Query-Performance

Category: query-performance

3 Tricks with STATISTICS IO and STATISTICS TIME in SQL Server

3 Tricks with STATISTICS IO and STATISTICS TIME in SQL Server

When  you need to measure how long a query takes and how many resources it uses, STATISTICS TIME and STATISTICS IO are great tools for interactive testing in SQL Server. I use these settings constantly when tuning indexes and query.

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Learn Indexing from Kendra in Huntington Beach on April 1 for $99!

Learn Indexing from Kendra in Huntington Beach on April 1 for $99!

on March 18, 2016

It’s just two weeks until I’ll be teaching index tuning in Huntington Beach, California.

This day long session is $99 – and it’s a great time of year to plan a quick visit to California, no?

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Live Query Statistics Do Not Replace Actual Execution Plans

Live Query Statistics Do Not Replace Actual Execution Plans

I like SQL Server’s new Live Query Statistics feature a lot for testing and tuning large queries. One of my first questions was whether this could replace using actual execution plans, or if it’s useful to use both during testing.

Finding: Both are useful. And both can impact query performance.

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The Case of DATETIME2 and Partition Elimination

The Case of DATETIME2 and Partition Elimination

on March 10, 2016

Data types are hard.

I’ve been working on some demo code for table partitioning. I have a table partitioned by a column named FakeBirthDateStamp, which is a DATETIME2(0) column. The table is a partitioned heap. At this point in the demo, I hadn’t built any indexes. I wanted to show that partition elimination could occur on a partitioned table, even without a clustered index.

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What Resets sys.dm_db_index_usage_stats and Missing Index DMVs?

What Resets sys.dm_db_index_usage_stats and Missing Index DMVs?

Managing indexes got trickier with SQL Server 2012. SQL Server has tracked and reported statistics on how often indexes are used and requested since SQL Server 2005. As of SQL Server 2012, suddenly all that information started getting reset whenever anyone ran ALTER INDEX REBUILD.

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SQL Server YEAR() Function and Index Performance

SQL Server YEAR() Function and Index Performance

on March 1, 2016

SQL Server’s really clever about a lot of things. It’s not super clever about YEAR() when it comes to indexes, even using SQL Server 2016 – but you can either make your TSQL more clever, or work around it with computed columns.

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Incorrect Results: Why You Should Not Ignore Patches for SQL Server

Incorrect Results: Why You Should Not Ignore Patches for SQL Server

on February 22, 2016

Patching isn’t fun. It’s time consuming, thankless, and easy to break stuff.

But you can’t skip it. For critical systems, you need to subscribe to patch lists for SQL Server and review issues that are fixed regularly.

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