MySQLサーバーを微調整する方法は？

Question

MySQLは私のものではありませんが、サーバーの1つを微調整する必要があります。

要件/仕様は次のとおりです。

MySQLサーバーには重要なデータベースが1つだけあります
接続されているアプリケーションの「タイプ」は1つだけであり、同時に接続されているインスタンスは多くありません。最大15です（これらのアプリケーションはXMPPボットです）。
これらのアプリケーションには非ブロッキングIOがあります。つまり、DBサーバーで「待機」することはなく、DBクエリの処理中に着信要求の処理を続行します。これは、このアプリケーションの1つのインスタンスがデータベースサーバーへの複数の（多くの！）接続を持つ可能性があることを意味します（特に一部のクエリが遅い場合）
- すべてのクエリはインデックスを使用しています
- ホストマシンはMySQLのみを実行します。これは、2GBのRAMを搭載したXenインスタンス（@slicehost）です。
- 基本的なトランザクションが必要なため、InnoDBテーブルを使用しますが、これがパフォーマンスに実際に影響を与える場合は、おそらくMyISAMに切り替えることができます。

現在構成されているため、MySQLサーバーは使用可能なすべてのメモリをゆっくりと消費し始めます（collectdを使用します。これがグラフです）。ある時点（数日/週後）で、クエリの実行が停止します（この夜、2時間停止し、MySQLサーバーを再起動する必要がありました：2番目の画像を参照）：

（申し訳ありませんが、新しいユーザーは画像を投稿できません。ハイパーリンクは1つだけです：/）

毎週： http://i27.tinypic.com/6ticyv.jpg
今日：i31.tinypic.com/ir53yg.png

これが現在のmy.cnfです

# # The MySQL database server configuration file. # # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [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 # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # 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. # yann changed this on a friday balbla #bind-address = 127.0.0.1 bind-address = 0.0.0.0 # # * Fine Tuning # key_buffer = 16M max_allowed_packet = 16M thread_stack = 128K thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP max_connections = 2000 #table_cache = 64 #thread_concurrency = 10 # # * Query Cache Configuration # query_cache_limit = 1M query_cache_size = 16M # # * 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 # # Error logging goes to syslog. This is a Debian improvement :) # # Here you can see queries with especially long duration log_slow_queries = /var/log/mysql/mysql-slow.log long_query_time = 3 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 # Fine tunig added by JG on 06/03 based on http://www.mysqlperformanceblog.com/2007/11/01/innodb-performance-optimization-basics/ innodb_buffer_pool_size = 1G #innodb_log_file_size = 256M innodb_log_buffer_size = 4M innodb_flush_log_at_trx_commit = 2 innodb_thread_concurrency = 8 innodb_flush_method = O_DIRECT innodb_file_per_table transaction-isolation = READ-COMMITTED innodb_table_locks = 0 # # * Federated # # The FEDERATED storage engine is disabled since 5.0.67 by default in the .cnf files # shipped with MySQL distributions (my-huge.cnf, my-medium.cnf, and so forth). # skip-federated # # * 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 = 16M # # * NDB Cluster # # See /usr/share/doc/mysql-server-*/README.Debian for more information. # # The following configuration is read by the NDB Data Nodes (ndbd processes) # not from the NDB Management Nodes (ndb_mgmd processes). # # [MYSQL_CLUSTER] # ndb-connectstring=127.0.0.1 # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/

