I looked at the code (for better understanding of problem), and now I have some questions:
Do I understand correctly, that now it is stored as an int64 value with a scale and we want to extend it, and store maximum 65 digits as in documentation?
https://github.com/mariadb-corporation/mariadb-columnstore-engine/blob/master/dbcon/execplan/treenode.h#L62

We will use fixed size type or extandable?

I think that I will find all answers of my questions in specification, and there is no point in asking more questions.

Regards,
Daniil Medvedev

2017-03-20 21:51 GMT+03:00 Andrew Hutchings <andrew@linuxjedi.co.uk>:
Hi Daniil,

Many thanks for your interest. We haven't fully specified it yet (I'll
build a full specification later this week). But I suspect the following
would be involved:

* Implementation of methods to handle MariaDB's DECIMAL format
* Support for a longer than 8-byte numeric column type (there is an
InfiniDB tree with work for this already)
* Modification of the primitives processor for the math
* Modification of the function expression processor to handle the new type
* Version upgrade support for DECIMAL from the current form to the new form

In the mean time please let me know if you have any questions.

Kind Regards
Andrew
(Senior Software Engineer, MariaDB ColumnStore)

On 19/03/17 23:09, Даниил Медведев wrote:
> Hello,
>
> I took part in GSoC last year, and closed one of MariaDB tasks. Now I
> want to continue programming with MariaDB developers and solve a new task.
> I considered some of proposed tasks, and was interested in "ColumnStore:
> Add full support for DECIMAL".
> I think this task is doable in the given time and I might solve it.
>
> P.S. My github link: https://github.com/medvdanil
>
> Regards,
> Daniil Medvedev
>
>
>
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--
Andrew Hutchings - LinuxJedi - http://www.linuxjedi.co.uk/