maria-discuss team mailing list archive

[Brian Evans <grknight@xxxxxxxxxxxxxx>]

On 7/31/2017 9:15 AM, Reindl Harald wrote:
>
>
> Am 31.07.2017 um 15:01 schrieb Brian Evans:
>> On 7/31/2017 6:59 AM, Reindl Harald wrote:
>>> what the hell is this when the MYISAM database has a utf8 charset
>>> while this don't happen with latin1_german1_ci - this seems to be a
>>> regression in 10.2 and wasted an hour of time to realize what is going
>>> on just because anotehr guy did not take care of the database charset
>>>
>>> create table `cms1_formmailer_generic_cc` (`fg_key` mediumint(7)
>>> unsigned not null auto_increment, `fg_form` varchar(255) not null
>>> default '', `fg_email` varchar(255) not null default '', primary
>>> key(`fg_key`), key`fg_key` (`fg_form`, `fg_email`)) - Specified key
>>> was too long; max key length is 1000 bytes
>>
>> A UTF8 character takes 3 bytes (or 4 bytes with utf8mb4).  Your
>> secondary key is 255 * 3 * 2 or 1530 bytes
>
> but since when has MyISAM such key limits?
>
> i know from tests how the system behaves in InnoDB that there are
> horrible low limits for keys but not on MyISAM

Even back to 3.23, MyISAM, and by extension Aria, has a hard coded index
limit of 1000-bytes unless modified in the source code.
Source:
https://web.archive.org/web/20060110190745/http://dev.mysql.com:80/doc/refman/4.1/en/myisam-storage-engine.html

FWIW, the above statement works perfectly in 10.2.7 on InnoDB.

Brian