SSRS: Use single transaction when processing the queries

September’s SSRS Classroom Question

Today in our Day 1 SSRS class, a question was posed when we were setting up the Data Source. 

Question: 
“What is the Use single transaction when processing the queries?”

Answer: 
You would use it to reduce the amount of open connections to the database.  For example, if you have a report with 3 datasets and you don’t have this option checked, a new connection is made to the database for every single dataset.  However, if you have it checked, then only one connection will be open to the database and all the datasets will return the data and the connection will be closed.  This can be used to reduce network traffic and potentially increase performance.