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From yanqing weng <wengyanq...@gmail.com>
Subject Re: elastic execution engine question
Date Fri, 01 Jul 2016 01:40:05 GMT
Thanks Hubert.

Can it be set only use one virtual segment for the query ? Because this can
debug query more easily.


On Fri, Jul 1, 2016 at 9:35 AM, Hubert Zhang <hzhang@pivotal.io> wrote:

> For hash tables, The number of virtual segments is equal to the bucket
> number of the table. Bucket number can be specified when creating the table.
>
> On Fri, Jul 1, 2016 at 9:31 AM, Ivan Weng <iweng@pivotal.io> wrote:
>
>> How about hash table?
>>
>> On Fri, Jul 1, 2016 at 9:30 AM, Hubert Zhang <hzhang@pivotal.io> wrote:
>>
>> > For random table, the virtual segment number is related to the data
>> size of
>> > the table. For large tables, we prefer use more virtual segments to
>> achieve
>> > better performance. While for small tables, less virtual segments are
>> > needed, which could save resources and enable more concurrent queries.
>>
>> >
>> > On Fri, Jul 1, 2016 at 9:22 AM, yanqing weng <wengyanqing@gmail.com>
>> > wrote:
>> >
>> > > Hi HAWQ developer,
>> > >
>> > > Elastic execution engine is the important feature in HAWQ 2.0.
>> > >
>> > > I have a question for this feature in the HAWQ debugging. Is there
>> > possible
>> > > to control the virtual segment number when run query ? If so, which
>> GUC
>> > or
>> > > parameter I should set ? Thanks.
>> > >
>> >
>> >
>> >
>> > --
>> > Thanks
>> >
>> > Hubert Zhang
>> >
>>
>
>
>
> --
> Thanks
>
> Hubert Zhang
>

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