query planner
compound.compound. a part of a database system that finds the fastest way to get the data you asked for. It looks at different paths and chooses the one that takes the least time or computer power.
compound. a component of a database management system that determines the most efficient execution plan for a given structured query. It evaluates multiple access paths and join algorithms to minimize resource consumption and latency.
The query planner chooses the best index to use.
When the database slowed down, the developers checked the query planner to see why it was performing a full table scan instead of using an index.
Advanced query planners utilize cost-based optimization, weighing factors like disk I/O and CPU cycles against statistical metadata to select an optimal execution strategy from a vast search space of possibilities.
A compound of the noun query, derived from the Latin quaere, and the agent noun planner, formed from the Middle French plan. The term emerged as a standard compositional description within relational database theory during the 1970s.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Commonly used in the context of SQL databases and data engineering.
Last updated July 22, 2026