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linux:mysql (lu 77249 fois)
Table des matières
MySQL
Optimisation
wget --no-check-certificate https://raw.githubusercontent.com/major/MySQLTuner-perl/master/mysqltuner.pl perl mysqltuner.pl
Y’a plus qu’a corriger les valeurs des variables qu’il suggère et faire un restart de mysql ;)
- http://hackmysql.com/mysqlreport - script
A voir le paquet php5-mysqlnd qui est un client mysql natif qui est optimisé par mysql pour mysql
Quelques commandes
Pour voir toutes les variables
mysqladmin variables -p mysql> show variables; mysql> show global variables like 'log_output';
Pour modifier une variable global
mysql> set global max_connections=500;
Pour voir les status
mysql> show status;
Pour vérifier vos fichiers de config avant de redémarrer le service mysql
mysqld --help
ou
mysqld --verbose --help | head
Process list
mysql>show processlist;
Kill process
mysql>kill "number from first col";
Sauvegarder
Sauvegarder une base
mysqldump -u user -p nom_de_la_base > backup.sql
Sauvegarder toutes les tables avec un prefix
mysqldump -h hostname -u user -p $(mysql nom_de_la_base -h hostname -u user -p -Bse 'show tables like"phpbb\_%"') > dump_phpbb_.sql
La bonne pratique en prod est d’utiliser les options suivantes:
mysqldump -u USER -p --single-transaction --quick --lock-tables=false --all-databases (or) DATABASE | gzip > OUTPUT.sql.gz
- –quick : This option is useful for dumping large tables. It forces mysqldump to retrieve rows for a table from the server a row at a time rather than retrieving the entire row set and buffering it in memory before writing it out
- –single-transaction : This option sets the transaction isolation mode to REPEATABLE READ and sends a START TRANSACTION SQL statement to the server before dumping data. It is useful only with transactional tables such as InnoDB, because then it dumps the consistent state of the database at the time when START TRANSACTION was issued without blocking any applications.
- –lock-tables=false : option stops MyISAM tables (if they exsit) being locked during the backup
Sauvegarder une table avec des conditions WHERE
# Dump only the rows with the id column bigger than 500 mysqldump my_db_name my_table_name --where="id > 500" > my_backup.sql # Dump only the rows with the created_at column in the given interval mysqldump my_db_name my_table_name --where="date between '2020-09-01' and '2020-09-30'" > my_backup.sql
Restaurer
mysql -u user -p nom_de_la_base < backup.sql
Script PERL pour extraire une table d’un dump SQL
#!/usr/bin/perl -s -wnl #extract a single table from a mysql dump BEGIN { $table or warn "Usage: $0 -table=TABLE_TO_EXTRACT mysqldumpfile.sql" and exit 1; } /^DROP TABLE IF EXISTS `$table`/ .. /^UNLOCK TABLES;$/ and print;
Pour automatiser la connexion a mysql et ne pas avoir à taper de mot de passe, créer un fichier ~/.my.cnf
[client] user=root password=somepassword
Logguer les requêtes en temps réel ponctuellement
Se connecter à mysql
mysql -h localhost -u root -p
Vérifier la config des logs
mysql> show global variables like 'log_output'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_output | FILE | +---------------+-------+ 1 row in set (0.00 sec) mysql> show global variables like 'general_log_file'; +------------------+----------------------------+ | Variable_name | Value | +------------------+----------------------------+ | general_log_file | /var/run/mysqld/mysqld.log | +------------------+----------------------------+ 1 row in set (0.00 sec) mysql> show global variables like 'general_log'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | general_log | OFF | +---------------+-------+ 1 row in set (0.00 sec)
Activer les logs
mysql> set global general_log='ON'; Query OK, 0 rows affected (0.04 sec)
Désactiver les logs
mysql> set global general_log='OFF'; Query OK, 0 rows affected (0.02 sec)
Puis consulter votre fichier de log (ex:/var/run/mysqld/mysqld.log)
Faire un backup via un script php
<?php $host = 'localhost'; $db = 'maBase'; $password = 'p4ssW0rD'; $user = 'root'; echo "Votre base est en cours de sauvegarde....... "; system("mysqldump --host=$host --user=$user --password=$password $db > $db.sql"); echo "C'est fini. Vous pouvez récupérer la base par FTP"; ?>
Plein d’exemples de codes de backup et restauration sur ⇒ http://vitobotta.com/smarter-faster-backups-restores-mysql-databases-with-mysqldump/
Un autre script dans les paquets automysqlbackup https://www1.zonewebmaster.eu/serveur-debian-mysql:automysqlbackup
Percona XtraBackup
Permet des backups à chaud sans perte en copiant directement les fichiers de mysql et en appliquant les transactions en cours.
