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.

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PostgreSQL Administration & Performance Tuning

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Related Terms

An open-source, in-memory data store used as a database, cache, message broker, and queue with sub-millisecond response times.

A category of databases that store data in non-tabular formats, optimized for specific data models and access patterns.

EXPLAIN ANALYZE

A PostgreSQL command that shows the execution plan of a query along with actual runtime statistics for performance tuning.

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

Row-Level Security (RLS)

A database feature that restricts which rows a user can access in a table based on security policies.

Window Function

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

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