Commit 7c5fe037 authored by Lin Jen-Shin (godfat)'s avatar Lin Jen-Shin (godfat) Committed by Achilleas Pipinellis

Document how to use pgloader

parent 6c5837ae
*** NOTE: These instructions should be considered deprecated. In GitLab 10.0 we will be releasing new migration instructions using [pgloader](http://pgloader.io/). ---
last_updated: 2017-10-05
---
# Migrating GitLab from MySQL to Postgres # Migrating from MySQL to PostgreSQL
*Make sure you view this [guide from the `master` branch](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/update/mysql_to_postgresql.md#migrating-gitlab-from-mysql-to-postgres) for the most up to date instructions.*
If you are replacing MySQL with Postgres while keeping GitLab on the same server all you need to do is to export from MySQL, convert the resulting SQL file, and import it into Postgres. If you are also moving GitLab to another server, or if you are switching to omnibus-gitlab, you may want to use a GitLab backup file. The second part of this documents explains the procedure to do this. > **Note:** This guide assumes you have a working Omnibus GitLab instance with
> MySQL and want to migrate to bundled PostgreSQL database.
## Export from MySQL and import into Postgres ## Prerequisites
Use this if you are keeping GitLab on the same server. First, we'll need to enable the bundled PostgreSQL database with up-to-date
schema. Next, we'll use [pgloader](http://pgloader.io) to migrate the data
from the old MySQL database to the new PostgreSQL one.
``` Here's what you'll need to have installed:
sudo service gitlab stop
# Update /home/git/gitlab/config/database.yml - pgloader 3.4.1+
- Omnibus GitLab
- MySQL
git clone https://github.com/gitlabhq/mysql-postgresql-converter.git -b gitlab ## Enable bundled PostgreSQL database
cd mysql-postgresql-converter
mysqldump --compatible=postgresql --default-character-set=utf8 -r gitlabhq_production.mysql -u root gitlabhq_production -p
python db_converter.py gitlabhq_production.mysql gitlabhq_production.psql
ed -s gitlabhq_production.psql < move_drop_indexes.ed
# Import the database dump as the application database user 1. Stop GitLab:
sudo -u git psql -f gitlabhq_production.psql -d gitlabhq_production
# Install gems for PostgreSQL (note: the line below states '--without ... mysql') ``` bash
sudo -u git -H bundle install --without development test mysql --deployment sudo gitlab-ctl stop
```
sudo service gitlab start 1. Edit `/etc/gitlab/gitlab.rb` to enable bundled PostgreSQL:
```
## Converting a GitLab backup file from MySQL to Postgres ```
**Note:** Please make sure to have Python 2.7.x (or higher) installed. postgresql['enable'] = true
```
GitLab backup files (`<timestamp>_gitlab_backup.tar`) contain a SQL dump. Using the lanyrd database converter we can replace a MySQL database dump inside the tar file with a Postgres database dump. This can be useful if you are moving to another server. 1. Edit `/etc/gitlab/gitlab.rb` to use the bundled PostgreSQL. Please check
all the settings beginning with `db_`, such as `gitlab_rails['db_adapter']`
and alike. You could just comment all of them out so that we'll just use
the defaults.
``` 1. [Reconfigure GitLab] for the changes to take effect:
# Stop GitLab
sudo service gitlab stop ``` bash
sudo gitlab-ctl reconfigure
```
1. Start Unicorn and PostgreSQL so that we could prepare the schema:
``` bash
sudo gitlab-ctl start unicorn
sudo gitlab-ctl start posgresql
```
1. Run the following commands to prepare the schema:
``` bash
sudo gitlab-rake db:create db:migrate
```
1. Stop Unicorn in case it's interfering the next step:
# Create the backup ``` bash
cd /home/git/gitlab sudo gitlab-ctl stop unicorn
sudo -u git -H bundle exec rake gitlab:backup:create RAILS_ENV=production ```
# Note the filename of the backup that was created. We will call it After these steps, you'll have a fresh PostgreSQL database with up-to-date schema.
# TIMESTAMP_gitlab_backup.tar below.
# Move the backup file we will convert to its own directory ## Migrate data from MySQL to PostgreSQL
sudo -u git -H mkdir -p tmp/backups/postgresql
sudo -u git -H mv tmp/backups/TIMESTAMP_gitlab_backup.tar tmp/backups/postgresql/
# Create a separate database dump with PostgreSQL compatibility Now, you can use pgloader to migrate the data from MySQL to PostgreSQL:
cd tmp/backups/postgresql
sudo -u git -H mysqldump --compatible=postgresql --default-character-set=utf8 -r gitlabhq_production.mysql -u root gitlabhq_production -p
# Clone the database converter 1. Save the following snippet in a `commands.load` file, and edit with your
sudo -u git -H git clone https://github.com/gitlabhq/mysql-postgresql-converter.git -b gitlab database `username`, `password` and `host`:
# Convert gitlabhq_production.mysql ```
sudo -u git -H mkdir db LOAD DATABASE
sudo -u git -H python mysql-postgresql-converter/db_converter.py gitlabhq_production.mysql db/database.sql FROM mysql://username:password@host/gitlabhq_production
sudo -u git -H ed -s db/database.sql < mysql-postgresql-converter/move_drop_indexes.ed INTO postgresql://gitlab-psql@unix://var/opt/gitlab/postgresql:/gitlabhq_production
# Compress database backup WITH include no drop, truncate, disable triggers, create no tables,
# Warning: If you have Gitlab 7.12.0 or older skip this step and import the database.sql directly into the backup with: create no indexes, preserve index names, no foreign keys,
# sudo -u git -H tar rf TIMESTAMP_gitlab_backup.tar db/database.sql data only
# The compressed databasedump is not supported at 7.12.0 and older.
sudo -u git -H gzip db/database.sql
# Replace the MySQL dump in TIMESTAMP_gitlab_backup.tar. ALTER SCHEMA 'gitlabhq_production' RENAME TO 'public'
# Warning: if you forget to replace TIMESTAMP below, tar will create a new file ;
# 'TIMESTAMP_gitlab_backup.tar' without giving an error. ```
sudo -u git -H tar rf TIMESTAMP_gitlab_backup.tar db/database.sql.gz 1. Start the migration:
# Done! TIMESTAMP_gitlab_backup.tar can now be restored into a Postgres GitLab ``` bash
# installation. sudo -u gitlab-psql pgloader commands.load
# See https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/raketasks/backup_restore.md for more information about backups. ```
1. Once the migration finishes, start GitLab:
``` bash
sudo gitlab-ctl start
```
Now, you can verify that everything worked by visiting GitLab.
## Troubleshooting
### Experiencing 500 errors after the migration
If you experience 500 errors after the migration, try to clear the cache:
``` bash
sudo gitlab-rake cache:clear
``` ```
[reconfigure GitLab]: ../administration/restart_gitlab.md#omnibus-gitlab-reconfigure
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