Les slow query
Afin d’identifier les requêtes qui prennent du temps, activer les slow_query
log_slow_queries = /var/log/mysql/mysql-slow.log long_query_time = 1 # pour logguer les requêtes qui prennet plus d'une seconde
Ensuite, utiliser l’utilitaire mysqldumpslow pour analyser le log.
# mysqldumpslow /var/log/mysql/mysql-slow.log Reading mysql slow query log from /var/log/mysql/mysql-slow.log Count: 8 Time=11.45s (91s) Lock=0.00s (0s) Rows=2.1 (17), INF[INF]@localhost select `process_id` from `dashboard_log` left join `dashboard_process` on `process_id` = `dashboard_process`.`id` where `dashboard_process`.`id` is null group by `process_id` order by `process_id` asc Count: 2 Time=7.05s (14s) Lock=0.00s (0s) Rows=1.0 (2), zabbix[zabbix]@localhost SELECT hu.itemid,AVG(hu.value) AS avg,MIN(hu.value) AS min,MAX(hu.value) AS max,MAX(hu.clock) AS clock FROM history_uint hu WHERE hu.itemid='S' AND hu.clock>='S' AND hu.clock<='S' GROUP BY hu.itemid Count: 1 Time=5.43s (5s) Lock=0.00s (0s) Rows=557.0 (557), root[root]@localhost SHOW TABLE STATUS Count: 8 Time=4.34s (34s) Lock=0.00s (0s) Rows=2.1 (17), INF[INF]@localhost select `process_id` from `dashboard_events` left join `dashboard_process` on `process_id` = `dashboard_process`.`id` where `dashboard_events`.`deleted_at` is null and `dashboard_process`.`id` is null group by `process_id` order by `process_id` asc Count: 11 Time=1.27s (13s) Lock=0.00s (0s) Rows=1.0 (11), INF[INF]@localhost select count(*) as aggregate from `dashboard_log` where `process_id` = 'S' Count: 11 Time=1.08s (11s) Lock=0.00s (0s) Rows=59.0 (649), INF[INF]@localhost SELECT B.* FROM ( SELECT MAX( started_at ) as started_at, process_id, `order` FROM dashboard_events D INNER JOIN dashboard_page_process C USING ( process_id ) where page_id=N GROUP BY process_id ) A INNER JOIN dashboard_events B USING (started_at,process_id) ORDER BY A.order Count: 1 Time=1.03s (1s) Lock=0.00s (0s) Rows=2.0 (2), INF[INF]@localhost select `dashboard_events`.`id` as `id`, `etat`, `etape`, `process_id`, `started_at`, `updated_at`, `commentaire`, `erreur`, `nbr_log` from `dashboard_events` left join `dashboard_process` on `dashboard_events`.`process_id` = `dashboard_process`.`id` where `dashboard_events`.`deleted_at` is null and `etape` < 'S' order by `created_at` asc
InnoDB
Une requête intégressante
SHOW ENGINE INNODB STATUS
La commande innotop permet de faire comme htop avec beaucoup d’info sur ce qu’il se passe sur innodb
innotop
Partition
Sur le lien ci-dessous, des scripts permettant d’automatiser la création et la purge de partition de type date
⇒ http://www.geoffmontee.com/automatic-partition-maintenance-in-mysql-and-mariadb-part-3/
Erreur
Après avoir lancé une optimization puis violemment killé la requete en cours, la table était inaccessible …
Starting MySQL database server: mysqld. Checking for corrupt, not cleanly closed and upgrade needing tables.. ERROR 144 (HY000) at line 1: Table 'dashboard_log' is marked as crashed and last (automatic?) repair failed
Se placer dans le bon répertoire
cd /var/lib/mysql/MA_BDD
# myisamchk MA_TABLE Checking MyISAM file: MA_TABLE Data records: 654724 Deleted blocks: 0 myisamchk: warning: Table is marked as crashed and last repair failed - check file-size myisamchk: warning: Size of indexfile is: 275469312 Should be: 25405440 - check record delete-chain - check key delete-chain - check index reference - check data record references index: 1 - check data record references index: 2 - check data record references index: 3 - check record links myisamchk: error: Record-count is not ok; is 5773841 Should be: 654724 myisamchk: warning: Found 484145612 deleted space. Should be 0 myisamchk: warning: Found 1581466 deleted blocks Should be: 0 myisamchk: