Mysql notes

From Simson Garfinkel
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Notes on MySQL:

I generally store my MySQL password in an environment variable (like MYSQL_PASSWORD) and then have all of the mysql commands aliased to use the password, e.g.:

 alias mysql="mysql -p$MYSQL_PASSWORD"
 alias mysqladmin="mysqladmin -p$MYSQL_PASSWORD"

Creating a new user for a new database

   MariaDB [(none)]> CREATE DATABASE forensics wiki;
   Query OK, 1 row affected (0.00 sec)
   MariaDB [(none)]> CREATE USER 'fwiki'@'localhost' IDENTIFIED BY 'password';
   Query OK, 0 rows affected (0.09 sec)
   MariaDB [(none)]> GRANT ALL ON forensicswiki.* to 'fwiki'@'localhost';
   Query OK, 0 rows affected (0.06 sec)
   MariaDB [(none)]> FLUSH PRIVILEGES;
   Query OK, 0 rows affected (0.05 sec)
   MariaDB [(none)]> ^D
   Bye

Tuning MySQL

Look at the system load. If mysqld is not consuming 100% of the system load, then it is disk-bound, not CPU bound. You need to increase the buffers.

In the file my.cnf, try editing these values and making them larger until the system is CPU bound:

 key_buffer              = 8192M
 innodb_buffer_pool_size = 1024M
 sort_buffer_size = 100M
 read_buffer_size = 100M
 read_rnd_buffer_size = 100M
 myisam_sort_buffer_size = 100M
 query_cache_size = 1024M
 # Try number of CPU's*2 for thread_concurrency
 thread_concurrency = 8

Try these commands:

 mysql> SHOW INNODB STATUS\G

See also:

General

Useful admin commands
 mysqladmin shutdown

Linux

Restart MySQL:

 sudo /etc/init.d/mysql restart