![]() Now when you run this the way I have this in this demo with no limitations on it at all, it clears out the entire procedure cache on your instance. The very first thing that we’re going to do in this demo is something that can be a little problematic to do sometimes, we’re clearing out the execution plan cache by running DBCC FREEPROCCACHE. We are going to watch some recompile hints. You get query plan and aggregate information in Query Store, even if you have recompile in the header of a procedure. Good news: recompile hints don’t obscure past performance in Query Store (available in SQL Server 2016+) like they do in the plan cache. Gail Shaw has an article that goes deeper into this topic: hit and miss. Since most applications that use procedures specify the command type, I used a PowerShell script to reproduce that behavior. ![]() If you execute a stored procedure in SQL Server Management Studio (or if you don’t specify the command type as a procedure), SQL Server first considers your execution statement itself as a potential adhoc plan because it appears as just text. That makes the compilation-related counters look different. I used a PowerShell script in this demo because it allows me to call a stored procedure like an application does, with a specific command type that indicates it’s a stored procedure right off. You’ll learn more granular ways to clear out parts of your execution plan cache in the upcoming module on “How to ‘take out’ an execution plan” Why a PowerShell script? Then compare their performance, both from the client application and in the SQL Server plan cache… if you can! Being more gentle to the plan cache She primarily focuses on the database domain, helping clients build short and long term multi-channel campaigns to drive leads for their sales pipeline.See different kinds of recompile hints in action Nupur Dave is a social media enthusiast and an independent consultant. If you need help with any SQL Server Performance Tuning Issues, please feel free to reach out at is also a CrossFit Level 1 Trainer (CF-L1) and CrossFit Level 2 Trainer (CF-L2). Pinal is an experienced and dedicated professional with a deep commitment to flawless customer service. To freely share his knowledge and help others build their expertise, Pinal has also written more than 5,500 database tech articles on his blog at. Pinal has authored 13 SQL Server database books and 40 Pluralsight courses. He holds a Masters of Science degree and numerous database certifications. Pinal Dave is an SQL Server Performance Tuning Expert and independent consultant with over 17 years of hands-on experience. SQL SERVER – 2017 – Script to Clear Procedure Cache at Database Level.SQL SERVER – Plan Cache – Retrieve and Remove – A Simple Script.SQL SERVER – Script to Get Compiled Plan with Parameters From Cache.SQL SERVER – Remove All Query Cached Plans Not Used In Certain Period.SQL SERVER – Stored Procedure – Clean Cache and Clean Buffer.SQL SERVER – Plan Cache and Data Cache in Memory.SQL SERVER – Finding The Oldest Query Plan From Cache.SQL SERVER – List Query Plan, Cache Size, Text and Execution Count.Here are a few relevant blog posts on the same topic, which you may find interesting. When you use SQL_NO_CACHE and OPTION (RECOMPILE), the relational databases (MySQL and SQL Server respectively) are directly retrieving the data from the disk rather than what is stored in the cache. OPTION(RECOMPILE) MySQL Query SQL_NO_CACHE SELECT SQL_NO_CACHE Columnname SQL Server Query – OPTION (RECOMPILE) SELECT Columnname Let us see how we can write a query where we will not use the cached results but directly get our data from the SQL Server disk and not from the cache. ![]() Both of the relational databases takes advantages of the memory cache to return us the data. Let us see two different examples today for MySQL and SQL Server. We discussed during the Comprehensive Database Performance Health Check. I had a very interesting conversation with my client on the topic of how to retrieve queries, not from the cache for MySQL and SQL Server, we discussed SQL_NO_CACHE and OPTION (RECOMPILE). They are also using lots of different caching solutions for their business as well as top of the line hardware. One of my large banking clients uses multiple databases for its doing various different transactions. As a developer and DBA who often has preferred technology but if we are running a large organization, we have to be more accommodating to all the technologies.
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