遅いクエリのダンプは次のとおりです。

$ mysqldumpslow /var/log/mysql/mysql-slow.log Reading mysql slow query log from /var/log/mysql/mysql-slow.log Count: 5 Time=3689348814741910528.00s (-1s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] SET insert_id=N; INSERT IGNORE INTO `feeds` (`url`) VALUES ('S') Count: 41 Time=1349761761490942720.00s (-1s) Lock=0.12s (5s) Rows=253.0 (10373), superfeeder[superfeeder]@localhost SHOW GLOBAL STATUS Count: 25 Time=737869762948382080.00s (-1s) Lock=0.00s (0s) Rows=18.1 (452), superfeeder[superfeeder]@[172.21.1.158] SELECT `feeds`.* FROM `feeds` WHERE (`fetch_session_id` = 'S') Count: 12952 Time=1424239042133230.25s (-1s) Lock=0.00s (1s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] SET insert_id=N; INSERT IGNORE INTO `entries` (`chunks`, `time`, `feed_id`, `unique_id`, `link`, `chunk`) VALUES ('S', 'S', N, 'S', 'S', 'S') Count: 29 Time=656.55s (19040s) Lock=5.28s (153s) Rows=0.8 (23), superfeeder[superfeeder]@[172.21.1.175] select salt,crypted_password from users where login='S' Count: 39 Time=505.23s (19704s) Lock=2.41s (94s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] DELETE FROM `feeds` WHERE (url LIKE 'S') Count: 2275 Time=502.50s (1143184s) Lock=3.48s (7922s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] UPDATE `feeds` SET `next_fetch` = 'S', `fetch_session_id` = 'S' WHERE (`next_fetch` < 'S') LIMIT N Count: 1 Time=443.00s (443s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN (NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL)) Count: 14 Time=289.43s (4052s) Lock=0.71s (10s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN ('S','S')) Count: 2 Time=256.00s (512s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN (NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL)) Count: 1 Time=237.00s (237s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN ('S')) Count: 24 Time=191.58s (4598s) Lock=1.12s (27s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`id` = 'S') Count: 5 Time=144.20s (721s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN (NULL,NULL,NULL)) Count: 1 Time=101.00s (101s) Lock=1.00s (1s) Rows=1.0 (1), superfeeder[superfeeder]@[172.21.1.158] SELECT * FROM `users` WHERE (`login` = 'S') LIMIT N Count: 79 Time=35.51s (2805s) Lock=2.52s (199s) Rows=0.2 (12), superfeeder[superfeeder]@[172.21.1.184] SELECT `feeds`.id FROM `feeds` WHERE (`feeds`.`url` = BINARY 'S' AND `feeds`.id <> N) LIMIT N Count: 1 Time=28.00s (28s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] UPDATE `feeds` SET `last_maintenance_at` = 'S', `updated_at` = 'S' WHERE `id` = N Count: 51 Time=23.51s (1199s) Lock=0.12s (6s) Rows=19.2 (981), superfeeder[superfeeder]@2hosts SELECT version FROM schema_migrations Count: 5 Time=20.60s (103s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] BEGIN Count: 65 Time=15.86s (1031s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] UPDATE `feeds` SET `last_error_message` = 'S', `period` = 'S', `last_sup_update_id` = NULL, `updated_at` = 'S', `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = 'S', `active` = 'S', `last_fetch` = 'S', `created_at` = 'S', `max_period` = 'S' WHERE (`id` = N) Count: 23 Time=11.52s (265s) Lock=0.00s (0s) Rows=231.0 (5313), superfeeder[superfeeder]@2hosts # Count: 132 Time=10.53s (1390s) Lock=0.02s (2s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] UPDATE `feeds` SET `last_error_message` = 'S', `period` = 'S', `last_sup_update_id` = NULL, `updated_at` = 'S', `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = 'S', `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N) Count: 62 Time=9.81s (608s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184] ROLLBACK Count: 151 Time=8.94s (1350s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@2hosts DELETE FROM `entries` WHERE (`time` < 'S') Count: 25 Time=8.76s (219s) Lock=0.00s (0s) Rows=1.0 (24), superfeeder[superfeeder]@[172.21.1.158] SELECT * FROM `feeds` WHERE (`url` = 'S') LIMIT N Count: 2 Time=8.50s (17s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] set SQL_AUTO_IS_NULL=N Count: 8802 Time=8.44s (74319s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] INSERT IGNORE INTO `entries` (`chunks`, `time`, `feed_id`, `unique_id`, `link`, `chunk`) VALUES ('S', 'S', N, 'S', 'S', 'S') Count: 1 Time=8.00s (8s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] INSERT IGNORE INTO `subscriptions` (`user_id`, `feed_id`) VALUES (N, N) Count: 38 Time=7.92s (301s) Lock=0.00s (0s) Rows=1.0 (38), superfeeder[superfeeder]@[172.21.1.184] SELECT count(DISTINCT `users`.id) AS count_users_id FROM `users` INNER JOIN `subscriptions` ON `users`.id = `subscriptions`.user_id WHERE ((`subscriptions`.feed_id = N)) Count: 9 Time=7.67s (69s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] INSERT