Have you ever wondered how the @@idle function works in SQL Server? It can be a bit confusing to interpret the number it returns. In this article, we will explore the @@idle function and its companion function, @@timeticks, to gain a better understanding of how they work.
Before we dive into the details, let’s define these two functions:
- @@IDLE: This function returns the number of time ticks that SQL Server has been idle since the last restart of SQL Server services. It provides a cumulative value for all the CPUs available to SQL Server.
- @@TIMETICKS: This function returns the number of microseconds per time tick. The value of each tick for SQL Server on Windows is 31.25 milliseconds.
Now, let’s see a quick demonstration of how these functions work together:
SELECT @@IDLE AS 'Idle (Unit: Ticks)',
@@TIMETICKS AS 'Ticks (Microseconds per tick)',
@@IDLE * CAST(@@TIMETICKS AS FLOAT) AS 'Idle (Unit: Microseconds)'
The above query will give us the system idle time in ticks and microseconds. By multiplying the idle time with the time tick value, we can calculate the idle time in microseconds.
So, why is this information useful? Well, understanding the system idle time can provide insights into the performance and resource utilization of your SQL Server. By monitoring the idle time, you can identify periods of low activity and potentially optimize your server’s configuration or workload.
Now that you know about the @@idle function, I’m curious to hear if you were aware of this function before reading this article. Do you know any other interesting usage of system functions in SQL Server? Please leave a comment below, and I’ll be sure to publish it on the blog with due credit.