PostgreSQL

2 articles

Database 02 Sep 2026 5 min read

Covering Indexes and Index-Only Scans for Faster Database Reads

An index normally helps a database find rows. A covering index can go further: it contains all columns needed by a query, allowing the database engine to answer some reads without fetching every matching row from the table. That can reduce random I/O for read-heavy workloads, but it also makes indexes larger and writes more expensive. Covering is a workload-specific optimization, not a reason to copy every selected column into every index.

Database PostgreSQL

Database 01 Sep 2026 3 min read

Enforce Non-Overlapping Time Ranges with PostgreSQL Exclusion Constraints

Applications that schedule rooms, equipment, or maintenance windows often need a simple invariant: two active reservations for the same resource must not overlap. Checking for conflicts in application code looks easy, but concurrent transactions can both pass the check before either inserts. PostgreSQL can enforce this invariant inside the database with range types and exclusion constraints. Model the interval explicitly A half-open timestamp range includes its start and excludes its end. That lets adjacent bookings touch without overlapping.

Database PostgreSQL