DatabasesIntermediate
EXPLAIN Plan
Pronunciationiks-PLAYN plan
Definition
A step-by-step roadmap generated by a database engine showing how it will execute a query, including which indexes and joins it plans to use.
Where you hear it
Database optimization discussions, slow query troubleshooting, and performance tuning sessions.
Examples
Run
EXPLAIN SELECT * FROM users WHERE email = 'test@example.com';to see if the query uses the email index.The execution plan showed a full table scan, which explained why the report query was so slow.
Common mistake
Assuming the database will always execute the query exactly as written, without realizing the engine might completely rearrange operations based on the plan.