Update the docs to reflect lack of MySQL support52442-minimal-remove-mysql-support

Now MySQL is no longer supported, we need to change the docs

16 files changed, 21 insertions, 461 deletions

diff --git a/doc/administration/environment_variables.md b/doc/administration/environment_variables.md
index 864a84b33e0..874b1f3c80d 100644
--- a/doc/administration/environment_variables.md
+++ b/doc/administration/environment_variables.md
@@ -42,7 +42,7 @@ The list of `GITLAB_DATABASE_XXX` variables that you can set is:
 
 Variable | Default value | Overridden by `DATABASE_URL`?
 -------- | ------------- | -----------------------------
-`GITLAB_DATABASE_ADAPTER`   | `postgresql` (for MySQL use `mysql2`) | Yes
+`GITLAB_DATABASE_ADAPTER`   | `postgresql`                          | Yes
 `GITLAB_DATABASE_DATABASE`  | `gitlab_#{ENV['RAILS_ENV']`           | Yes
 `GITLAB_DATABASE_USERNAME`  | `root`                                | Yes
 `GITLAB_DATABASE_PASSWORD`  | None                                  | Yes
diff --git a/doc/administration/geo/replication/database.md b/doc/administration/geo/replication/database.md
index 1e5a56c3f4e..6658c37752a 100644
--- a/doc/administration/geo/replication/database.md
+++ b/doc/administration/geo/replication/database.md
@@ -489,10 +489,6 @@ work:
     gitlab-ctl reconfigure
     ```
 
-## MySQL replication
-
-MySQL replication is not supported for Geo.
-
 ## Troubleshooting
 
 Read the [troubleshooting document](troubleshooting.md).
diff --git a/doc/administration/index.md b/doc/administration/index.md
index 06d900b152d..602eecb9746 100644
--- a/doc/administration/index.md
+++ b/doc/administration/index.md
@@ -33,7 +33,6 @@ Learn how to install, configure, update, and maintain your GitLab instance.
 
 - [Install](../install/README.md): Requirements, directory structures, and installation methods.
   - [Database load balancing](database_load_balancing.md): Distribute database queries among multiple database servers. **[STARTER ONLY]**
-  - [Omnibus support for external MySQL DB](https://docs.gitlab.com/omnibus/settings/database.html#using-a-mysql-database-management-server-enterprise-edition-only): Omnibus package supports configuring an external MySQL database. **[STARTER ONLY]**
   - [Omnibus support for log forwarding](https://docs.gitlab.com/omnibus/settings/logs.html#udp-log-shipping-gitlab-enterprise-edition-only) **[STARTER ONLY]**
 - [High Availability](high_availability/README.md): Configure multiple servers for scaling or high availability.
   - [Installing GitLab HA on Amazon Web Services (AWS)](../install/aws/index.md): Set up GitLab High Availability on Amazon AWS.
diff --git a/doc/development/architecture.md b/doc/development/architecture.md
index d817d513173..a43a40152db 100644
--- a/doc/development/architecture.md
+++ b/doc/development/architecture.md
@@ -695,7 +695,7 @@ We've also detailed [our architecture of GitLab.com](https://about.gitlab.com/ha
 [runner-gdk]: https://gitlab.com/gitlab-org/gitlab-development-kit/blob/master/doc/howto/runner.md
 [database-migrations-omnibus]: https://docs.gitlab.com/omnibus/settings/database.html#disabling-automatic-database-migration
 [database-migrations-charts]: https://docs.gitlab.com/charts/charts/gitlab/migrations/
-[database-migrations-source]: ../update/upgrading_from_source.md#14-install-libs-migrations-etc
+[database-migrations-source]: ../update/upgrading_from_source.md#13-install-libs-migrations-etc
 [certificate-management-omnibus]: https://docs.gitlab.com/omnibus/settings/ssl.html
 [certificate-management-charts]: https://docs.gitlab.com/charts/installation/tls.html
 [certificate-management-source]: ../install/installation.md#using-https
diff --git a/doc/development/rake_tasks.md b/doc/development/rake_tasks.md
index 28a12572961..4fc10b6af5c 100644
--- a/doc/development/rake_tasks.md
+++ b/doc/development/rake_tasks.md
@@ -80,30 +80,6 @@ There are a few environment flags you can pass to change how projects are seeded
 - `LARGE_PROJECTS`: defaults to false. If set will clone 6 large projects to help with testing.
 - `FORK`: defaults to false. If set to `true` will fork `torvalds/linux` five times. Can also be set to an existing project full_path and it will fork that instead.
 
