Gitlab from sources : proper utf8mb4 support for MySQL 5.5 to 5.7

3 files changed, 208 insertions, 7 deletions

diff --git a/config/database.yml.mysql b/config/database.yml.mysql
index d9702870249..a33e40e8eb3 100644
--- a/config/database.yml.mysql
+++ b/config/database.yml.mysql
@@ -3,8 +3,8 @@
 #
 production:
   adapter: mysql2
-  encoding: utf8mb4
-  collation: utf8mb4_general_ci
+  encoding: utf8
+  collation: utf8_general_ci
   reconnect: false
   database: gitlabhq_production
   pool: 10
@@ -18,8 +18,8 @@ production:
 #
 development:
   adapter: mysql2
-  encoding: utf8mb4
-  collation: utf8mb4_general_ci
+  encoding: utf8
+  collation: utf8_general_ci
   reconnect: false
   database: gitlabhq_development
   pool: 5
diff --git a/doc/install/database_mysql.md b/doc/install/database_mysql.md
index 322680f0cf4..65bfb0f7d6e 100644
--- a/doc/install/database_mysql.md
+++ b/doc/install/database_mysql.md
@@ -4,7 +4,7 @@
 
 We do not recommend using MySQL due to various issues. For example, case [(in)sensitivity](https://dev.mysql.com/doc/refman/5.0/en/case-sensitivity.html) and [problems](https://bugs.mysql.com/bug.php?id=65830) that [suggested](https://bugs.mysql.com/bug.php?id=50909) [fixes](https://bugs.mysql.com/bug.php?id=65830) [have](https://bugs.mysql.com/bug.php?id=63164).
 
-## MySQL
+## Initial database setup
 
     # Install the database packages
     sudo apt-get install -y mysql-server mysql-client libmysqlclient-dev
@@ -32,8 +32,11 @@ We do not recommend using MySQL due to various issues. For example, case [(in)se
     # If this fails, check your MySQL config files (e.g. `/etc/mysql/*.cnf`, `/etc/mysql/conf.d/*`) for the setting "innodb = off"
     mysql> SET storage_engine=INNODB;
 
+    # If you have MySQL < 5.7.7 and want to enable utf8mb4 character set support with your GitLab install, you must set the following NOW:
+    mysql> SET GLOBAL innodb_file_per_table=1, innodb_file_format=Barracuda, innodb_large_prefix=1;
+
     # Create the GitLab production database
-    mysql> CREATE DATABASE IF NOT EXISTS `gitlabhq_production` DEFAULT CHARACTER SET `utf8` COLLATE `utf8_unicode_ci`;
+    mysql> CREATE DATABASE IF NOT EXISTS `gitlabhq_production` DEFAULT CHARACTER SET `utf8` COLLATE `utf8_general_ci`;
 
     # Grant the GitLab user necessary permissions on the database
     mysql> GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, CREATE TEMPORARY TABLES, DROP, INDEX, ALTER, LOCK TABLES, REFERENCES ON `gitlabhq_production`.* TO 'git'@'localhost';
@@ -51,7 +54,203 @@ We do not recommend using MySQL due to various issues. For example, case [(in)se
     # Quit the database session
     mysql> \q
 
