SQL Indexes Archives - Page 5 of 6

Don't just blindly create those "missing" indexes!

SentryOne's Aaron Bertrand (@AaronBertrand) discusses a few additional places to get information useful for decisions about creating new indexes that are suggested as "missing" by various tools.

Aaron Bertrand ◆ June 6, 2013

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How filtered indexes could be a more powerful feature

Aaron Bertrand (@AaronBertrand) of SQL Sentry discusses a couple of advantages and a hefty list of limitations with filtered indexes in SQL Server 2008 and above, with links to no less than 36 Connect items!

Aaron Bertrand ◆ April 24, 2013

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The Case of the Cardinality Estimate Red Herring

SQLskills' Joe Sack (@josephsack) walks us through an interesting scenario where we might blame a query performance issue on parameter sniffing or bad statistics, when it actually turns out that a check constraint is the best solution to keep the optimizer honest.

Joe Sack ◆ April 19, 2013

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How expensive are column-side Implicit Conversions?

Jonathan Kehayias (@SQLPoolBoy) demonstrates column-side implicit conversions and the impact they can have on a workload. He concludes that you can only throw hardware at this problem for so long; a design or code change will be necessary to solve the performance issue long-term.

Jonathan Kehayias ◆ April 15, 2013

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Sample Size and the Duration of UPDATE STATISTICS: Does It Matter?

Erin Stellato (@erinstellato) of SQLskills.com tells us about statistics, sample size and the impact different choices can have on duration and subsequent queries.

Erin Stellato ◆ April 10, 2013

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Optimizer Limitations with Filtered Indexes

Paul White (@SQL_Kiwi) makes some great points about limitations in SQL Server's optimizer, and things you need to watch out for, when it comes to filtered indexes.

Paul White ◆ April 4, 2013

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A Look At DBCC CHECKCONSTRAINTS and I/O

Erin Stellato of SQLskills takes a deep look into the I/O impact of running DBCC CHECKCONSTRAINTS, including explaining why some check methods may consume a lot more I/O than others.

Erin Stellato ◆ February 28, 2013

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Should I use NOT IN, OUTER APPLY, LEFT OUTER JOIN, EXCEPT, or NOT EXISTS?

SQL Sentry's Aaron Bertrand (@AaronBertrand) digs into the left anti semi join, comparing NOT IN, NOT EXISTS, OUTER APPLY, EXCEPT, and OUTER JOIN methods.

Aaron Bertrand ◆ December 27, 2012

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Trimming the Transaction Log Fat

In many SQL Server workloads, especially OLTP, the database’s transaction log can be a bottleneck that adds to the time it takes a transaction to complete. Most people assume that the I/O subsystem is the real bottleneck, with it not being able to keep up with the amount of transaction log being generated by the workload.

Paul Randal ◆ December 17, 2012

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The Benefits of Indexing Foreign Keys

Primary and foreign keys are fundamental characteristics of relational databases, as originally noted in E.F. Codd’s paper, “A Relational Model of Data for Large Shared Data Banks”, published in 1970. The quote often repeated is, "The key, the whole key, and nothing but the key, so help me Codd."

In this post, Erin Stellato (@erinstellato) discusses the benefits of adding indexes on top of declared referential constraints.

Erin Stellato ◆ November 20, 2012

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The Zombie PerfMon Counters That Never Die!

One of the things that's simultaneously great and horrible about the Internet is that, once something gets posted out in the ether, it basically never goes away. (Some day, politicians will realize this. We can easily fact check their consistency.) Because of longevity of content posted to the Internet, a lot of performance tuning topics become "zombies." We shoot 'em dead, but they keep coming back!

Kevin Kline ◆ October 17, 2012

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