Hello, Ok, i'll write a proposal according to this description at the end of the week and will send the link to it.
Regards 2017-03-27 17:07 GMT+03:00 Andrew Hutchings <[email protected]>: > Hi Daniil, > > Just to keep you updated I have created a ticket with some basic > information in it (which we have already gone though) and updated the > MariaDB KB 2017 page accordingly. > > The ticket can be found here: https://jira.mariadb.org/browse/MCOL-641 > > Kind Regards > Andrew > > On 20/03/17 22:52, Andrew Hutchings wrote: > > Hi Daniil, > > > > Yes, it is currently stored as an int64. We want to extend it but also > > some of the internal functionality converts it to a double (see > > utils/funcexp/func_math.cpp for example). Every function would need to > > be fully tested to make sure that it uses DECIMAL end-to-end and handles > > overflow scenarios correctly. > > > > At the moment ColumnStore's integer storage can only handle fixed 1, 2, > > 4 and 8 byte columns. 2, 4 and 8 are used for DECIMAL. It should be > > somewhat easily extendible to 16 byte columns. I believe this will give > > us the capability to store the same amount of digits as MariaDB. If at > > CREATE TABLE it is determined that a DECIMAL will only require 8 bytes > > it should only use an 8 byte column, if it needs bigger it should use a > > 16 byte column. > > > > In addition the DDL code in ColumnStore will need modifying to handle > > the range. > > > > The ability to have 16 byte columns will also help us at a later date > > with other potential data types in the future too. > > > > Here is the first attempt at implementing 16byte columns in InfiniDB. > > This work has not made its way into ColumnStore yet and there are likely > > quite a few things this doesn't touch: > > > > https://github.com/infinidb/infinidb/commit/ > eb1e2df76bda95a43cd2948890bff98f8785a805 > > > > Kind Regards > > Andrew > > > > On 20/03/17 21:57, Даниил Медведев wrote: > >> 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 <[email protected] > >> <mailto:[email protected]>>: > >> > >> 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 > >> > > >> > > >> > > >> > _______________________________________________ > >> > Mailing list: https://launchpad.net/~maria-developers > >> <https://launchpad.net/~maria-developers> > >> > Post to : [email protected] > >> <mailto:[email protected]> > >> > Unsubscribe : https://launchpad.net/~maria-developers > >> <https://launchpad.net/~maria-developers> > >> > More help : https://help.launchpad.net/ListHelp > >> <https://help.launchpad.net/ListHelp> > >> > > >> > >> -- > >> Andrew Hutchings - LinuxJedi - http://www.linuxjedi.co.uk/ > >> > >> > > > > -- > Andrew Hutchings - LinuxJedi - http://www.linuxjedi.co.uk/ >
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