Microsoft: SQL Performance Benchmark

1.  Batch Requests/Sec
Batch Requests/Sec measures the number of batches SQL Server is receiving per second. This counter is a good indicator of how much activity is being processed by your SQL Server box. The higher the number, the more queries are being executed on your box. Like many counters, there is no single number that can be used universally to indicate your machine is too busy. Today’s machines are getting more and more powerful all the time and therefore can process more batch requests per second. You should review this counter over time to determine a baseline number for your environment.

2.  SQL Compilations/Sec
The SQL Compilations/Sec measure the number of times SQL Server compiles an execution plan per second. Compiling an execution plan is a resource-intensive operation. Compilations/Sec should be compared with the number of Batch Requests/Sec to get an indication of whether or not complications might be hurting your performance. To do that, divide the number of batch requests by the number of compiles per second to give you a ratio of the number of batches executed per compile. Ideally you want to have one compile per every 10 batch requests.

3.  SQL Re-Compilations/Sec
When the execution plan is invalidated due to some significant event, SQL Server will re-compile it. The Re-compilations/Sec counter measures the number of time a re-compile event was triggered per second. Re-compiles, like compiles, are expensive operations so you want to minimize the number of re-compiles. Ideally you want to keep this counter less than 10% of the number of Compilations/Sec.