-### Notes for MySQL
-
-Since the seeds would contain various UTF-8 characters, such as emojis or so,
-we'll need to make sure that we're using `utf8mb4` for all the encoding
-settings and `utf8mb4_unicode_ci` for collation. Please check
-[MySQL utf8mb4 support](../install/database_mysql.md#mysql-utf8mb4-support)
-
-Make sure that `config/database.yml` has `encoding: utf8mb4`, too.
-
-Next, we'll need to update the schema to make the indices fit:
-
-``` shell
-sed -i 's/limit: 255/limit: 191/g' db/schema.rb
-```
-
-Then run the setup script:
-
-``` shell
-bundle exec rake setup
-```
-
-To make sure that indices still fit. You could find great details in:
-[How to support full Unicode in MySQL databases](https://mathiasbynens.be/notes/mysql-utf8mb4)
-
 ## Run tests
 
 In order to run the test you can use the following commands:
diff --git a/doc/development/swapping_tables.md b/doc/development/swapping_tables.md
index 29cd6a43aff..5c62900dbff 100644
--- a/doc/development/swapping_tables.md
+++ b/doc/development/swapping_tables.md
@@ -39,14 +39,6 @@ PostgreSQL you can use the `reset_pk_sequence!` method like so:
 reset_pk_sequence!('events')
 ```
 
-For MySQL however you need to do run the following:
-
-```ruby
-amount = Event.pluck('COALESCE(MAX(id), 1)').first
-
-execute "ALTER TABLE events AUTO_INCREMENT = #{amount}"
-```
-
 Failure to reset the primary keys will result in newly created rows starting
 with an ID value of 1. Depending on the existing data this can then lead to
 duplicate key constraints from popping up, preventing users from creating new
diff --git a/doc/install/database_mysql.md b/doc/install/database_mysql.md
deleted file mode 100644
index cbb3b766b4e..00000000000
--- a/doc/install/database_mysql.md
+++ /dev/null
@@ -1,319 +0,0 @@
----
-type: reference
----
-
-# Database MySQL
-
-NOTE: **Note:**
-We do not recommend using MySQL due to various issues.
-For example, there have been bugs with case
-[(in)sensitivity](https://dev.mysql.com/doc/refman/5.7/en/case-sensitivity.html).
-
-Bugs relating to case sensitivity:
-
-- <https://bugs.mysql.com/bug.php?id=65830>
-- <https://bugs.mysql.com/bug.php?id=50909>
-- <https://bugs.mysql.com/bug.php?id=65830>
-- <https://bugs.mysql.com/bug.php?id=63164>
-
-## Initial database setup
-
-```sh
-# Install the database packages
-sudo apt-get install -y mysql-server mysql-client libmysqlclient-dev
-
-# Ensure you have MySQL version 5.6 or later
-mysql --version
-
-# Pick a MySQL root password (can be anything), type it and press enter
-# Retype the MySQL root password and press enter
-
-# Secure your installation
-sudo mysql_secure_installation
-
-# Login to MySQL
-mysql -u root -p
-
-# Type the MySQL root password
-
-# Create a user for GitLab
-# do not type the 'mysql>', this is part of the prompt
-# change $password in the command below to a real password you pick
-mysql> CREATE USER 'git'@'localhost' IDENTIFIED BY '$password';
-
-# Ensure you can use the InnoDB engine which is necessary to support long indexes
-# 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;
-
-# If you use MySQL with replication, or just have MySQL configured with binary logging, you need to run the following to allow the use of `TRIGGER`:
-mysql> SET GLOBAL log_bin_trust_function_creators = 1;
-
-# Create the GitLab production database
-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, TRIGGER ON `gitlabhq_production`.* TO 'git'@'localhost';
-
-# Quit the database session
-mysql> \q
-
-# Try connecting to the new database with the new user
-sudo -u git -H mysql -u git -p -D gitlabhq_production
-
-# Type the password you replaced $password with earlier
-
-# You should now see a 'mysql>' prompt
-
-# Quit the database session
-mysql> \q
-```
-
-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 steps below.
-
-### `log_bin_trust_function_creators`
-
-If you use MySQL with replication, or just have MySQL configured with binary logging, all of your MySQL servers will need to have `log_bin_trust_function_creators` enabled to allow the use of `TRIGGER` in migrations. You have already set this global variable in the steps above, but to make it persistent, add the following to your `my.cnf` file:
-
-```
-log_bin_trust_function_creators=1
-```
-
-### MySQL utf8mb4 support
-
