Дорога в совершенство

При переносе веб сервера на виртуальный - встала задача по оптимизации и увеличению быстройдействия! В связи с этим открываю цикл статей по повышению производительности. 
part 1 mysql.

Правим конфиг:
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
# Here is entries for some specific programs
# The following values assume you have at least 32M ram
# This was formally known as [safe_mysqld]. Both versions are currently parsed.
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
#
# * Basic Settings
#
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
language = /usr/share/mysql/english
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
#
# * Fine Tuning
#
key_buffer = 512M
max_allowed_packet = 16M
thread_stack = 128K
thread_cache_size = 64
read_rnd_buffer_size = 16M
sort_buffer_size = 16M
read_buffer_size = 1M
myisam_sort_buffer_size = 32M
max_heap_table_size = 32M
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover = BACKUP
max_connections = 4096
table_cache = 1024
thread_concurrency = 10
#
# * Query Cache Configuration
#
query_cache_limit = 1M
query_cache_size = 128M
#
# * Temp Tables Configuration
max_heap_table_size = 64M
tmp_table_size = 64M
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
log = /var/log/mysql/mysql.log
log_slow_queries = /var/log/mysql/mysql-slow.log
long_query_time = 2
log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
#server-id = 1
#log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db = include_database_name
#binlog_ignore_db = include_database_name
#
# * BerkeleyDB
#
# Using BerkeleyDB is now discouraged as its support will cease in 5.1.12.
skip-bdb
#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
# You might want to disable InnoDB to shrink the mysqld process by circa 100MB.
#skip-innodb
#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
#no-auto-rehash # faster start of mysql but no tab completition
[isamchk]
key_buffer = 32M

Смотрим работает ли кэш
mysql> SHOW VARIABLES LIKE 'query_cache_%';
+------------------------------+----------+
| Variable_name | Value |
+------------------------------+----------+
| query_cache_limit | 1048576 |
| query_cache_min_res_unit | 4096 |
| query_cache_size | 67108864 |
| query_cache_type | ON |
| query_cache_wlock_invalidate | OFF |
+------------------------------+----------+
5 rows in set (0.01 sec)

Далее смотрим что получается по тестам!!!!

Смотрим индексы и можно ли их поместить в ОЗУ
debSrv01:/var/lib/mysql# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3734
Server version: 5.0.51a-24+lenny5 (Debian)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> show variables like 'datadir';
+---------------+-----------------+
| Variable_name | Value |
+---------------+-----------------+
| datadir | /var/lib/mysql/ |
+---------------+-----------------+
1 row in set (0.00 sec)
mysql> quit
Bye
debSrv01:/var/lib/mysql# cd /var/lib/mysql/
debSrv01:/var/lib/mysql#
debSrv01:/var/lib/mysql# du -ch */*.MYI
много слов ...
27M итого

Это значит что 27 метров - это у нас индексы. Параметр в My.conf отвечающий за индексы - key_buffer_size - сделаем по больше)))

Теперь следующее - прежде чем попасть в кэш индекс считывается в диска.
debSrv01:/var/lib/mysql# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3788
Server version: 5.0.51a-24+lenny5 (Debian)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> show global status like 'key_read%';
+-------------------+----------+
| Variable_name | Value |
+-------------------+----------+
| Key_read_requests | 21883724 |
| Key_reads | 21689 |
+-------------------+----------+
2 rows in set (0.00 sec)

Key_read_requests – чтения из памяти.
Key_reads – чтение с дисков

Для определения процента запроса к диску следует считать по следующей формуле:

100 - (Key_read_requests*100)/(Key_read_requests+Key_reads) = приблизительно меньше 0,1 - это хорошо чем ближе к нулю тем лучше

При работе с таблицей mysql выполняет блокировку таблицы. Смотрим задержки при блокировке:
mysql> show status like 'Table_locks_%';
+-----------------------+-------+
| Variable_name | Value |
+-----------------------+-------+
| Table_locks_immediate | 60383 |
| Table_locks_waited | 9 |
+-----------------------+-------+
2 rows in set (0.00 sec)
Чем ниже Table_locks_waited - тем лучше. Пока у нас всё хорошо.

Вам это будет интересно!

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