Articles

Page 10 of 10 — showing articles 163 to 179 of 179

A Tale of Two Index Hints

Story Time

A detailed look at the differences between the INDEX(0) and INDEX(1) SQL Server table hints.

Inside the Optimizer: Plan Costing

Plan Costing

How the SQL Server query optimizer calculates plan operator costs. Adjusting the cost model with DBCC SETCPUWEIGHT and DBCC SETIOWEIGHT.

Sorting, Row Goals, and the TOP (100) Problem

Row Goals

The Top N Sort operator uses different implementations depending on the number of rows requested. For up to 100 rows it uses replacement selection and will never spill to tempdb.

Row Goals and Grouping

Rowing Goal

Why SQL Server will choose a Hash Match Flow Distinct operator when a row goal is present. Other options for grouping, and when they are chosen.

Inside the Optimizer: Row Goals In Depth

Row Goals in Depth

SQL Server does not always optimize to return the full result set. Various query features can introduce a "row goal", which aims to produce the first few rows quickly.

The Impact of Non‑Updating Updates

Impact

SQL Server optimizations for UPDATE statements that do not change data values. Covers logging, dirty pages, and avoiding the update completely.

Ranking Function Optimizer Transformations

Ranked

SQL Server execution plans for window functions including the Segment Spool plan shape. How you can get a window function plan without writing the OVER clause.