-After installation or upgrade, remember to [convert any new tables](#tables-and-data-conversion-to-utf8mb4) 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 set up 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](https://dev.mysql.com/doc/refman/5.7/en/innodb-multiple-tablespaces.html) as a prerequisite 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](https://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: **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**
-
-Congratulations, 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/innodb-multiple-tablespaces.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/innodb-multiple-tablespaces.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/innodb-multiple-tablespaces.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](https://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/5.7/en/innodb-multiple-tablespaces.html) and [innodb_file_format](https://dev.mysql.com/doc/refman/5.7/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 follows:
-    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/5.7/en/innodb-file-format.html), the [DYNAMIC row format](https://dev.mysql.com/doc/refman/5.7/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/5.7/en/innodb-multiple-tablespaces.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
-
-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
-
-After installation or upgrade, remember to run the `add_limits_mysql` Rake task:
-
-**Omnibus GitLab installations**
-
-```sh
-sudo gitlab-rake add_limits_mysql
-```
-
-**Installations from source**
-
-```sh
-bundle exec rake add_limits_mysql RAILS_ENV=production
-```
-
-The `text` type in MySQL has a different size limit than the `text` type in
-PostgreSQL. In MySQL `text` columns are limited to ~65kB, whereas in PostgreSQL
-`text` columns are limited up to ~1GB!
-
-The `add_limits_mysql` Rake task converts some important `text` columns in the
-GitLab database to `longtext` columns, which can persist values of up to 4GB
-(sometimes less if the value contains multibyte characters).
-
-Details can be found in the [PostgreSQL][postgres-text-type] and
-[MySQL](https://dev.mysql.com/doc/refman/5.7/en/string-type-overview.html) manuals.
-
-[postgres-text-type]: http://www.postgresql.org/docs/9.2/static/datatype-character.html
-[ce-38152]: https://gitlab.com/gitlab-org/gitlab-ce/issues/38152
-
-<!-- ## Troubleshooting
-
-Include any troubleshooting steps that you can foresee. If you know beforehand what issues
-one might have when setting this up, or when something is changed, or on upgrading, it's
-important to describe those, too. Think of things that may go wrong and include them here.
-This is important to minimize requests for support and to avoid doc comments with
-questions that you know someone might ask.
-
-Each scenario can be a third-level heading, e.g. `### Getting error message X`.
-If you have none to add when creating a doc, leave this section in place
-but commented out to help encourage others to add to it in the future. -->
diff --git a/doc/install/installation.md b/doc/install/installation.md
index e73bf2c16ff..4c1021d097f 100644
--- a/doc/install/installation.md
+++ b/doc/install/installation.md
@@ -293,10 +293,9 @@ sudo adduser --disabled-login --gecos 'GitLab' git
 
 ## 6. Database
 
-We recommend using a PostgreSQL database. For MySQL, see the [MySQL setup guide](database_mysql.md).
-
 NOTE: **Note:**
-Because we need to make use of extensions and concurrent index removal, you need at least PostgreSQL 9.2.
+Starting from GitLab 12.1, only PostgreSQL is supported. Because we need to make
+use of extensions and concurrent index removal, you need at least PostgreSQL 9.2.
 
 1. Install the database packages:
 
@@ -502,13 +501,8 @@ If you want to use HTTPS, see [Using HTTPS](#using-https) for the additional ste
 ### Configure GitLab DB Settings
 
 ```sh
-# PostgreSQL only:
 sudo -u git cp config/database.yml.postgresql config/database.yml
 
-# MySQL only:
-sudo -u git cp config/database.yml.mysql config/database.yml
-
-# PostgreSQL only:
 # Remove host, username, and password lines from config/database.yml.
 # Once modified, the `production` settings will be as follows:
 #
@@ -520,7 +514,7 @@ sudo -u git cp config/database.yml.mysql config/database.yml
 #
 sudo -u git -H editor config/database.yml
 
