debian-mirror-gitlab/doc/development/database_debugging.md
2018-03-27 19:54:05 +05:30

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# Database Debugging and Troubleshooting
This section is to help give some copy-pasta you can use as a reference when you
run into some head-banging database problems.
An easy first step is to search for your error in Slack or google "GitLab <my error>".
---
Available `RAILS_ENV`
- `production` (generally not for your main GDK db, but you may need this for e.g. omnibus)
- `development` (this is your main GDK db)
- `test` (used for tests like rspec and spinach)
## Nuke everything and start over
If you just want to delete everything and start over with an empty DB (~1 minute):
- `bundle exec rake db:reset RAILS_ENV=development`
If you just want to delete everything and start over with dummy data (~40 minutes). This also does `db:reset` and runs DB-specific migrations:
- `bundle exec rake dev:setup RAILS_ENV=development`
If your test DB is giving you problems, it is safe to nuke it because it doesn't contain important data:
- `bundle exec rake db:reset RAILS_ENV=test`
## Migration wrangling
- `bundle exec rake db:migrate RAILS_ENV=development`: Execute any pending migrations that you may have picked up from a MR
- `bundle exec rake db:migrate:status RAILS_ENV=development`: Check if all migrations are `up` or `down`
- `bundle exec rake db:migrate:down VERSION=20170926203418 RAILS_ENV=development`: Tear down a migration
- `bundle exec rake db:migrate:up VERSION=20170926203418 RAILS_ENV=development`: Setup a migration
- `bundle exec rake db:migrate:redo VERSION=20170926203418 RAILS_ENV=development`: Re-run a specific migration
## Manually access the database
Access the database via one of these commands (they all get you to the same place)
```
gdk psql -d gitlabhq_development
bundle exec rails dbconsole RAILS_ENV=development
bundle exec rails db RAILS_ENV=development
```
- `\q`: Quit/exit
- `\dt`: List all tables
- `\d+ issues`: List columns for `issues` table
- `CREATE TABLE board_labels();`: Create a table called `board_labels`
- `SELECT * FROM schema_migrations WHERE version = '20170926203418';`: Check if a migration was run
- `DELETE FROM schema_migrations WHERE version = '20170926203418';`: Manually remove a migration
## FAQ
### `ActiveRecord::PendingMigrationError` with Spring
When running specs with the [Spring preloader](./rake_tasks.md#speed-up-tests-rake-tasks-and-migrations),
the test database can get into a corrupted state. Trying to run the migration or
dropping/resetting the test database has no effect.
```sh
$ bundle exec spring rspec some_spec.rb
...
Failure/Error: ActiveRecord::Migration.maintain_test_schema!
ActiveRecord::PendingMigrationError:
Migrations are pending. To resolve this issue, run:
bin/rake db:migrate RAILS_ENV=test
# ~/.rvm/gems/ruby-2.3.3/gems/activerecord-4.2.10/lib/active_record/migration.rb:392:in `check_pending!'
...
0 examples, 0 failures, 1 error occurred outside of examples
```
To resolve, you can kill the spring server and app that lives between spec runs.
```sh
$ ps aux | grep spring
eric 87304 1.3 2.9 3080836 482596 ?? Ss 10:12AM 4:08.36 spring app | gitlab | started 6 hours ago | test mode
eric 37709 0.0 0.0 2518640 7524 s006 S Wed11AM 0:00.79 spring server | gitlab | started 29 hours ago
$ kill 87304
$ kill 37709
```