-    # You are done installing the database and can go back to the rest of the installation.
+    # You are done installing the database for now and can go back to the rest of the installation.
+
+Please proceed to the rest of the installation before running through the utf8mb4 support section.
+
+
+### MySQL utf8mb4 support
+
+After installation or upgrade, remember to [convert any new tables](#convert) to `utf8mb4`/`utf8mb4_general_ci`.
+
+---
+
+GitLab 8.14 has introduced [a feature](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7420) requiring `utf8mb4` encoding to be supported in your GitLab MySQL Database, which is not the case if you have setup your database before GitLab 8.16.
+
+Follow the below instructions to ensure you use the most up to date requirements for your GitLab MySQL Database.
+
+**We are about to do the following:**
+- Ensure you can enable `utf8mb4` encoding and `utf8mb4_general_ci` collation for your GitLab DB, tables and data.
+- Convert your GitLab tables and data from `utf8`/`utf8_general_ci` to `utf8mb4`/`utf8mb4_general_ci`
+
+### Check for utf8mb4 support
+
+#### Check for InnoDB File-Per-Table Tablespaces
+
+We need to check, enable and maybe convert your existing GitLab DB tables to the [InnoDB File-Per-Table Tablespaces](http://dev.mysql.com/doc/refman/5.7/en/innodb-multiple-tablespaces.html) as a prerequise for supporting **utfb8mb4 with long indexes** required by recent GitLab databases.
+
+    # Login to MySQL
+    mysql -u root -p
+
+    # Type the MySQL root password
+    mysql > use gitlabhq_production;
+
+    # Check your MySQL version is >= 5.5.3 (GitLab requires 5.5.14+)
+    mysql > SHOW VARIABLES LIKE 'version';
+    +---------------+-----------------+
+    | Variable_name | Value           |
+    +---------------+-----------------+
+    | version       | 5.5.53-0+deb8u1 |
+    +---------------+-----------------+
+
+    # Note where is your MySQL data dir for later:
+    mysql > select @@datadir;
+    +----------------+
+    | @@datadir      |
+    +----------------+
+    | /var/lib/mysql |
+    +----------------+
+
+    # Note whether your MySQL server runs with innodb_file_per_table ON or OFF:
+    mysql> SELECT @@innodb_file_per_table;
+    +-------------------------+
+    | @@innodb_file_per_table |
+    +-------------------------+
+    |                       1 |
+    +-------------------------+
+
+    # You can now quit the database session
+    mysql> \q
+
+> You need **MySQL 5.5.3 or later** to perform this update.
+
+Whatever the results of your checks above, we now need to check if your GitLab database has been created using [InnoDB File-Per-Table Tablespaces](http://dev.mysql.com/doc/refman/5.7/en/innodb-multiple-tablespaces.html) (i.e. `innodb_file_per_table` was set to **1** at initial setup time).
+
+> Note: This setting is [enabled by default](http://dev.mysql.com/doc/refman/5.7/en/innodb-parameters.html#sysvar_innodb_file_per_table) since MySQL 5.6.6.
+
+    # Run this command with root privileges, replace the data dir if different:
+    sudo ls -lh /var/lib/mysql/gitlabhq_production/*.ibd | wc -l
+
+    # Run this command with root privileges, replace the data dir if different:
+    sudo ls -lh /var/lib/mysql/gitlabhq_production/*.frm | wc -l
+
+
+- **Case 1: a result > 0 for both commands**
+
+Congrats, your GitLab database uses the right InnoDB tablespace format.
+
+However, you must still ensure that any **future tables** created by GitLab will still use the right format:
+
+- If `SELECT @@innodb_file_per_table` returned **1** previously, your server is running correctly.
+> It's however a requirement to check *now* that this setting is indeed persisted in your [my.cnf](https://dev.mysql.com/doc/refman/5.7/en/tablespace-enabling.html) file!
+
+- If `SELECT @@innodb_file_per_table` returned **0** previously, your server is not running correctly.
+> [Enable innodb_file_per_table](https://dev.mysql.com/doc/refman/5.7/en/tablespace-enabling.html) by running in a MySQL session as root the command `SET GLOBAL innodb_file_per_table=1, innodb_file_format=Barracuda;` and persist the two settings in your [my.cnf](https://dev.mysql.com/doc/refman/5.7/en/tablespace-enabling.html) file
+
+Now, if you have a **different result** returned by the 2 commands above, it means you have a **mix of tables format** uses in your GitLab database. This can happen if your MySQL server had different values for `innodb_file_per_table` in its life and you updated GitLab at different moments with those inconsistent values. So keep reading.
+
+- **Case 2: a result equals to "0" OR not the same result for both commands**
+
+Unfortunately, none or only some of your GitLab database tables use the GitLab requirement of [InnoDB File-Per-Table Tablespaces](http://dev.mysql.com/doc/refman/5.7/en/innodb-multiple-tablespaces.html).
+
+Let's enable what we need on the running server:
+
+    # Login to MySQL
+    mysql -u root -p
+
+    # Type the MySQL root password
+
+    # Enable innodb_file_per_table and set innodb_file_format on the running server:
+    mysql > SET GLOBAL innodb_file_per_table=1, innodb_file_format=Barracuda;
+
+    # You can now quit the database session
+    mysql> \q
+
+> Now, **persist** [innodb_file_per_table](https://dev.mysql.com/doc/refman/5.6/en/tablespace-enabling.html) and [innodb_file_format](https://dev.mysql.com/doc/refman/5.6/en/innodb-file-format-enabling.html) in your `my.cnf` file.
