postgres-best-practices

To add an index in PostgreSQL without locking the table, use the CONCURRENTLY keyword during migration. This allows concurrent inserts, updates, and deletes while the index builds, ensuring zero-downtime schema changes.

The best way to design PostgreSQL schema constraints for data integrity is to explicitly define NOT NULL, UNIQUE, and FOREIGN KEY constraints. This enforces data validity at the database level and prevents anomalous records.

Tune slow PostgreSQL queries by running EXPLAIN (ANALYZE, BUFFERS) to inspect execution plans. This reveals sequential scans, high cost operations, and buffer usage, guiding indexing strategy and query rewrites.

You need partial indexes in PostgreSQL when queries frequently filter on a specific subset of rows. By indexing only rows matching a WHERE clause, you reduce index size and improve query performance for targeted patterns.

Plan zero-downtime migrations for large PostgreSQL tables by using phased backfills and staged rollouts. This approach separates schema changes from data updates, avoiding long-held locks and maintaining application availability.

PostgreSQL migrations cause performance regressions when adding indexes without CONCURRENTLY or altering columns with heavy locks. Lock-aware DDL operations and verifying execution plans prevent these blocking incidents.