I inherited a mysql server, and so I've started with running the MySQLTuner.pl script. I am not a MySQL expert but I can see that there is definitely a mess here. I'm not looking to go after every single thing that needs fixing and tuning, but I do want to grab the major, low hanging fruit.
Total Memory on the system is: 512MB. Yes, I know it's low, but it's what we have for the time being.
Here's what the script had to say:
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
MySQL started within last 24 hours - recommendations may be inaccurate
Enable the slow query log to troubleshoot bad queries
When making adjustments, make tmp_table_size/max_heap_table_size equal
Reduce your SELECT DISTINCT queries without LIMIT clauses
Increase table_cache gradually to avoid file descriptor limits
Your applications are not closing MySQL connections properly
Variables to adjust:
query_cache_limit (> 1M, or use smaller result sets)
tmp_table_size (> 16M)
max_heap_table_size (> 16M)
table_cache (> 64)
innodb_buffer_pool_size (>= 326M)
For the variables that it recommends that I adjust, I don't even see most of them in the mysql.cnf file.
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
innodb_buffer_pool_size = 220M
innodb_flush_log_at_trx_commit = 2
innodb_file_per_table = 1
innodb_thread_concurrency = 32
skip-locking
big-tables
max_connections = 50
innodb_lock_wait_timeout = 600
slave_transaction_retries = 10
innodb_table_locks = 0
innodb_additional_mem_pool_size = 20M
user = mysql
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
skip-external-locking
bind-address = localhost
key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 4
myisam-recover = BACKUP
query_cache_limit = 1M
query_cache_size = 16M
log_error = /var/log/mysql/error.log
expire_logs_days = 10
max_binlog_size = 100M
skip-locking
innodb_file_per_table = 1
big-tables
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
[isamchk]
key_buffer = 16M
!includedir /etc/mysql/conf.d/