+
+Ensure at this stage that your GitLab instance is indeed **stopped**.
+
+Now, let's convert all the GitLab database tables to the new tablespace format:
+
+    # Login to MySQL
+    mysql -u root -p
+
+    # Type the MySQL root password
+    mysql > use gitlabhq_production;
+
+    # Safety check: you should still have those values set as follow:
+    mysql> SELECT @@innodb_file_per_table, @@innodb_file_format;
+    +-------------------------+----------------------+
+    | @@innodb_file_per_table | @@innodb_file_format |
+    +-------------------------+----------------------+
+    |                       1 | Barracuda            |
+    +-------------------------+----------------------+
+
+    mysql > SELECT CONCAT('ALTER TABLE `', TABLE_NAME,'` ENGINE=InnoDB;') AS 'Copy & run these SQL statements:' FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA="gitlabhq_production" AND TABLE_TYPE="BASE TABLE";
+
+    # If previous query returned results, copy & run all shown SQL statements
+
+    # You can now quit the database session
+    mysql> \q
+
+---
+
+#### Check for proper InnoDB File Format, Row Format, Large Prefix and tables conversion
+
+We need to check, enable and probably convert your existing GitLab DB tables to use the [Barracuda InnoDB file format](https://dev.mysql.com/doc/refman/5.6/en/innodb-file-format.html), the [DYNAMIC row format](https://dev.mysql.com/doc/refman/5.6/en/glossary.html#glos_dynamic_row_format) and [innodb_large_prefix](http://dev.mysql.com/doc/refman/5.7/en/innodb-parameters.html#sysvar_innodb_large_prefix) as a second prerequisite for supporting **utfb8mb4 with long indexes** used by recent GitLab databases.
+
+    # Login to MySQL
+    mysql -u root -p
+
+    # Type the MySQL root password
+    mysql > use gitlabhq_production;
+
+    # Set innodb_file_format and innodb_large_prefix on the running server:
+    # Note: These are the default settings only for MySQL 5.7.7 and later.
+
+    mysql > SET GLOBAL innodb_file_format=Barracuda, innodb_large_prefix=1;
+
+    # Your DB must be (still) using utf8/utf8_general_ci as default encoding and collation.
+    # We will NOT change the default encoding and collation on the DB in order to support future GitLab migrations creating tables
+    # that require "long indexes support" on installations using MySQL <= 5.7.9.
+    # However, when such migrations occur, you will have to follow this guide again to convert the newly created tables to the proper encoding/collation.
+
+    # This should return the following:
+    mysql> SELECT @@character_set_database, @@collation_database;
+    +--------------------------+----------------------+
+    | @@character_set_database | @@collation_database |
+    +--------------------------+----------------------+
+    | utf8                     | utf8_general_ci      |
+    +--------------------------+----------------------+
+
+> Now, ensure that [innodb_file_format](https://dev.mysql.com/doc/refman/5.6/en/tablespace-enabling.html) and [innodb_large_prefix](http://dev.mysql.com/doc/refman/5.7/en/innodb-parameters.html#sysvar_innodb_large_prefix) are **persisted** in your `my.cnf` file.
+
+#### Tables and data conversion to utf8mb4
+<a name="convert"></a>
+
+Now that you have a persistent MySQL setup, you can safely upgrade tables after setup or upgrade time:
+
+    # Convert tables not using ROW_FORMAT DYNAMIC:
+
+    mysql> SELECT CONCAT('ALTER TABLE `', TABLE_NAME,'` ROW_FORMAT=DYNAMIC;') AS 'Copy & run these SQL statements:' FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA="gitlabhq_production" AND TABLE_TYPE="BASE TABLE" AND ROW_FORMAT!="Dynamic";
+
+    # !! If previous query returned results, copy & run all shown SQL statements
+
+    # Convert tables/columns not using utf8mb4/utf8mb4_general_ci as encoding/collation:
+
+    mysql > SET foreign_key_checks = 0;
+
+    mysql > SELECT CONCAT('ALTER TABLE `', TABLE_NAME,'` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;') AS 'Copy & run these SQL statements:' FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA="gitlabhq_production" AND TABLE_COLLATION != "utf8mb4_general_ci" AND TABLE_TYPE="BASE TABLE";
+
+    # !! If previous query returned results, copy & run all shown SQL statements
+
+    # Turn foreign key checks back on
+    mysql > SET foreign_key_checks = 1;
+
+    # You can now quit the database session
+    mysql> \q
+
+Ensure your GitLab database configuration file uses a proper connection encoding and collation:
+
+```sudo -u git -H editor config/database.yml```
+
+    production:
+      adapter: mysql2
+      encoding: utf8mb4
+      collation: utf8mb4_general_ci
+
+[Restart your GitLab instance](../administration/restart_gitlab.md).
+
 
 ## MySQL strings limits
 
diff --git a/doc/update/8.15-to-8.16.md b/doc/update/8.15-to-8.16.md
index 3d68fe201a7..d494db76912 100644
--- a/doc/update/8.15-to-8.16.md
+++ b/doc/update/8.15-to-8.16.md
@@ -97,6 +97,8 @@ sudo -u git -H bundle exec rake db:migrate RAILS_ENV=production
 sudo -u git -H bundle exec rake assets:clean assets:precompile cache:clear RAILS_ENV=production
 ```
 
+**MySQL installations**: Run through the `MySQL strings limits` and `Tables and data conversion to utf8mb4` [tasks](../install/database_mysql.md).
+
 ### 6. Update gitlab-workhorse
 
 Install and compile gitlab-workhorse. This requires