Databases Intermediate

What is Query Optimization?

The process of improving database query performance through indexing, query rewriting, and schema design techniques.

Query optimization starts with EXPLAIN ANALYZE to understand execution plans. Common optimizations include adding indexes on frequently filtered/joined columns, rewriting subqueries as JOINs, avoiding SELECT *, and using LIMIT for pagination.

Advanced techniques include partial indexes (index subset of rows), covering indexes (include all needed columns), materialized views (pre-computed results), query caching, and connection pooling. Regular ANALYZE ensures the query planner has current statistics.

Related Terms

The default index type in most databases that organizes data in a balanced tree structure for efficient searching, sorting, and range queries.

Prepared Statement

A pre-compiled SQL template that uses parameters instead of literal values, preventing SQL injection and improving performance.

Window Function

An SQL function that performs calculations across a set of rows related to the current row without collapsing the result set.

An advanced open-source relational database known for its reliability, feature richness, and standards compliance.

A database operation that inserts a new row if it does not exist, or updates the existing row if it does.

ORM (Object-Relational Mapping)

A technique that lets you interact with a database using object-oriented code instead of writing raw SQL queries.

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