What is an Execution Plan?
Query Execution Plans
An execution plan reveals how the relational query optimizer interprets and executes your SQL statement.
Common Plan Operators
| Operator | Performance Interpretation |
|---|---|
| Seq Scan | Full table scan. Inefficient for large tables; missing index. |
| Index Scan | Uses index to find matching rows, then fetches table page. |
| Index Only Scan | All queried columns are inside the index. Fastest lookup! |
| Hash Join | Builds in-memory hash table. Efficient for large unsorted joins. |
| Nested Loop | Iterates outer rows against inner index. Fast for small sets. |