# How to restore the database

### Introduction
It may be necessary on occasion to restore the database, for example if the database has become corrupted or following an incident. This document outlines the steps needed to perform a databse restore.

### Prerequisites
* Postgres database installed on target machine
* Access to pg_restore tool
* Access to command line tool
* Python 3.x installed
* Copy of Monitor my satellites Python backend from Github (needed for alembic command and for restoring the database schema)
* Installed all the Python requirements.txt tools (needed for alembic command)
* Optional: virtual environment created and set via source venv/bin/activate

The database is archived using the `Postgres pg_dump` tool. It is archived into a directory in compressed format.

<%= warning_text('Database was archived with only data (`--data-only` switch in `pg_dump`), not the database schema. It is important to know that limitation.') %>

### Restore process
To restore the database into a new location, the following steps need to be completed:
* `run psql` in command prompt
* setup a clean database “postgres” with command `CREATE DATABASE postgres;` in psql
* run alembic upgrade head from the main application folder. This will create the database structure

<%= warning_text('main application folder is the main folder of the cloned Github repository where subfolder `migrations/` resides') %>
* `run pg_restore -d postgres -p 5444 -F d path_to_folder_with_db_backup`. The port number may be different in your case.

The whole process can take up to a few hours to finish, depending on the amount of data in the archived database.