Query Performance

Metricas a considerar:

Query Cost

Costo de CPU y I/O

Page Reads

Páginas leídas por SQL Server al ejecutar una query.

SET STATISTICS IO ON

Query Execution Time
Se ve afectada por el bloqueo (locks), así como la contención de recursos en el servidor

SET STATISTICS TIME ON

Execution Order (SIN UNION)

1 - FROM, JOIN, APPLY and ON
2 - WHERE
3 - GROUP BY (SUM, AVG, retc)
4 - HAVING
5 - SELECT
6 - ORDER BY
7 - TOP
8 - FOR XML

Execution Order (CON UNION)

1 - FROM, JOIN, APPLY and ON
2 - WHERE
3 - GROUP BY (SUM, AVG, retc)
4 - HAVING
5 - TOP
6 - SELECT and UNION
7 - ORDER BY
8 - FOR XML