Zero-Downtime Database Migrations in Laravel

Short summary

Zero-downtime database migrations use the Expand and Contract Pattern—a three-phase approach that adds new columns, backfills data, then removes old ones. This strategy ensures application code and database schema never conflict during deployment. Teams can safely execute major migrations during peak traffic without downtime.

• •Expand: Add new columns without removing old ones, update code to write to both simultaneously
• •Migrate: Backfill historical data in the background using queues without locking tables
• •Contract: Drop old columns after confirming new logic works across the entire system

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