utf8mb4

tasks/mysql.yml

@@ -11,5 +11,7 @@
 - name: mysql database
   mysql_db:
     name: "{{nextcloud_database_name}}"
+    encoding: utf8mb4
+    collation: utf8mb4_unicode_ci
     state: present
   delegate_to: "{{ nextcloud_database_host }}"

templates/config.php.j2

@@ -108,6 +108,38 @@ $CONFIG = array(
  */
 'installed' => false,
 
+/**
+ * During setup, if requirements are met (see below), this setting is set to true
+ * and MySQL can handle 4 byte characters instead of 3 byte characters.
+ *
+ * If you want to convert an existing 3-byte setup into a 4-byte setup please
+ * set the parameters in MySQL as mentioned below and run the migration command:
+ * ./occ db:convert-mysql-charset
+ * The config setting will be set automatically after a successful run.
+ *
+ * Consult the documentation for more details.
+ *
+ * MySQL requires a special setup for longer indexes (> 767 bytes) which are
+ * needed:
+ *
+ * [mysqld]
+ * innodb_large_prefix=ON
+ * innodb_file_format=Barracuda
+ * innodb_file_per_table=ON
+ *
+ * Tables will be created with
+ *  * character set: utf8mb4
+ *  * collation:     utf8mb4_bin
+ *  * row_format:    compressed
+ *
+ * See:
+ * https://dev.mysql.com/doc/refman/5.7/en/charset-unicode-utf8mb4.html
+ * https://dev.mysql.com/doc/refman/5.7/en/innodb-parameters.html#sysvar_innodb_large_prefix
+ * https://mariadb.com/kb/en/mariadb/xtradbinnodb-server-system-variables/#innodb_large_prefix
+ * http://www.tocker.ca/2013/10/31/benchmarking-innodb-page-compression-performance.html
+ * http://mechanics.flite.com/blog/2014/07/29/using-innodb-large-prefix-to-avoid-error-1071/
+ */
+'mysql.utf8mb4' => true,
 
 /**
  * User Experience