Sql-Server

Category: sql-server

When Did SQL Server Last Update That Statistic? How Much Has Been Modified Since? And What Columns are in the Stat?

When Did SQL Server Last Update That Statistic? How Much Has Been Modified Since? And What Columns are in the Stat?

Whether I’m working as a DBA, a consultant, a teacher, or just answering questions in my inbox, I always end up needing a script to inspect statistics one way or another.

Here are some freshly written scripts for a classic DBA question: what’s going on in my stats?

Continue reading

Should You Rebuild or Reorganize Indexes on Large Tables? (Dear SQL DBA Episode 19)

Should You Rebuild or Reorganize Indexes on Large Tables? (Dear SQL DBA Episode 19)

The bigger your indexes are, the harder your index maintenance falls. Is it better to rebuild big indexes? Or should you reorganize?

Continue reading

Setting up Free Blocking Alerts and Deadlock Monitoring (Dear SQL DBA Episode 17)

Setting up Free Blocking Alerts and Deadlock Monitoring (Dear SQL DBA Episode 17)

What tools in SQL Server will notify you about blocking and help track the queries behind your toughest blocking and deadlocking problems?

Continue reading

Deadlock Code for the WideWorldImporters Sample Database

Deadlock Code for the WideWorldImporters Sample Database

If you haven’t checked out Microsoft’s new WideWorldImporters sample database for 2016, it’s a pretty cool new little database. The database makes it easy to play around with new 2016 features, and it even ships with some cool little executables to run inserts in the “workload-drivers” folder.

Continue reading

Unique Constraints vs Unique Indexes

Unique Constraints vs Unique Indexes

on September 8, 2016

Unique constraints and unique nonclustered indexes have a lot in common: unique constraints are implemented with a unique index behind the scenes.

While unique nonclustered indexes have a couple of additional features, I can still think of a scenario where it might be best to use unique constraints.

Continue reading

Estimated vs. Actual Number of Rows in Nested Loop Operators

Estimated vs. Actual Number of Rows in Nested Loop Operators

This is one of those little detailsΒ that confused me a ton when I was first working with execution plans.

One problem with learning to work with plans is that there’s just SO MUCH to look at. And it’s a bit spread out. So, even when looking at a single tooltip, things can be confusing.

Let’s talk about the nested loop operator, who can be particularly weird to understand.

Continue reading

Do Clustered Index Columns Count Against Max Nonclustered Key Size?

Do Clustered Index Columns Count Against Max Nonclustered Key Size?

SQL Server 2016 and Azure SQL Database have a lot of little perks. One little thing that changed is that the maximum key size allowed for nonclustered indexes was raised from 900 bytes to 1700 bytes.

Continue reading