A digest of great articles originally appearing at SQLPerformance.com. Why Not Seek Predicate Paul White ( b | t ) proves, once again, why he is the best in the business when it comes to debugging a SQL Server query. In this post, Paul gives you a step-by-step breakdown of a query that goes astray due to implied predicate logic. Got a tough query of your own? Post it atanswers.sqlperformance.com! Four Things I Wish I Knew Sooner as a SQL Server DBA Lori Edwards ( b | t ) tells four things she wished she knew before she started her many year career as a SQL Server database … [Read more...]
ICYMI – Predicate Logic, Four Things I Wish I’d Known Sooner, Transact-SQL Bad Habits, Rewriting Queries to Improve Performance
August 4, 2015 by Leave a Comment
ICYMI – Recommended Intel Processors For SQL ’14, Should Indexes Be In The Key Or Included, Comparing Windows Azure VM Performance
July 28, 2015 by 2 Comments
A digest of great articles originally appearing at SQLPerformance.com. Grouped Concatenation in SQL Server and Grouped Concatenation: Ordering and Removing Duplicates In these two related blog posts, Aaron Bertrand ( b | t ) of SQL Sentry takes on the safest and most efficient ways to perform grouped concatenation in SQL Server. Then he follows up with a closer look at some additional requirements for typical grouped concatenation queries in SQL Server.Recommended Intel Processors for SQL Server 2014 Workloads Glenn Berry ( b | t ) of SQLskills continues his series on hardware … [Read more...]
ICYMI – Adding Filtered Indexes, Wait Statistics, Comparing Windows Azure Performance
July 21, 2015 by Leave a Comment
A digest of great articles originally appearing at SQLPerformance.com. Dirty Secrets of the CASE Expression Aaron Bertrand ( b | t ) of SQL Sentry takes a look at some unexpected behavior with the CASE expression and some of its derivatives. Did you know that Aaron is both an uber-genius and a curling fanatic? Improbable, I know. An Unexpected Side-Effect of Adding a Filtered Index Paul White’s ( b | t ) deep dive post explains some of the limitations in the special use and usefully special kind of index, the filtered index. When applied in the appropriate scenarios, filtered indexes … [Read more...]
ICYMI – Read Committed Snapshot Isolation, How Automatic Updates to Statistics Can Affect Query Performance, #temp table
July 14, 2015 by Leave a Comment
A digest of great articles originally appearing at SQLPerformance.com. Read Committed Snapshot Isolation Paul White ( b | t ) has been doing a phenomenal series on SQL Server behavior under each of the major isolation levels. This particular post details the inner workings of READ COMMITTED SNAPSHOT, but there are more articles on this specific isolation level as well. I recommend Paul’s content generally, but this is an especially good series of articles, if you’re not up to speed on isolation levels and how they can alter SQL Server’s default performance. How Automatic Updates to … [Read more...]
ICYMI – Avoiding Performance Tuning, Wait Statistics, Incremental Statistics
July 7, 2015 by Leave a Comment
A digest of great articles originally appearing at SQLPerformance.com. Avoiding Knee-Jerk Performance Tuning Paul Randal of SQLskills.com starts a new series on knee-jerk troubleshooting, discussing many areas where SQL Server folks jump to conclusions when trying to fix a performance issue. Knee-Jerk Wait Statistics: SOS_SCHEDULER_YIELD Paul Randal continues his series on knee-jerk performance troubleshooting. In this post, he talks about SOS_SCHEDULER_YIELD, and how to determine whether it is a wait to worry about in your scenario. SQL Server 2014 Incremental Statistics Benjamin … [Read more...]
ICYMI – Troubleshooting SQL Performance Issues, Missing Indexes, and DROP and TRUNCATE TABLE
June 30, 2015 by Leave a Comment
A digest of great articles originally appearing at SQLPerformance.com. Troubleshooting SQL Server CPU Performance Issues This outstanding article from Joe Sack ( b | t ) of SQLskills.com steps you through a methodical and insightful series of DMVs and queries that can pinpoint CPU issues on your SQL Server instances. Don’t just blindly create those "missing" indexes! Our own Aaron Bertrand ( b | t ) discusses ways to get better and more balanced information used in decisions about creating new indexes than offered as suggestions by native SQL Server tools. The Myth that DROP and … [Read more...]
ICYMI: Parameter Sniffing, Friends with Partition Benefits, and SELECT INTO Parallelism – SQL Server Performance
April 6, 2015 by 2 Comments
Great topics for further reading about tuning SQL Server performance: Exploring SQL Server 2014 SELECT INTO Parallelism Joe Sack (b | t) provides us with a peak into the performance improvements and new behaviors of SQL Server 2014 in the way it can now parallelize large SELECT INTO operations. Parameter Sniffing, Embedding, and the RECOMPILE Options Parameter sniffing is a term used to describe the processes by which SQL Server attempts to reuse execution plans where certain parameters might frequently change. If you’re only familiar in passing with the term, it probably has … [Read more...]
ICYMI: Partitioning Advice, Purging Data Bloat, and an example of TVF Misbehavior – SQL Server Performance
March 30, 2015 by Leave a Comment
Here are some oldies, but goodies that I recommend you read: Two Partitioning Peculiarities and Aggregates and Partitioning Most of us know that partitions are one of the best ways to scale very large databases or very large IO workloads. However, there are risks, two of which are explored in detail by internals master Paul White (b | t). The Price of Not Purging Holding on to data long after its useful lifespan contributes to bloat and added preventative maintenance headaches. Read this informative post from Erin Stellato (b | t), of SQLSkills.com, where you’ll find a lot of useful … [Read more...]