-# MySQL and remote PostgreSQL only:
+# Remote PostgreSQL only:
 # Update username/password in config/database.yml.
 # You only need to adapt the production settings (first part).
 # If you followed the database guide then please do as follows:
@@ -528,7 +522,6 @@ sudo -u git -H editor config/database.yml
 # You can keep the double quotes around the password
 sudo -u git -H editor config/database.yml
 
-# PostgreSQL and MySQL:
 # Make config/database.yml readable to git only
 sudo -u git -H chmod o-rwx config/database.yml
 ```
@@ -544,11 +537,7 @@ Make sure you have `bundle` (run `bundle -v`):
 - `< 2.x`.
 
 ```sh
-# For PostgreSQL (note, the option says "without ... mysql")
 sudo -u git -H bundle install --deployment --without development test mysql aws kerberos
-
-# Or if you use MySQL (note, the option says "without ... postgres")
-sudo -u git -H bundle install --deployment --without development test postgres aws kerberos
 ```
 
 NOTE: **Note:**
diff --git a/doc/install/requirements.md b/doc/install/requirements.md
index ee3d17704a2..92122fca7dd 100644
--- a/doc/install/requirements.md
+++ b/doc/install/requirements.md
@@ -104,32 +104,10 @@ installation (e.g. the number of users, projects, etc).
 
 We currently support the following databases:
 
-- PostgreSQL (highly recommended)
-- MySQL/MariaDB (strongly discouraged, not all GitLab features are supported, no support for [MySQL/MariaDB GTID](https://mariadb.com/kb/en/mariadb/gtid/))
-
-We highly recommend the use of PostgreSQL instead of MySQL/MariaDB as not all
-features of GitLab work with MySQL/MariaDB:
-
-1. MySQL support for subgroups was [dropped with GitLab 9.3][post].
-   See [issue #30472][30472] for more information.
-1. Geo does [not support MySQL](../administration/geo/replication/database.md). This means no supported Disaster Recovery solution if using MySQL. **[PREMIUM ONLY]**
-1. [Zero downtime migrations](../update/README.md#upgrading-without-downtime) do not work with MySQL.
-1. [Database load balancing](../administration/database_load_balancing.md) is
-   supported only for PostgreSQL. **[PREMIUM ONLY]**
-1. GitLab [optimizes the loading of dashboard events](https://gitlab.com/gitlab-org/gitlab-ce/issues/31806) using [PostgreSQL LATERAL JOINs](https://blog.heapanalytics.com/postgresqls-powerful-new-join-type-lateral/).
-1. In general, SQL optimized for PostgreSQL may run much slower in MySQL due to
-   differences in query planners. For example, subqueries that work well in PostgreSQL
-   may not be [performant in MySQL](https://dev.mysql.com/doc/refman/5.7/en/optimizing-subqueries.html).
-1. Binary column index length is limited to 20 bytes. This is accomplished with [a hack](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/config/initializers/mysql_set_length_for_binary_indexes.rb).
-1. MySQL requires a variety of hacks to increase limits on various columns, [for example](https://gitlab.com/gitlab-org/gitlab-ce/issues/49583).
-1. [The milestone filter runs slower queries on MySQL](https://gitlab.com/gitlab-org/gitlab-ce/issues/51173#note_99391731).
-1. We expect this list to grow over time.
-
-Existing users using GitLab with MySQL/MariaDB are advised to
-[migrate to PostgreSQL](../update/mysql_to_postgresql.md) instead.
-
-[30472]: https://gitlab.com/gitlab-org/gitlab-ce/issues/30472
-[post]: https://about.gitlab.com/2017/06/22/gitlab-9-3-released/#dropping-support-for-subgroups-in-mysql
+- PostgreSQL
+
+Support for MySQL was removed in GitLab 12.1. Existing users using GitLab with
+MySQL/MariaDB are advised to [migrate to PostgreSQL](../update/mysql_to_postgresql.md) before upgrading.
 
 ### PostgreSQL Requirements
 
diff --git a/doc/integration/omniauth.md b/doc/integration/omniauth.md
index a13e9f73f48..bf5debc7694 100644
--- a/doc/integration/omniauth.md
+++ b/doc/integration/omniauth.md
@@ -194,11 +194,7 @@ from the Omniauth provider's documentation.
 
         gem "omniauth-your-auth-provider"
 