IGNORE INTO `feeds` (`url`) VALUES ('S') Count: 244 Time=7.20s (1756s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] UPDATE `feeds` SET `last_error_message` = 'S', `period` = N, `last_sup_update_id` = NULL, `updated_at` = 'S', `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = N, `active` = 'S', `last_fetch` = 'S', `created_at` = 'S', `max_period` = 'S' WHERE (`id` = N) Count: 336 Time=6.85s (2301s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] UPDATE `feeds` SET `last_error_message` = 'S', `period` = N, `last_sup_update_id` = NULL, `updated_at` = 'S', `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = N, `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N) Count: 16 Time=6.38s (102s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] UPDATE `feeds` SET `last_error_message` = 'S', `period` = N, `last_sup_update_id` = NULL, `updated_at` = NULL, `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = N, `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N) Count: 122 Time=5.91s (721s) Lock=0.00s (0s) Rows=1.0 (119), superfeeder[superfeeder]@[172.21.1.158] SELECT DISTINCT `users`.* FROM `users` INNER JOIN `subscriptions` ON (`subscriptions`.`user_id` = `users`.`id`) WHERE (`subscriptions`.`feed_id` = N) Count: 299 Time=5.78s (1727s) Lock=0.00s (0s) Rows=1.0 (299), superfeeder[superfeeder]@[172.21.1.158] SELECT * FROM `feeds` WHERE (`id` = 'S') Count: 21 Time=5.48s (115s) Lock=0.00s (0s) Rows=1.0 (21), superfeeder[superfeeder]@[172.21.1.158] SELECT * FROM `subscriptions` WHERE ((`user_id` = N) AND (`feed_id` = N)) LIMIT N Count: 27 Time=5.37s (145s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] UPDATE `feeds` SET `last_error_message` = 'S', `period` = 'S', `last_sup_update_id` = NULL, `updated_at` = NULL, `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = 'S', `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N) Count: 9 Time=4.33s (39s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158] UPDATE `feeds` SET `last_error_message` = 'S', `period` = 'S', `last_sup_update_id` = NULL, `updated_at` = NULL, `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = NULL, `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N) Count: 1 Time=4.00s (4s) Lock=0.00s (0s) Rows=1.0 (1), superfeeder[superfeeder]@[172.21.1.175] select id from users where login='S' Count: 1 Time=3.00s (3s) Lock=0.00s (0s) Rows=22.0 (22), debian-sys-maint[debian-sys-maint]@localhost select concat("S", TABLE_SCHEMA, "S", TABLE_NAME, "S") from information_schema.TABLES where ENGINE="S" Count: 1056 Time=0.11s (111s) Lock=0.00s (0s) Rows=126.9 (133998), superfeeder[superfeeder]@[172.21.1.184] SELECT * FROM `feeds` WHERE (last_maintenance_at < 'S') Count: 1049 Time=0.00s (1s) Lock=0.00s (0s) Rows=3.1 (3303), superfeeder[superfeeder]@[172.21.1.184] SELECT * FROM `users` WHERE (one_week_anniversary_sent = N AND activated_at < 'S') Count: 21 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), 0users@0hosts administrator command: Ping Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), debian-sys-maint[debian-sys-maint]@localhost select count(*) into @discard from `information_schema`.`COLUMNS` Count: 8 Time=0.00s (0s) Lock=0.00s (0s) Rows=30.0 (240), superfeeder[superfeeder]@[172.21.1.184] SELECT DISTINCT `feeds`.* FROM `feeds` INNER JOIN `subscriptions` ON `feeds`.id = `subscriptions`.feed_id WHERE ((`subscriptions`.user_id = N)) AND ((`subscriptions`.user_id = N)) LIMIT N, N Count: 31 Time=0.00s (0s) Lock=0.00s (0s) Rows=1.0 (31), superfeeder[superfeeder]@2hosts SELECT count(*) AS count_all FROM `feeds` Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), debian-sys-maint[debian-sys-maint]@localhost select count(*) into @discard from `information_schema`.`TRIGGERS` Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), debian-sys-maint[debian-sys-maint]@localhost select count(*) into @discard from `information_schema`.`VIEWS` Count: 52 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.7 (34), superfeeder[superfeeder]@[172.21.1.184] SELECT * FROM `users` WHERE (`users`.`remember_token` = 'S') LIMIT N Count: 120 Time=0.00s (0s) Lock=0.00s (0s) Rows=1.0 (120), superfeeder[superfeeder]@2hosts SELECT * FROM `feeds` ORDER BY feeds.id DESC LIMIT N Count: 19 Time=0.00s (0s) Lock=0.00s (0s) Rows=15.7 (299), superfeeder[superfeeder]@2hosts SELECT count(*) AS count_all, last_http_code AS last_http_code FROM `feeds` GROUP BY last_http_code Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), debian-sys-maint[debian-sys-maint]@localhost select count(*) into @discard from `information_schema`.`ROUTINES` Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=1.0 (1), debian-sys-maint[debian-sys-maint]@localhost SELECT count(*) FROM mysql.user WHERE user='S' and password='S'

