-received large query returns and the
> large queue is available to continue processing large queries.
>
> Kristine Hahn
> Sr. Technical Writer
> 415-497-8107 @krishahn
>
>
> On Thu, Apr 30, 2015 at 12:04 AM, Richard Shaw <rshaw@maprtech.com> wrote:
>
>> I'd like to better understand queuing, if it's in fact possible to
>> serialise incoming queries, especially where I have a very small Drill
>> installation with limited resources.
>>
>> Thank you
>>
>> Kind Regards,
>> Richard
>>
>
>

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