MySQLTuner (http://mysqltuner.com) представляет собой Perl скрипт,
анализирующий статистику работы MySQL сервера и на ее основе дающий
рекомендации по оптимизации настойки СУБД. И так, скачиваем сам скрипт:
wget http://mysqltuner.com/mysqltuner.pl
chmod +x mysqltuner.pl
chmod +x mysqltuner.pl
запускаем:
perl mysqltuner.pl
вас попросят ввести логин и пароль root-a. В итоге вы получите подобный результат:
——— General Statistics —————————————————
[—] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.1.56
[OK] Operating on 32-bit architecture with less than 2GB RAM
[—] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.1.56
[OK] Operating on 32-bit architecture with less than 2GB RAM
——— Storage Engine Statistics ——————————————-
[—] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[—] Data in MyISAM tables: 104M (Tables: 339)
[—] Data in InnoDB tables: 15M (Tables: 40)
[!!] Total fragmented tables: 90
[—] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[—] Data in MyISAM tables: 104M (Tables: 339)
[—] Data in InnoDB tables: 15M (Tables: 40)
[!!] Total fragmented tables: 90
——— Performance Metrics ————————————————-
[—] Up for: 16d 20h 48m 45s (2M q [1.535 qps], 84K conn, TX: 55B, RX: 429M)
[—] Reads / Writes: 43% / 57%
[—] Total buffers: 106.0M global + 9.2M per thread (500 max threads)
[!!] Allocating > 2GB RAM on 32-bit systems can cause system instability
[!!] Maximum possible memory usage: 4.6G (231% of installed RAM)
[OK] Slow queries: 0% (3/2M)
[OK] Highest usage of available connections: 6% (32/500)
[OK] Key buffer size / total MyISAM indexes: 16.0M/13.9M
[OK] Key buffer hit rate: 100.0% (65M cached / 3K reads)
[OK] Query cache efficiency: 74.4% (1M cached / 1M selects)
[!!] Query cache prunes per day: 626
[OK] Sorts requiring temporary tables: 0% (289 temp sorts / 42K sorts)
[!!] Joins performed without indexes: 52872
[OK] Temporary tables created on disk: 24% (24K on disk / 99K total)
[OK] Thread cache hit rate: 99% (32 created / 84K connections)
[!!] Table cache hit rate: 9% (305 open / 3K opened)
[OK] Open file limit used: 17% (459/2K)
[OK] Table locks acquired immediately: 99% (947K immediate / 947K locks)
[!!] InnoDB data size / buffer pool: 15.1M/8.0M
[—] Up for: 16d 20h 48m 45s (2M q [1.535 qps], 84K conn, TX: 55B, RX: 429M)
[—] Reads / Writes: 43% / 57%
[—] Total buffers: 106.0M global + 9.2M per thread (500 max threads)
[!!] Allocating > 2GB RAM on 32-bit systems can cause system instability
[!!] Maximum possible memory usage: 4.6G (231% of installed RAM)
[OK] Slow queries: 0% (3/2M)
[OK] Highest usage of available connections: 6% (32/500)
[OK] Key buffer size / total MyISAM indexes: 16.0M/13.9M
[OK] Key buffer hit rate: 100.0% (65M cached / 3K reads)
[OK] Query cache efficiency: 74.4% (1M cached / 1M selects)
[!!] Query cache prunes per day: 626
[OK] Sorts requiring temporary tables: 0% (289 temp sorts / 42K sorts)
[!!] Joins performed without indexes: 52872
[OK] Temporary tables created on disk: 24% (24K on disk / 99K total)
[OK] Thread cache hit rate: 99% (32 created / 84K connections)
[!!] Table cache hit rate: 9% (305 open / 3K opened)
[OK] Open file limit used: 17% (459/2K)
[OK] Table locks acquired immediately: 99% (947K immediate / 947K locks)
[!!] InnoDB data size / buffer pool: 15.1M/8.0M
——— Recommendations ——————————————————
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
Enable the slow query log to troubleshoot bad queries
Adjust your join queries to always utilize indexes
Increase table_cache gradually to avoid file descriptor limits
Variables to adjust:
*** MySQL’s maximum memory usage is dangerously high ***
*** Add RAM before increasing MySQL buffer variables ***
query_cache_size (> 64M)
join_buffer_size (> 2.0M, or always use indexes with joins)
table_cache (> 1024)
innodb_buffer_pool_size (>= 15M)
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
Enable the slow query log to troubleshoot bad queries
Adjust your join queries to always utilize indexes
Increase table_cache gradually to avoid file descriptor limits
Variables to adjust:
*** MySQL’s maximum memory usage is dangerously high ***
*** Add RAM before increasing MySQL buffer variables ***
query_cache_size (> 64M)
join_buffer_size (> 2.0M, or always use indexes with joins)
table_cache (> 1024)
innodb_buffer_pool_size (>= 15M)
Обратите свое внимание на рекомендации, и для лучшей работы MySQL внести предложенные изменения в my.cnf
Михаил says:
Здравствуйте. Можете объяснить следующее:
скрипт выдает
Variables to adjust:
*** MySQL’s maximum memory usage is dangerously high ***
*** Add RAM before increasing MySQL buffer variables ***
query_cache_limit (> 40M, or use smaller result sets)
tmp_table_size (> 90M)
max_heap_table_size (> 90M)
если я правильно понимаю, то необходимо уменьшить указанные параметры, верно? (но меньшее значение может сказаться при сложных запросах)
admin says:
Говорит, что MySQL уже использует опасно большое количество памяти, и необходимо увеличить память, а пока, рекомендует уменьшить некоторые параметры.