--   If you're using MySQL, install the new Omniauth provider gem by running the following command:
-
-        sudo -u git -H bundle install --without development test postgres --path vendor/bundle --no-deployment
-
--   If you're using PostgreSQL, install the new Omniauth provider gem by running the following command:
+-   Install the new Omniauth provider gem by running the following command:
 
         sudo -u git -H bundle install --without development test mysql --path vendor/bundle --no-deployment
 
diff --git a/doc/university/README.md b/doc/university/README.md
index c116e54ad48..1d2c0f2068a 100644
--- a/doc/university/README.md
+++ b/doc/university/README.md
@@ -149,7 +149,6 @@ The GitLab University curriculum is composed of GitLab videos, screencasts, pres
 1. [How to Install GitLab with Omnibus - Video](https://www.youtube.com/watch?v=Q69YaOjqNhg)
 1. [Installing GitLab - Online Course](https://courses.platzi.com/classes/git-gitlab/concepto/part-1/part-3/material/)
 1. [Using a Non-Packaged PostgreSQL Database](https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/README.md#using-a-non-packaged-postgresql-database-management-server)
-1. [Using a MySQL Database](https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/README.md#using-a-mysql-database-management-server-enterprise-edition-only)
 1. [Installing GitLab on Microsoft Azure](https://about.gitlab.com/2016/07/13/how-to-setup-a-gitlab-instance-on-microsoft-azure/)
 1. [Installing GitLab on Digital Ocean](https://about.gitlab.com/2016/04/27/getting-started-with-gitlab-and-digitalocean/)
 
diff --git a/doc/update/README.md b/doc/update/README.md
index 58227b6fd3f..974982da5d0 100644
--- a/doc/update/README.md
+++ b/doc/update/README.md
@@ -49,8 +49,7 @@ However, for this to work there are the following requirements:
 - You have to use [post-deployment
    migrations](../development/post_deployment_migrations.md) (included in
    zero downtime update steps below).
-- You are using PostgreSQL. If you are using MySQL please look at the release
-   post to see if downtime is required.
+- You are using PostgreSQL. Starting from GitLab 12.1, MySQL is not supported.
 
 Most of the time you can safely upgrade from a patch release to the next minor
 release if the patch release is not the latest. For example, upgrading from
@@ -140,8 +139,6 @@ possible.
 
 - [MySQL to PostgreSQL](mysql_to_postgresql.md) guides you through migrating
   your database from MySQL to PostgreSQL.
-- [MySQL installation guide](../install/database_mysql.md) contains additional
-  information about configuring GitLab to work with a MySQL database.
 - [Restoring from backup after a failed upgrade](restore_after_failure.md)
 - [Upgrading PostgreSQL Using Slony](upgrading_postgresql_using_slony.md), for
   upgrading a PostgreSQL database with minimal downtime.
diff --git a/doc/update/mysql_to_postgresql.md b/doc/update/mysql_to_postgresql.md
index b83abcd36f7..4b13e41ab53 100644
--- a/doc/update/mysql_to_postgresql.md
+++ b/doc/update/mysql_to_postgresql.md
@@ -1,5 +1,5 @@
 ---
-last_updated: 2019-03-27
+last_updated: 2019-06-18
 ---
 
 # Migrating from MySQL to PostgreSQL
@@ -9,6 +9,10 @@ migrate it to a PostgreSQL database.
 
 ## Requirements
 
+NOTE: **Note:**
+Support for MySQL was removed in GitLab 12.1. This procedure should be performed
+**before** installing GitLab 12.1.
+
 [pgloader](http://pgloader.io) 3.4.1+ is required.
 
 You can install it directly from your distribution, for example in
diff --git a/doc/update/patch_versions.md b/doc/update/patch_versions.md
index f2df4277ca8..4300d6d56c7 100644
--- a/doc/update/patch_versions.md
+++ b/doc/update/patch_versions.md
@@ -13,8 +13,6 @@ You can select the tag in the version dropdown in the top left corner of GitLab
 ### 0. Backup
 
 It's useful to make a backup just in case things go south:
-(With MySQL, this may require granting "LOCK TABLES" privileges to the GitLab
-user on the database version)
 
