Nested Loops
Short Description
The Nested Loops operator carries out inner joins, left outer joins, left semi joins and left semi anti joins
Detailed Description​
The Nested Loops operator carries out inner joins, left outer joins, left semi joins and left semi anti joins. For each row on the pouter table, a scan is performed on the inner table preferably on an indexed column. Slow nested loops can be caused by a missing index on the join column.
Additional Links​
- Microsoft Documentation - Showplan Logical and Physical Operators Reference
- Microsoft Documentation - Explain Plans
- Plansplaining - Hugo Kornelis' Blog series
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