SQL Server Performance & Troubleshooting – Where Milliseconds Matter 🚀

Hello friends!  If yesterday you read my post and found it definitely boring (for the topic of course and not for how it was written to the author 😁) well today I promise you that the topic will be much more interesting! Let's talk about Sniffing , let's talk about going to see what happens when we "log in" or when we send a Query to SQL Server.  We will do this by taking a look to the little known tabular data stream (TDS) protocol built on top of the TCP/IP protocol. Ready! The TDS protocol What is the Tabular data stream (TDS) protocol?  The TDS is the protocol used by the SQL Server client Net-Library to communicates with SQL Server . TDS is specific to SQL Server and it is a low-level protocol that specifies both commands and data in a specific arrangement.  TDS encapsulate the TCP/IP protocol. Sniffing TDS packets you can read from the network the requests that your application do to the SQL Server and read the answer .   How to Sniff data from the ne...

Hi Guys! First of all I must say a big t hank you for the first five thousands visualizations of this my Blog . I am really very proud of it! Thank you so much!   Today i will show you how to create a Plan Guide in order to resolve, for example, parameter sniffing issues . I hope you enjoy this post! Introduction It was November when we spoke about parameter sniffing (read here. ) We have seen that parameter sniffing is not necessary a bad thing. Parametrization sniffing, instead, could be a problem if your data is distribuited unevenly! Today for this first post of february I will show you a way to solve this problem through the creation of a Plan Guide However, before talking of Plan Guide, we do also a small summary about unevenly distributed data . Let's start! Recap about not evenly distribuited data Suppose we have two tables where we store our orders. OrdTes represents the header of the documents while OrdRig its rows. A document can have on...

Hi Guys, What I want to do today is an experiment . In fact this is my first article written in English. I don't know at the moment if it will be the last. But what is certain is that, as usually, i will try to tell you each topic in a simple and clear way! Enjoy the reading! In my previous article i showed you a little tip , today instead i will tell you a little about theory. We will talk about parameterization and a phenomenon called parameter sniffing . But now to introduce the topic lets start with... The history of the execution of a Query Today's question is?   What happens when i run a query? Well, as you can imagine, solving a query is a process that requires many steps. These steps, how can be see from the drawing below, are: The Parsing phase The first of these steps is called parsing . During the parsing (the parser) checks our T-SQL String for proper syntax (eg. you write the words " SLECT " or " FRON ") At the ...