Thinking About Compile Time

Jay Robinson has a post on compilation time and especially indexed views:

What I found was that worker time needed to compile these queries is indistinguishable from that needed to execute them. To show this, let’s look at an example in AdventureWorks2014. In this example, I’m going to create and execute two similar procedures. I’m also going to create a number of indexed views.

Why indexed views? I want to increase compile time significantly for this exercise, and a large number of indexed views can do that. From MSDN: “The query optimizer may use indexed views to speed up the query execution. The view does not have to be referenced in the query for the optimizer to consider that view for a substitution.” My thanks tooas_public on stackoverflow.com for that tip.

Indexed views come at a cost, as Jay shows.

Related Posts

Join Elimination

Lukas Eder has a nice post explaining different forms of automatic join elimination: We intended to fetch all customers and their addresses. But observe: We project only columns from the CUSTOMER table and we don’t have any predicates at all, specifically not predicates using the ADDRESS table. So, we’re completely ignoring any contributions from the ADDRESS table. We never really needed […]

Read More

The Pain Of Multi-Statement TVFs

Andy Mallon walks through a multi-statement table-valued function in Microsoft Dynamics CRM: Look at all those table-valued function calls! Followed immediately by a really expensive hash match. My Spidey Sense started to tingle. What is fn_GetMaxPrivilegeDepthMask, and why is it being called 30 times? I bet this is a problem. When you see “Table-valued function” as an operator […]

Read More

Categories

November 2016
MTWTFSS
« Oct Dec »
 123456
78910111213
14151617181920
21222324252627
282930