Category: Performance

• Optimizer, what if I had more CPUs?

  

  2012-03-27 - General, Performance, SQL Server Internals

  In the March issue of SQL Server Pro Itzik Ben-Gan wrote about an undocumented DBCC command that was recently discovered in the wild by Eladio Rincon (http://www.sqlmag.com/article/sql-server/options-affecting-parallelism-141505). Itzik closed the article by expressing his hope to get this statement documented [more…]

• Key Lookup Operator in Update Statements

  

  2012-03-20 - General, Performance, SQL Server Internals

  When thinking about the indexes for update statements it is easy to overlook an important peculiarity in the way SQL Server finds the rows to update before updating them. Those pesky Lookups If you have an UPDATE statement that filters [more…]

• The Story of the Evil Assert Operator

  

  2012-03-06 - General, Performance, SQL Server Internals

  Today I am going to talk about the evil side of the Assert Operator. To start out, let me introduce this operator to you: The Assert Operator The Assert Operator is used by SQL Server in execution plans that require [more…]

• Why CXPACKET Waits are not your Performance Problem

  

  2012-02-28 - General, Performance, SQL Server Internals

  There is a lot of information out there recommending to do this or that to deal with the performance problems that you must have if you see CXPACKET waits. All these recommendations build on the notion that the CXPACKET wait is [more…]

• Purge Problems [TSQL Tuesday #027 – The Big Data Valentine’s Edition]

  

  2012-02-14 - General, Performance, T-SQL Tuesday

  T-SQL Tuesday #27 is hosted by Steve Jones (blog|twitter). This month’s topic is “Big Data”. Purge Problems in Big Data – Not only a SELECT needs an index Recently I was called to an issue at a 5+ TB customer. [more…]