# shift <img src="/ui/public/logo.png" height="40">
shift is an application that makes it easy to run online schema migrations for MySQL databases

> [!NOTE]
> **Shift is no longer under active development.** Its successor is [SchemaBot](https://github.com/block/schemabot), Block's GitOps tool for database schema changes: describe the desired schema in SQL files, open a pull request, and SchemaBot plans, applies, and verifies the change. Online MySQL schema changes run with [Spirit](https://github.com/block/spirit).

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<img src="/ui/screenshots/summary.png">
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## Who should use it?
shift was designed to solve the following problem - running schema migrations manually takes too much time. As such, it is most effective when schema migrations are taking up too much of your time (ex: for an operations or DBA team at a large organization), but really it can be used by anyone. As of writing this, shift has had no problem running hundreds of migrations a day or running migrations that take over a week to complete.

## Features
* safe, online schema changes (invokes the tried-and-true pt-online-schema-change)
    * supports all "ALTER TABLE...", "CREATE TABLE...", or "DROP TABLE..." ddl
* a ui where you can see the status of migrations and run them with the click of a button
* self-service - out of the box, any user can file and run migrations, and an admin is only required to approve the ddl (this is all configurable though)
* shard support - easily run a single migration on any number of shards

## Components
shift consists of 3 components. Each component has its own readme with more details
* [ui](https://github.com/square/shift/tree/master/ui): a rails app where you can file, track, and run database migrations
* [runner](https://github.com/square/shift/tree/master/runner): a go agent that consumes jobs from an api exposed by the ui
* [pt-osc patch](https://github.com/square/shift/tree/master/ptosc-patch): a patch for pt-online-schema-change from the percona toolkit

## Demo
Watch a demo video [here](https://www.youtube.com/watch?v=u5L7PqIk--k)

## Installation
Read the installation guide [here](https://github.com/square/shift/wiki/Installation-Guide)

## License

Copyright (c) 2016 Square Inc. Distributed under the Apache 2.0 License.
See LICENSE file for further details.