[Phpmyadmin-devel] Minimum MySQL version

Marc Delisle marc at infomarc.info
Fri Oct 25 21:50:03 CEST 2013

Marc Delisle a écrit :
> Le 2013-10-24 15:59, Rouslan Placella a écrit :
>> On 10/24/2013 08:28 PM, Marc Delisle wrote:
>>> Marc Delisle a écrit :
>>>> 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.
>>> I have a test server on Linux, with MySQL 5.1.71, 1000 databases with 
>>> 100 tables in each db (all InnoDB). PHP 5.5.3 + mysqli + mysqlnd.
>> How many records per table have you got? I guess that the amount of data
>> may have an influence here.
> These tables are empty but tomorrow I'll write sample data into them.
> Also, I should add more columns into them.

In the first 100 databases, for each of their 100 tables, I have written 
100 rows.

The navi panel still answers quickly.

>>> With phpMyAdmin 4.0.8, I don't have a performance problem. Both my root 
>>> user, which happily paginates between all the dbs, and a normal user 
>>> with access to only one db, work well.
>>> I'm using the default DisableIS setting of true. I also tried 
>>> ShowDatabasesCommand set to false + some names in only_db, and all was fine.
>>> I have asked in the bug tickets for more details, to be able to 
>>> reproduce the performance problems.
>>> I am not testing with MySQL 5.0.x, because for phpMyAdmin 4.1 we should 
>>> mention that the minimum version is (at least) MySQL 5.1.

Marc Delisle

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