maria-discuss team mailing list archive

[Roberto Spadim <roberto@xxxxxxxxxxxxx>]

yeah, no materialized yet, but this have a limit? maybe max sql query size?

about spider any idea about limits?

2014-01-30 Reindl Harald <h.reindl@xxxxxxxxxxxxx>:
>
>
> Am 30.01.2014 19:36, schrieb Roberto Spadim:
>> nice, now one question...
>> what about views? how many columns?
>> what about spider engine with vertical partition? how many columns?
>
> views - caution - no materialized views in MySQL
>
> means implicit querys in the background while you tink
> your select statement is tiny and fast :-)
>
> http://en.wikipedia.org/wiki/Materialized_view
>
> in general i would say avoid too many columns and consider
> what is really accessed always at the same time and what
> can be in a different table with a foreign key / reference
>
>> 2014-01-30 Reindl Harald <h.reindl@xxxxxxxxxxxxx>:
>>> http://dev.mysql.com/doc/refman/5.5/en/column-count-limit.html
>>>
>>> normally you have a serious problem if you reach that limits
>>> because it won't scale well and the scheme is at least
>>> questionable
>>>
>>> select(*) even with most empty will create large results
>>> inserts/updates are much slower
>>>
>>> Am 30.01.2014 18:50, schrieb Roberto Spadim:
>>>> hum, unireg is the "global" limit, there's some ideas to change the .frm file and create a better one with less
>>>> limits (drizzle database have it done), but you have limits in each engine too, index size have limits, many limits
>>>> per engine exists, i think a max columns is just more one
>>>>
>>>> how many columns you need? i think it's the best question, after that select a engine, if it's not a good engine,
>>>> create many tables and use spider engine to group all tables (vertical partition) ?
>>>>
>>>>
>>>> 2014-01-30 Adam Scott <adam.c.scott@xxxxxxxxx <mailto:adam.c.scott@xxxxxxxxx>>:
>>>>
>>>>     I believe it's the same as in MySQL.  It does depend on the engine your table is using.  By default it is
>>>>     probably InnoDB.
>>>>
>>>>     For the full details about the limits:
>>>>     http://www.mysqlperformanceblog.com/2013/04/08/understanding-the-maximum-number-of-columns-in-a-mysql-table/
>>>>
>>>>
>>>>
>>>>
>>>>     On Thu, Jan 30, 2014 at 9:45 AM, AskMonty KB <noreply@xxxxxxxxxxxx <mailto:noreply@xxxxxxxxxxxx>> wrote:
>>>>
>>>>         Hello,
>>>>
>>>>         A new question has been asked in "MariaDB FAQ" by robpaton:
>>>>         --------------------------------
>>>>         Hi there,
>>>>
>>>>         What is the maximum number of columns a row can have in MariaDB? I can't find this info anywhere on the web.
>>>>
>>>>         Best regards,
>>>>         Rob
>>>>         --------------------------------
>
>
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-- 
Roberto Spadim
SPAEmpresarial
Eng. Automação e Controle