warning: Found 8799790 key parts. Should be: 654724 MyISAM-table 'MA_TABLE' is corrupted Fix it using switch "-r" or "-o"
# myisamchk -r -v MA_TABLE - recovering (with sort) MyISAM-table 'MA_TABLE' Data records: 654724 - Fixing index 1 - Searching for keys, allocating buffer for 147793 keys - Merging 5773841 keys - Last merge and dumping keys - Fixing index 2 - Searching for keys, allocating buffer for 139720 keys - Merging 5773841 keys - Last merge and dumping keys - Fixing index 3 - Searching for keys, allocating buffer for 2604 keys - Merging 5773841 keys - Last merge and dumping keys Data records: 5773841
Ça remarche ! et même à chaud sans redémarrer mysql ! J’ai même l’impression que ça a été plus rapide de faire cette manip que d’attendre la fin de la requête d’optimisation…
Autre cas un peu plus complexe ou il a fallu rajouté un –force pour que ça passe. 30 minutes environ de traitement et ça remarche.
# myisamchk statistiques Checking MyISAM file: statistiques Data records: 43197952 Deleted blocks: 0 myisamchk: warning: Table is marked as crashed and last repair failed myisamchk: warning: 1 client is using or hasn't closed the table properly - check file-size myisamchk: warning: Size of indexfile is: 2134406144 Should be: 1024 - check record delete-chain - check key delete-chain - check index reference - check data record references index: 1 myisamchk: Unknown error 126 myisamchk: error: Can't read indexpage from filepos: -1 - check record links myisamchk: error: Wrong bytesec: 0-0-0 at linkstart: 10578706084 MyISAM-table 'statistiques' is corrupted Fix it using switch "-r" or "-o" # myisamchk -r -v statistiques - recovering (with sort) MyISAM-table 'statistiques' Data records: 43197952 myisamchk: error: Can't create new tempfile: 'statistiques.TMD' MyISAM-table 'statistiques' is not fixed because of errors Try fixing it by using the --safe-recover (-o), the --force (-f) option or by not using the --quick (-q) flag # myisamchk -f -r -v statistiques - recovering (with sort) MyISAM-table 'statistiques' Data records: 43197952 - Fixing index 1 - Searching for keys, allocating buffer for 102782 keys Wrong bytesec: 0- 0- 0 at 10578706084; Skipped Wrong bytesec: 0- 0- 0 at 10578706104; Skipped Wrong bytesec: 0- 0- 0 at 10578706124; Skipped Wrong bytesec: 0- 0- 0 at 10578706144; Skipped Wrong bytesec: 0- 0- 0 at 10578706164; Skipped Wrong bytesec: 0- 0- 0 at 10578706184; Skipped Wrong bytesec: 0- 0- 0 at 10578706204; Skipped Wrong bytesec: 0- 0- 0 at 10578706224; Skipped Wrong bytesec: 0- 0- 0 at 10578706244; Skipped Wrong bytesec: 0- 0- 0 at 10578706264; Skipped Wrong bytesec: 0- 0- 0 at 10578706284; Skipped Wrong bytesec: 0- 0- 0 at 10578706304; Skipped Wrong bytesec: 0- 0- 0 at 10578706324; Skipped Wrong bytesec: 0- 0- 0 at 10578706344; Skipped Wrong bytesec: 0- 0- 0 at 10578706364; Skipped Wrong bytesec: 0- 0- 0 at 10578706384; Skipped Wrong bytesec: 0- 0- 0 at 10578706404; Skipped Wrong bytesec: 0- 0- 0 at 10578706424; Skipped - Merging 43197952 keys - Last merge and dumping keys - Fixing index 2 - Searching for keys, allocating buffer for 94325 keys - Merging 43197952 keys - Last merge and dumping keys - Fixing index 3 - Searching for keys, allocating buffer for 16873 keys - Merging 43197952 keys - Last merge and dumping keys - Fixing index 4 - Searching for keys, allocating buffer for 115510 keys - Merging 43197952 keys - Last merge and dumping keys - Fixing index 5 - Searching for keys, allocating buffer for 66644 keys - Merging 43197952 keys - Last merge and dumping keys
Strict Mode
Bon à savoir si jamais vous copiez des dates en 0000-00-00 et que vous avez une erreur
SQLSTATE[22007]: Invalid datetime format: 1292 Incorrect date value: '0000-00-00' for column...
