MySQL n'est pas mon truc, mais je dois affiner l'un de nos serveurs.
Voici les exigences / spécifications:
- Le serveur MySQL n'a qu'une seule base de données significative
- Nous n'avons qu'un "type" d'application connecté, et pas beaucoup d'instances en même temps y sont connectées: au plus 15. (ces applications sont des bots XMPP)
- Ces applications ont une entrée / sortie non bloquante, ce qui signifie qu'elles n'attendent jamais sur le serveur de base de données et continuent de traiter les demandes entrantes pendant le traitement des requêtes de base de données. Cela implique que parfois une instance de cette application peut avoir plusieurs (beaucoup!) Connexions au serveur de base de données (spécialement si certaines requêtes sont lentes)
- Toutes les requêtes utilisent des indices
- Notre machine hôte exécute uniquement MySQL. Il s'agit d'une instance Xen (@slicehost) avec 2 Go de RAM.
- Nous utilisons la table InnoDB car nous avons besoin de quelques transactions de base, mais nous pourrions probablement passer à MyISAM si cela avait un réel impact sur les performances.
Comme il est configuré en ce moment, notre serveur MySQL commence lentement à manger toute la mémoire disponible (nous utilisons collectd, voici un graphique). À un moment donné (après quelques jours / semaines), il cesse d'exécuter des requêtes (il s'est arrêté cette nuit pendant 2 heures, et j'ai dû redémarrer le serveur MySQL: voir 2ème image):
(désolé, les nouveaux utilisateurs ne peuvent pas publier d'images, et seulement 1 hyperlien: /)
Hebdomadaire: http://i27.tinypic.com/6ticyv.jpg
Aujourd'hui: i31.tinypic.com/ir53yg.png
Voici notre my.cnf actuel
#
# 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/
Voici un vidage de requêtes lentes:
$ 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'
Définition de table pour les flux:
+---------------------+--------------+------+-----+---------------------+----------------+
| 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 | |
+-------+------------+--------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+
Réponses:
Vous ne devriez probablement pas considérer MyISAM, INNODB fonctionnera pour vous. MyISAM est peut-être plus rapide en ce qui concerne
SELECTmais (par exemple) il verrouille votre tableau complet sur les mises à jour.Quant à INNODB:
innodb_buffer_pool_size(nous utilisons environ 60 à 70% de notre mémoire)innodb_log_file_sizeinnodb_log_buffer_sizeinnodb_flush_log_at_trx_commitinnodb_thread_concurrencyinnodb_flush_method=O_DIRECTinnodb_file_per_tableExcellentes lectures:
A côté:
EXPLAINpour m'assurer que l'index est vraiment utiliséla source
J'ai trouvé que MySQLTuner était très efficace dans le passé - il peut faire des suggestions judicieuses pour des changements de configuration basés sur l'utilisation de votre serveur. Il est basé sur le script tuning-primer , qui vaut également la peine d'être essayé.
la source
Votre application libère-t-elle les connexions au pool lorsqu'elle a terminé son travail?
la source
Si vous pouvez remplacer les clauses where par des ID spécifiques (en supposant qu'il n'y en a pas beaucoup), cela pourrait accélérer ces mises à jour.
L'utilisation de quelque chose comme la recherche de sphinx que vous pouvez facilement regrouper pour trouver des éléments à l'avance vous aidera. J'ai entendu dire qu'il pouvait retourner des recherches plus rapidement que mysql ne savait qu'il avait des index.
http://www.sphinxsearch.com/
la source
feeds.urlIN (NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL)) .. .. OERE (feeds.urlIN ('S', 'S'))) .. Ceux pourrait être plus cher que de trouver les identifiants entiers via sphinx en premier et en utilisant sphinx, vous pouvez facilement transférer la charge vers un autre serveur en vous souciant des configurations maître-esclave et des retards dans le journal de bin.Vérifiez à nouveau les requêtes qui prennent autant de temps. Les tables sont-elles correctement indexées?
Vous pouvez également exécuter MySQL Tuner pour affiner vos paramètres mysql.
la source