Some of them are sharded, so we have to ask: Where do the affected tables exist in our clusters or schemas? Next, we need to know what to run. Taking the change to productionĪt this point, we need to determine where the change is taking place since we have multiple clusters. Assuming all reviews are favorable, it’s on the database infrastructure engineer to deploy the change to production. The database infrastructure team reviews the changes, looking for performance concerns, among other potential issues. Then, they seek the agreement of the database infrastructure team, who owns the production databases. Depending on the change, they may ask for a review from a group of schema reviewers (at GitHub, this is a volunteer group experienced with database design). First, they seek review and discussion with their peers. The developer doesn’t just apply their changes online. The developer has a local testing environment where they can experiment however they like, until they’re satisfied and wish to apply changes to production. Maybe they need a new table, or a new column in an existing table. It begins with a developer who identifies the need for a schema change. Here’s the flow as we experience it at GitHub: 1. At a closer look, the process is far more complex, and involves multiple owners, platforms, environments, and transitions between those pieces. What’s in a migration?Īt first glance, migrating appears to be no more difficult than adding a CREATE, ALTER or DROP TABLE statement.
#Dbschema review manual#
We’ll cover how this amounted to a significant toil on the database infrastructure team, and how we searched for a solution to automate the manual parts of the process. Some days we have a half dozen migrations to run.
![dbschema review dbschema review](https://images.g2crowd.com/uploads/attachment/file/136219/sync-dialog.png)
On average, we have two schema migrations running daily on our production servers.
![dbschema review dbschema review](https://static.macupdate.com/screenshots/287639/m/dbschema-screenshot.png)
New features may require new tables, columns, changes to existing columns or indexes, dropping unused tables, and so on.
#Dbschema review code#
With MySQL serving our backends, updating code requires changes to the underlying database schema. Needless to say, the development pace at GitHub is accelerated.
![dbschema review dbschema review](https://files10.com/wp-content/uploads/2019/04/DbSchema-Screenshot-1-530x250.png)
In the past year, GitHub engineers shipped GitHub Packages, Actions, Sponsors, Mobile, security advisories and updates, notifications, code navigation, and more.