Jack Lindamood: devops decisions I regret

(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at: lawrence@krubner.com, or follow me on Twitter.

A great list of advice. This part, about stuffing everything into one great big database, might be the most interesting part:

Multiple applications sharing a database 

🟥 Regret

Like most tech debt, we didn’t make this decision, we just did not not make this decision. Eventually, someone wants the product to do a new thing and makes a new table. This feels good because there are now foreign keys between the two tables. But since everything is owned by someone and that someone is a row in a table, you’ve got foreign keys between all objects in the entire stack.

Since the database is used by everyone, it becomes cared for by no one. Startups don’t have the luxury of a DBA, and everything owned by no one is owned by infrastructure eventually.

The biggest problem with a shared database are:

  • Crud accumulates in the database, and it’s unclear if it can be deleted.
  • When there are performance issues, infrastructure (without deep product knowledge) has to debug the database and figure out who to redirect to
  • Database users can push bad code that does bad things to the database. These bad things may PagerDuty alert the infrastructure team (since they own the database). It feels bad to wake up one team for another team’s issue. With application owned databases, the application team is the first responder.

All that said, I’m not against stacks that want to share a single database either. Just be aware of the tradeoffs above and have a good story for how you’ll manage them.

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