Problem
No indexes = slow queries. Too many indexes = slow writes, bloat. Wrong indexes = unused, misleading EXPLAIN plans.
Also known as: index-design, query-optimization, b-tree, partial-index, covering-index
Design indexes that accelerate queries without killing write performance, using covering indexes, partial indexes, and query-driven design.
No indexes = slow queries. Too many indexes = slow writes, bloat. Wrong indexes = unused, misleading EXPLAIN plans.
Low — disk, memory
Medium — review, bloat monitoring, REINDEX
High — query plans, column order, selectivity
Unused indexes: write cost, no read benefit
Missing index: sequential scan on large table
Wrong column order: index not used
Statistics stale: planner chooses seq scan
Lock contention: `CREATE INDEX` without CONCURRENTLY