PostgreSQL indexing basics for web developers

Indexes are the most powerful speed-up many web developers rarely touch — until things slow down.

# Read EXPLAIN first

Before adding an index, use EXPLAIN ANALYZE to see what the query actually does and where the bottleneck is.

# Index columns you filter on

Columns in WHERE, JOIN, and ORDER BY are prime candidates; but indexes also cost you on writes.

• Don't index everything — balance reads/writes
• Consider composite indexes for multi-column queries
• Track unused indexes and clean them up

Understanding your data matters more than memorizing every index type.