Databases Intermediate

What is EXPLAIN ANALYZE?

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

EXPLAIN ANALYZE runs a query and shows how the database executed it: which indexes were used, join methods, row estimates vs actuals, and timing. This is the primary tool for query performance optimization.

Key things to look for: sequential scans on large tables (may need indexes), large differences between estimated and actual rows (statistics may be outdated), and nested loop joins on large datasets (may need different join strategy).

Related Terms

Database Sharding

A horizontal scaling strategy that distributes data across multiple database servers based on a partition key.

The structure definition of a database including tables, columns, data types, relationships, indexes, and constraints.

PostgreSQL's binary JSON data type that stores JSON documents with indexing, querying, and manipulation capabilities.

Connection Pool

A cache of database connections that can be reused, avoiding the overhead of creating new connections for each request.

Query Optimization

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

Structured Query Language — the standard language for managing and querying data in relational databases.

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