15-09-2021

docs/MySQL/repair.md

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+# Réparer des tables :
+
+[MySQL Server logs](https://dev.mysql.com/doc/refman/5.7/en/server-logs.html)
+
+La 1ere chose à faire en cas de problèmes est de consulter les fichiers logs. Ceux-çi sont généralement avec les tables:
+
+```bash
+#osx (Homebrew):
+
+$ cd /usr/local/var/mysql
+total 388560
+drwxr-xr-x  32 bruno  admin      1024 28 nov 16:53 .
+drwxrwxr-x  13 bruno  admin       416 16 fév  2018 ..
+-rw-rw----   1 bruno  admin     16384 28 nov 08:08 aria_log.00000001
+-rw-rw----   1 bruno  admin        52 28 nov 08:08 aria_log_control
+drwx------  48 bruno  admin      1536  1 déc 17:05 funnymac
+drwx------  53 bruno  admin      1696  1 déc 17:05 ghost_prod
+-rw-r-----   1 bruno  admin     15114 28 nov 08:08 ib_buffer_pool
+-rw-rw----   1 bruno  admin  50331648  3 déc 07:19 ib_logfile0
+-rw-rw----   1 bruno  admin  50331648 24 oct 12:51 ib_logfile1
+-rw-rw----   1 bruno  admin  79691776  3 déc 07:19 ibdata1
+-rw-rw----   1 bruno  admin  12582912 28 nov 16:53 ibtmp1
+drwx------   9 bruno  admin       288  1 déc 17:05 mgpt
+-rw-rw----   1 bruno  admin         0 24 jul  2017 multi-master.info
+drwx------  89 bruno  admin      2848  1 déc 17:05 mysql
+drwx------   3 bruno  admin        96 24 jul  2017 performance_schema
+drwx------  41 bruno  admin      1312  1 déc 17:05 phpmyadmi
+-rw-rw----   1 bruno  admin   1271878  3 déc 07:19 silverbook.home.err
+-rw-rw----   1 bruno  admin         5 28 nov 16:53 silverbook.home.pid
+```
+
+
+
+<u>Pour réparer, 2 solutions:</u>
+
+ **1) REPAIR TABLE:** 
+
+- ne nécessite pas l’arrêt de MySQL
+- uniquement base MyISAM
+
+
+
+```bash
+MariaDB [zenphoto]> REPAIR TABLE _tags;
++----------------+--------+----------+---------------------------------------------------------+
+| Table          | Op     | Msg_type | Msg_text                                                |
++----------------+--------+----------+---------------------------------------------------------+
+| zenphoto._tags | repair | note     | The storage engine for the table doesn't support repair |
++----------------+--------+----------+---------------------------------------------------------+
+
+1 row in set (0.006 sec)
+```
+
+Si l’erreur persiste, **vider le cache** (Flush all cache)
+
+
+
+  **2) mysqlcheck -r:** 
+
+- nécessite un arrêt du service MySQL 
+
+- uniquement base MyISAM
+
+
+
+[MyISAM](https://dev.mysql.com/doc/refman/5.5/en/myisam-storage-engine.html): 
+
+```bash
+$ mysqlcheck -u root -ppassword -r zenphoto .comments
+
+zenphoto..comments                                 OK
+```
+
+
+
+[InnoDB](https://dev.mysql.com/doc/refman/5.5/en/innodb-storage-engine.html): 
+
+```bash
+$ mysqlcheck -u root -ppassword -r zenphoto _tags
+
+zenphoto._tags
+
+note     : The storage engine for the table doesn't support repair
+```
+
+Pour les tables InnoDB, il faut [forcer la récupération](https://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html):
+
+    1) Arrêter **mysqld**:
+
+    2) Sauvegarder **mysql**:
+
+```bash
+#Linux
+/var/lib/mysql/
+
+#osx (Homebrew)
+/usr/local/var/mysql/
+```
+
+    3) Ajouter au fichier de configuration MySQL my.cnf:
+
+```
+#osx (Homebrew): /usr/local/etc/my.cnf
+
+[mysqld]
+innodb_force_recovery = 4
+```
+
+    4) Redémarrer **mysqld**:
+
+  5a) Faire un dump des tables de la base avec **SELECT ... INTO OUTFILE**:
+
+```mysql
+MariaDB [zenphoto]> SELECT * FROM _tags INTO OUTFILE '/tmp/corrupted.txt';
+Query OK, 170 rows affected (0.011 sec)
+
+# Pour exporter au format csv:
+MariaDB [zenphoto]> SELECT * FROM _tags INTO OUTFILE '/tmp/corrupted.csv' FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TERMINATED BY '\r\n';
+Query OK, 170 rows affected (0.006 sec)
+
+```
+
+  5b) Faire. un dump de toutes les tables:
+
+```bash
+$ mysqldump -A -u root -ppassword > '/tmp/dump.sql';
+```
+
+    6) Parfois cela peut suffire. Sinon, 
+
+    7) Supprimer les tables / bases corrompues (DROP ...)
+
+    8) Arrêter **mysqld**:
+
+    9) Supprimer les ib*:
+
+```bash
+#Linux
+/var/lib/mysql/ib*
+
+#osx (Homebrew)
+/usr/local/var/mysql/ib*
+```
+
+    10) Quitter le mode force recovery:
+
+```
+[mysqld]
+#innodb_force_recovery = 0
+```
+
+    11) Redémarrer **mysqld**:
+
+    12) Restaurer les bases:
+
+```bash
+$ mysql -u root -ppassword < dump.sql
+```
+
+ 
+
+  https://www.nixpal.com/mysql-innodb-corruption-repair-guide/
+
+
+
+### Vérifier et réparer:
+
+Vérifier toutes les bases et réparer les tables corrompues:
+
+```bash
+$ mysqlcheck -u root -p -A --auto-repair
+
+Enter password:
+
+funnymac.download                                  OK
+funnymac.downloads                                 OK
+…/…
+```
+