How to specify a constant request sending rate in JMeter?

Question

I'm testing long SQL SELECT queries. Each can take several minutes. I want to gradually increase the number of threads, and observe the behavior of the database.

How to set a constant request sending rate for each thread in Group? For example, each thread sends 2 requests per minute.

As I can see, Constant Throughput Timer ensures requests completion rate (for example, if I specify "2" in the timer, it will slow down the thread so that 2 requests are finished per minute)

My test plan with Constant Throughput Timer

Constant Timer adds a delay after the request completes (not after start), which doesn't fit either.

Answer 1

Constant Throughput Timer is precise enough on minute level, i.e. you will see throughput got applied only for 2nd minute of your test.

There are more precise timers which control the throughput from the very beginning stage of your test:

• Throughput Shaping Timer
• Precise Throughput Timer

Answer 2

It seems you're asking about Open Model, there are few ways to achieve the target rate, but I don't think any one them can config number of request for each thread.

• Open Model ThreadGroup
• Arrivals Thread Group
• Free-Form Arrivals Thread Group