MySQLサーバーを微調整するには?


8

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、同時に接続されているインスタンスは多くありません。最大で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ノンブロッキングIOがあります。つまり、DBサーバーで「待機」せずに、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!)接続を持つことができ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を備えた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、パフォーマンスに実際に影響がある場合は、おそらくMyISAMに切り替えることができます。

現在設定されているため、MySQLサーバーは利用可能なメモリをすべて徐々に消費し始めます(ここでは、collectdを使用しています。ここにグラフがあります)。ある時点(数日/週後)でクエリの実行が停止します(今夜は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番目の画像を参照してください)。

(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:/)

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/

これは遅いクエリのダンプです:

$ 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      |         | 
+-------+------------+--------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+

エラーログは何を言っていますか?
shantanuo 2011年

回答:


12

あなたはおそらくMyISAMを考慮すべきではありません、INNODBがあなたのために働きます。MyISAMはおそらくそれより高速ですSELECT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 (私達は私達の記憶のおよそ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に切り替える(同じAPI)
  • perconaビルドを使用します(Googleから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:

余談ですが:

  • これを実行するには、2 GBのスライスでは不十分です。
  • さらに私はスライスホストのストレージがかなり遅いことを発見しました(ioは要因です)
  • 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可能性があります(RAM制限のため)
  • すべてのクエリを実行EXPLAINして、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

素晴らしい反応!現時点では、データベースのサイズは61Mです...ですから、ステートメントを信じるとしたらDB =〜RAM; 十分なRAMがあります。ストレージは確かに遅いと思います(おそらく仮想化されているためです)。リンクを読みます。ありがとう!
Julien Genestoux 08

(そして、ええ、私はEXPLAINを通じてすべてのクエリを実行し、それらはすべてインデックスを使用しています)
Julien Genestoux 2009

ジュリアンさん-まず、この辺りで回答に投票します。;-)次に、MySQLがRAMを使用していない場合は、RAMを用意するだけでは意味がありません。設定を再確認して、使用されるようにしてください。
ティル

ええ、それはまさに私の助けが必要なところです;)私はMySQLがそれを使用していると思います。(そして、実際には多すぎる!、ある時点でサーバーがRAMを使い果たすようになるためです)。61Mの場合、DBのサイズはどうして2GBのRAMを「食べる」のですか?
Julien Genestoux 08

「最悪」のクエリのテーブル定義を追加できますか?
ティル

2

MySQLTunerは過去に非常に効果的であることがわかりました。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。これは、チューニングプライマースクリプトに基づいています。これも試してみる価値があります。


1

アプリは、プールへの接続が完了するとプールへの接続を解放しますか?


いいえ、実際に彼らと一緒に行われることは決してないので。これは、接続間でアプリが「停止」するWebアプリのようなものではありません。
Julien Genestoux 2009

0

where句を特定のIDに置き換えることができる場合(多くはないものと想定)、こ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と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/


申し訳ありませんが、意味がわかりませんか?データベースでの検索は行っていません...
Julien Genestoux、2009

あなたは以下の通りです。..( feedsurl.. .. WHERE IN(NULL、NULL、NULL、NULL、NULL、NULL、NULL、NULL、NULL))( 。feeds。。urlこれらIN( 'S'、 'S'))最初にsphinxを介して整数IDを見つけるよりもコストがかかる可能性があり、sphinxを使用すると、マスター/スレーブのセットアップとビンログの遅延を心配して、負荷を別のサーバーに簡単にプッシュできます。
マークL

feeds.urlはインデックスです。主キーはインデックスよりも高速ですか?
Julien Genestoux 2009

VARCHAR(10)の代わりに(私が想定しているように)整数であるか、またはそのようなものである場合、そうです、整数はより少ないスペースを使用し、mysqlはインデックステーブルでそれをより速く見つけることができます。
マークL

しかし、それは本当に限界ではないでしょうか?
Julien Genestoux、2009

0

時間のかかるクエリをもう一度確認してください。テーブルは適切に索引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。


ええ、サーバーがブロックするときに起こります。もう一度、すべてのクエリをチェックしました。すべてのクエリはインデックスを使用しています。(+最も遅いクエリはINSERTクエリでもあります...インデックスとは関係ありません、AFAIK)
Julien Genestoux
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