Database engineer

Elias Rowe

Elias Rowe writes about database engineering, SQL performance, and production systems. He focuses on measurable behavior, practical trade-offs, and conclusions that can be reproduced rather than assumed.

PostgreSQL · MySQL · Query optimization · Data modeling · Production operations

PostgreSQLAug 23, 20263 min read

Why an Index Is Not Used: the Estimate, Not the Index

An index the planner ignores is usually a row-estimate problem. The fix starts with what the optimizer expected, not with the index definition.

#query-optimization
#indexing
#execution-plans
#statistics