フィードのテーブル定義：

+---------------------+--------------+------+-----+---------------------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------------+--------------+------+-----+---------------------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | url | varchar(255) | YES | UNI | NULL | | | last_parse | datetime | YES | | 2009-08-10 14:51:46 | | | etag | varchar(255) | YES | | etag | | | modified | datetime | YES | | 2009-08-10 14:51:46 | | | active | tinyint(1) | YES | MUL | 1 | | | last_fetch | datetime | YES | | 2009-08-10 14:51:46 | | | next_fetch | datetime | YES | MUL | 2009-08-10 14:51:46 | | | fetch_session_id | varchar(255) | YES | MUL | | | | period | int(11) | YES | | 240 | | | hashed_content | varchar(255) | YES | | | | | streamed | tinyint(1) | YES | | 0 | | | sup_id | varchar(255) | YES | MUL | NULL | | | last_sup_update_id | varchar(255) | YES | | NULL | | | last_entry_time | datetime | YES | | 2009-08-10 14:51:46 | | | last_ping | datetime | YES | | NULL | | | last_http_code | int(11) | YES | | NULL | | | last_error_message | varchar(255) | YES | | | | | sup_url_id | int(11) | YES | MUL | NULL | | | created_at | datetime | YES | | NULL | | | updated_at | datetime | YES | | NULL | | | last_maintenance_at | datetime | YES | | 2008-08-10 21:51:50 | | | min_period | int(11) | YES | | 60 | | | max_period | int(11) | YES | | 900 | | +---------------------+--------------+------+-----+---------------------+----------------+ +-------+------------+--------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +-------+------------+--------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+ | feeds | 0 | PRIMARY | 1 | id | A | 166 | NULL | NULL | | BTREE | | | feeds | 0 | index_feeds_on_url | 1 | url | A | 166 | NULL | NULL | YES | BTREE | | | feeds | 1 | index_feeds_on_next_fetch_and_active | 1 | next_fetch | A | 1 | NULL | NULL | YES | BTREE | | | feeds | 1 | index_feeds_on_next_fetch_and_active | 2 | active | A | 1 | NULL | NULL | YES | BTREE | | | feeds | 1 | index_feeds_on_sup_id | 1 | sup_id | A | 1 | NULL | NULL | YES | BTREE | | | feeds | 1 | index_feeds_on_sup_url_id | 1 | sup_url_id | A | 1 | NULL | NULL | YES | BTREE | | | feeds | 1 | index_feeds_on_fetch_session_id | 1 | fetch_session_id | A | 1 | NULL | NULL | YES | BTREE | | +-------+------------+--------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+

Till · Accepted Answer

MyISAMを検討するべきではないでしょう。INNODBが役に立ちます。 MyISAMは、SELECTに関してはおそらく高速ですが、（たとえば）更新時にテーブル全体をロックします。

INNODBについて：

一般に、シャーディングに入る前に、常により多くのRAMを検討してください（DBのサイズ= 〜RAM）
次の変数を見てください：
- innodb_buffer_pool_size（メモリの約60〜70％を使用します）
- innodb_log_file_size
- innodb_log_buffer_size
- innodb_flush_log_at_trx_commit
- innodb_thread_concurrency
- innodb_flush_method=O_DIRECT
- innodb_file_per_table
innodbから xtradb （同じAPI）に切り替えます
perconaビルドを使用します（Googleなどのパフォーマンスパッチが含まれています）

素晴らしい読み物：

補足：

これを実行するには、2GBのスライスだけでは不十分です。
さらに、slicehostのストレージがかなり遅いことがわかりました（ioが要因です）
クラウドでは、早期にシャーディングすることが理にかなっている場合があります（RAM制限のため）
EXPLAINを介してallクエリを実行し、インデックスが実際に使用されていることを確認します

Dan · Answer

MySQLTuner は過去に非常に効果的であることがわかりました。これにより、サーバーの使用状況に基づいて構成を変更するための賢明な提案を行うことができます。 tuning-primer スクリプトに基づいており、これも試してみる価値があります。

Tom · Answer

アプリは、処理が終了したときにプールへの接続を解放しますか？

Mark L · Answer

Where句を特定のIDに置き換えることができれば（多くはないと仮定して）、それらの更新を高速化できます。

簡単にクラスター化して事前にアイテムを見つけることができるスフィンクス検索のようなものを使用すると役立ちます。 mysqlがインデックスを持っていることを知っているよりも速く検索を返すことができると聞きました。

http://www.sphinxsearch.com/

hdanniel · Answer

非常に時間がかかっているクエリをもう一度確認してください。テーブルは適切にインデックス付けされていますか？

また、 MySQL Tuner を実行して、mysql設定を微調整することもできます。