A recent incident at Retool highlighted the challenges and lessons of managing database migrations, particularly with PostgreSQL. The author recounts an unintended two-minute downtime caused by a mishandled database migration, emphasizing the importance of using transactions to maintain database integrity. The discussion extends to various migration strategies, such as safely deleting or renaming columns, conducting data backfills, and adding columns or indices, especially in high-traffic production environments. Specific techniques, such as batching operations and utilizing concurrent index builds, are recommended to prevent outages. The post underscores the significance of configuring the `statement_timeout` setting to mitigate potential issues swiftly, transforming potential prolonged outages into brief disruptions. The insights aim to guide engineers in navigating the complexities of database migrations, ensuring that their applications remain robust and reliable as they scale.