[Phpmyadmin-devel] Minimum MySQL version

Marc Delisle marc at infomarc.info
Thu Oct 24 15:56:51 CEST 2013

Michal Čihař a écrit :
> Hi
> Dne Thu, 24 Oct 2013 08:15:48 -0400
> Marc Delisle <marc at infomarc.info> napsal(a):
>> For the upcoming phpMyAdmin 4.1, we currently advertise the minimum 
>> MySQL version to 5 (meaning 5.0). However, MySQL 5.0 has reached "End of 
>> Product Lifecycle".
>> Moreover, we have a performance problem in phpMyAdmin 4.0 and 4.1, due 
>> to the navi panel mostly using INFORMATION_SCHEMA, which is poorly 
>> implemented in older MySQL versions. This performance problem is seen on 
>> servers with many (thousands?) of databases, which is not uncommon for 
>> host providers. We have bug tickets about this.
>> By the way, using INFORMATION_SCHEMA helps us for some features like the 
>> db filter (now with REGEX). I'm not sure how we could implement this 
>> efficiently with SHOW DATABASES.
>> I would like to increase the minimum MySQL version for phpMyAdmin 4.1. I 
>> got feedback from someone I trust, who is running MySQL 5.6 with 
>> thousands of real-world databases and did some tests; on this version, 
>> INFORMATION_SCHEMA performs ok.
> When trying to google this, I've found following hint on improving IS
> performance, have we tried to use that?
> http://www.mysqlperformanceblog.com/2011/12/23/solving-information_schema-slowness/

I was not aware of that setting; but from the comments on this page:

"the innodb_stats_on_metadata variable is available since MySQL 5.1.17, 
and it’s a dynamic variable only since InnoDB Plugin 1.0.2."

>> If the team agrees, I would do some testing to find out at which point 
>> INFORMATION_SCHEMA's fetch problems were fixed. Then we would advertise 
>> this MySQL version as the minimum, and use only INFORMATION_SCHEMA in it 
>> (no more SHOW DATABASES).
> Makes sense (and we could then also drop DisableIS configuration...).

This, and ShowDatabasesCommand.

Marc Delisle

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