Strict mode affects whether the server permits ‘0000-00-00’ as a valid date: If strict mode is not enabled, ‘0000-00-00’ is permitted and inserts produce no warning. If strict mode is enabled, ‘0000-00-00’ is not permitted and inserts produce an error, unless IGNORE is given as well. For INSERT IGNORE and UPDATE IGNORE, ‘0000-00-00’ is permitted and inserts produce a warning.
Log binaire
Utiliser des log binaire pour mettre à jour une base de données distante après avoir fait un mysqldump
Vérifier si les log binaires sont activé
MariaDB [(none)]> SHOW BINARY LOGS; +------------------+-----------+ | Log_name | File_size | +------------------+-----------+ | mysql-bin.000001 | 328 | +------------------+-----------+ 1 row in set (0.000 sec) MariaDB [(none)]> show variables like 'log_bin%'; +---------------------------------+--------------------------------+ | Variable_name | Value | +---------------------------------+--------------------------------+ | log_bin | ON | | log_bin_basename | /var/log/mysql/mysql-bin | | log_bin_compress | OFF | | log_bin_compress_min_len | 256 | | log_bin_index | /var/log/mysql/mysql-bin.index | | log_bin_trust_function_creators | OFF | +---------------------------------+--------------------------------+ 6 rows in set (0.001 sec)
Si non
mysql> SHOW BINARY LOGS; ERROR 1381 (HY000): You are not using binary logging
Pour activer dans le cas de mariaDB
vi /etc/mysql/mariadb.conf.d/50-server.cnf
Décommenter la ligne
log_bin = /var/log/mysql/mysql-bin.log
et restarter mariaDB
systemctl restart mariadb.service
Vos fichiers de log binaires sont maintenant stocké dans /var/log/mysql/
mysqlbinlog permet de lire les fichiers de log binaire et de générer une sortie sql
# mysqlbinlog mysql-bin.000001 mysqlbinlog: unknown variable 'default-character-set=utf8mb4' ---------- Si vous avez ce message d'erreur, utilisez l'option suivante # mysqlbinlog --no-defaults mysql-bin.000001
Filtre possible:
–database=ma_baseou-d ma_base–start-datetime=“2019-09-09 12:15:00”supérieur ou égal à cette date–stop-datetime=“2019-12-24 13:15:00”inférieur à cette date–start-position=Ncommence à la position N–stop-position=Ns’arrête à la position N
example de restauration
mysqlbinlog /var/log/mysql/mysql-bin.[0-9]* | mysql -u root -p
mysqlbinlog --no-defaults --start-datetime="2019-09-09 12:15:00" /var/log/mysql/mysql-bin.[0-9]* | mysql -u root -p
Par défaut, mysql s’arrête dès la 1ère erreur (par ex: duplicate entry), pour continuer après une erreur, ajouté l’option -f
mysqlbinlog --no-defaults --start-datetime="2019-09-09 12:15:00" /var/log/mysql/mysql-bin.[0-9]* | mysql -u root -p -f
Auto increment
On peut réinitialiser la valeur de l’auto increment d’un id avec la requete
ALTER TABLE `users` AUTO_INCREMENT = 1;
Mysql prendra automatiquement le max(id) + 1
Pour réinitialiser complètement une colonne d’id
ALTER TABLE `users` DROP `id`; ALTER TABLE `users` AUTO_INCREMENT = 1; ALTER TABLE `users` ADD `id` INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST;
Si votre id est utilisé dans d’autres tables, il convient de définir les clés étrangères sur les autres tables avec l’option ON UPDATE CASCADE plutot que l’option par défaut ON UPDATE NO ACTION
SET @COUNT = 0; UPDATE `users` SET `users`.`id` = @COUNT:= @COUNT + 1; ALTER TABLE `users` AUTO_INCREMENT = 1;
linux/mysql.txt · Dernière modification: 14-02-2023 11:39 de edmc73
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