MediaWiki/Sql: Difference between revisions

==Debugging with the General Query Log==

In the mysql console, you can use a global variable to turn logging on

SET global general_log = 1;

And specify the log file (The MySQL user must have write permission to this file.)

SET global general_log_file = '/var/log/mariadb/mariadb.log';

Then you can do some action that you want to examine the queries for, and '''TURN OFF''' the general query log immediately.  A busy server will fill up all disk space with a huge log file if you don't turn it off.

SET global general_log = 0;

==Query Examples==

Some database queries that you might want to use and bookmark in your database administration tool such as [https://dev.mysql.com/downloads/workbench/ MySQL Workbench] or SQLyog http://www.webyog.com/en/index.php

-- what database schema do you want to use?

use wiki_demo;

FROM information_schema.columns AS cols  

WHERE table_schema = 'wiki_demo';

Here is a query that will show you the pages in your wiki that contain a particular string.  In this example, I wanted to find all pages that were using the 'Icon' extension parser extension magic word '#icon'.

SELECT DISTINCT  

   page_title

       old_text REGEXP('#icon') # regex is easier to deal with

     )

A more complex query that summarizes some information about an article

(You supply the article title)

SELECT  

   p.page_id 'id',  

WHERE  

   p.page_title = 'Main_Page'

==See Also==