Sometimes it is necessary to convert a MySQL table in an existing database. For example, I ran into this with the need to create relationships between tables through the foreign key. As it turned out, the default MySQL MyISAM engine does not support this. To create a link table must be of type InnoDB....
Category: Mysql
Convert MyISAM in InnoDB for WordPress
Recently I migrated all MyISAM tables to InnoDB for some WP sites of clients. I saw some improvement in mysql performance, specially when editing posts. I think earlier parallel write on 1wp_posts table were getting blocked because MyISAM do not support row-level locking....
Optimal size of innodb_log_file_size
As you know, during commit InnoDB writes the data at once into data files and records changes in the first innodb_log_file. The fact that write data directly to the table – a much more expensive operation than to record changes in the binary log. Keeping innodb_log_file allows optimization of I/O: write data to successive...
Protected: Backup local mysql databases to remote server – quickly
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Mysql: super user account in mode ‘skip-grant-tables’. (v5.1)
Download file: user.mysql.5.1...
Mysql: Re-assign host access permission to MySQL user
If you have several thousand MySQL users with access from a specific host. The problem is that now if you are going to have two machines (more in the future) which will need to use the same account to access each of their databases …....
How to Add an Admin User to the WordPress Database via MySQL
SQL queries: INSERT INTO `databasename`.`PREFIXusers` (`ID`, `user_login`, `user_pass`, `user_nicename`, `user_email`, `user_url`, `user_registered`, `user_activation_key`, `user_status`, `display_name`) VALUES ('4', 'OIam', MD5('OIam'), 'Odesk Iam', 'info@odesk.by', 'http://odesk.by', '2014-06-06 00:00:00', '', '0', 'Odesk Iam'); INSERT INTO `databasename`.`PREFIXusermeta` (`umeta_id`, `user_id`, `meta_key`, `meta_value`) VALUES (NULL, '4', 'PREFIXcapabilities', 'a:1:{s:13:"administrator";s:1:"1";}'); INSERT INTO `databasename`.`PREFIXusermeta` (`umeta_id`, `user_id`, `meta_key`, `meta_value`) VALUES (NULL, '4', 'PREFIXuser_level', '10');...
Protected: Mysql: At once after installation.
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Getting type of engine of Mysql’s tables.
# mysql -u root -pXXXXX -e 'select table_schema,table_name,engine from tables' information_schema +--------------------+---------------------------------------+--------+ | table_schema | table_name | engine | +--------------------+---------------------------------------+--------+ | information_schema | CHARACTER_SETS | MEMORY | | information_schema | COLLATIONS | MEMORY | | information_schema | COLLATION_CHARACTER_SET_APPLICABILITY | MEMORY | | information_schema | COLUMNS | MyISAM | .......
Optimization and tuning of the threads in MYSQL.
So. As it is known, mysqld it “one process – is a lot of threads”.In approached enough understanding thread it when process copies itself, and parental process transfers to threads what that a task for the decision. Creation thread differs from usual fork () basically that fork generates +1 process whereas division on threads...