# query planner

CEFR C2 · Compound

Source: https://englishreference.com/word/query-planner
Updated: 2026-07-22

## Definition

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.

For teachers: 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.

## Examples

- 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.

## Usage notes

- Commonly used in the context of SQL databases and data engineering.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.