 ```bash
 cd /home/git/gitlab
@@ -48,12 +46,8 @@ sudo -u git -H git checkout LATEST_TAG -b LATEST_TAG
 ```bash
 cd /home/git/gitlab
 
-# PostgreSQL
 sudo -u git -H bundle install --without development test mysql --deployment
 
-# MySQL
-sudo -u git -H bundle install --without development test postgres --deployment
-
 # Optional: clean up old gems
 sudo -u git -H bundle clean
 
diff --git a/doc/update/upgrading_from_source.md b/doc/update/upgrading_from_source.md
index a05af7350de..023dc7d6de3 100644
--- a/doc/update/upgrading_from_source.md
+++ b/doc/update/upgrading_from_source.md
@@ -239,29 +239,7 @@ sudo -u git -H git checkout v$(</home/git/gitlab/GITLAB_PAGES_VERSION)
 sudo -u git -H make
 ```
 
-### 12. Update MySQL permissions
-
-If you are using MySQL you need to grant the GitLab user the necessary
-permissions on the database:
-
-```bash
-mysql -u root -p -e "GRANT TRIGGER ON \`gitlabhq_production\`.* TO 'git'@'localhost';"
-```
-
-If you use MySQL with replication, or just have MySQL configured with binary logging,
-you will need to also run the following on all of your MySQL servers:
-
-```bash
-mysql -u root -p -e "SET GLOBAL log_bin_trust_function_creators = 1;"
-```
-
-You can make this setting permanent by adding it to your `my.cnf`:
-
-```
-log_bin_trust_function_creators=1
-```
-
-### 13. Update configuration files
+### 12. Update configuration files
 
 #### New configuration options for `gitlab.yml`
 
@@ -335,18 +313,13 @@ For Ubuntu 16.04.1 LTS:
 sudo systemctl daemon-reload
 ```
 
-### 14. Install libs, migrations, etc.
+### 13. Install libs, migrations, etc.
 
 ```bash
 cd /home/git/gitlab
 
-# PostgreSQL installations (note: the line below states '--without mysql')
 sudo -u git -H bundle install --deployment --without development test mysql aws kerberos
 
-# MySQL installations (note: the line below states '--without postgres')
-sudo -u git -H bundle install --deployment --without development test postgres aws kerberos
-
-
 # Optional: clean up old gems
 sudo -u git -H bundle clean
 
@@ -364,17 +337,14 @@ sudo -u git -H bundle exec rake yarn:install gitlab:assets:clean gitlab:assets:c
 sudo -u git -H bundle exec rake 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).
-
-### 15. Start application
+### 14. Start application
 
 ```bash
 sudo service gitlab start
 sudo service nginx restart
 ```
 
-### 16. Check application status
+### 15. Check application status
 
 Check if GitLab and its environment are configured correctly:
 
diff --git a/doc/user/group/subgroups/index.md b/doc/user/group/subgroups/index.md
index 79ae94dd9ef..1c6cca049c5 100644
--- a/doc/user/group/subgroups/index.md
+++ b/doc/user/group/subgroups/index.md
@@ -5,8 +5,7 @@ type: reference, howto, concepts
 # Subgroups
 
 NOTE: **Note:**
-[Introduced](https://gitlab.com/gitlab-org/gitlab-ce/issues/2772) in GitLab 9.0. Not available when using MySQL as external
-database (support removed in GitLab 9.3 [due to performance reasons](https://gitlab.com/gitlab-org/gitlab-ce/issues/30472#note_27747600)).
+[Introduced](https://gitlab.com/gitlab-org/gitlab-ce/issues/2772) in GitLab 9.0.
 
 Subgroups, also known as nested groups or hierarchical groups, allow you to have up to 20
 levels of groups.
@@ -21,16 +20,6 @@ By using subgroups you can do the following:
 - **Make it easier to manage people and control visibility.** Give people
   different [permissions](../../permissions.md#group-members-permissions) depending on their group [membership](#membership).
 
-## Database Requirements
-
-Subgroups are only supported when you use PostgreSQL. Supporting subgroups on MySQL in an
-efficient way is not possible due to MySQL's limitations.
-
-See the following links for more information:
-
-- <https://gitlab.com/gitlab-org/gitlab-ce/issues/30472>
-- <https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10885>
-
 ## Overview
 
 A group can have many subgroups inside it, and at the same time a group can have