3 Best Practices For Zero-Downtime Database Migrations

The text describes a process for migrating databases with zero downtime, drawing an analogy to Indiana Jones' iconic scene in Raiders of the Lost Ark. It outlines three best practices developed by LaunchDarkly during their migration from MongoDB and PostgreSQL to CockroachDB: leveraging production traffic, making migrations gradual and instantly reversible without deploying code changes, and splitting migrations into cohorts. These practices involve using feature flags to control read and write operations between old and new databases, gradually shifting traffic through a 6-stage process, and dividing traffic into different cohorts for testing and optimizing the migration.