postgresql

Complex reporting queries with multiple joins and aggregations can become unmaintainable in ActiveRecord. PostgreSQL views encapsulate query complexity in the database layer and appear as regular tables to Rails. I create views for common reporting ne

SaaS applications serving multiple customers (tenants) need data isolation to prevent cross-tenant data leaks. The apartment gem provides schema-based multi-tenancy for PostgreSQL where each tenant gets a separate schema, ensuring complete database-le

Proper indexing is the difference between millisecond and multi-second query response times. I add indexes to foreign keys automatically since Rails doesn't do this by default, and I create composite indexes for common query patterns that filter on mu

While ActiveRecord validations catch most invalid data, database constraints provide a safety net that prevents invariant violations even when validations are bypassed. I add null: false constraints for required columns, unique indexes for uniqueness

As applications grow, read operations often dominate database load. Directing reads to replica databases while keeping writes on the primary reduces contention and improves response times. Rails makes this straightforward with connects_to and role-bas

Understanding query execution plans is essential for optimizing slow queries. Rails provides explain method on ActiveRecord relations to show PostgreSQL's query planner output. I look for sequential scans on large tables (indicating missing indexes),

PostgreSQL's jsonb columns provide schema flexibility for semi-structured data without sacrificing query performance. I use JSON columns for user preferences, feature flags, or metadata that varies by record type. Unlike traditional EAV patterns, json