JMeter JDBC database testing - Max Wait (ms)

Question

What is the best practice for Max Wait (ms) value in JDBC Connection Configuration? JDBC

I am executing 2 types of tests:

1. 20 loops for each number of threads - to get max Throupught
2. 30min runtime for each number of Threads - to get Response time

With Max Wait = 10000ms I can execute JDBC request with 10,20,30,40,60 and 80 Threads without an error. With Max Wait = 20000ms I can go higher and execute with 100, 120, 140 Threads without an error. It seems to be logical behaviour.

Now question. Can I increase Max Wait value as desired? Is it correct way how to get more test results? Should I stop testing and do not increase number of Threads if any error occur in some Report? I got e.g. 0.06% errors from 10000 samples. Is this stop for my testing? Thanks.

Answer 1

This setting maps to DBCP -> BasicDataSource -> maxWaitMillis parameter, according to the documentation:

The maximum number of milliseconds that the pool will wait (when there are no available connections) for a connection to be returned before throwing an exception, or -1 to wait indefinitely

It should match the relevant setting of your application database configuration. If your goal is to determine the maximum performance - just put -1 there and the timeout will be disabled.

In regards to Is this stop for my testing? - it depends on multiple factors like what application is doing, what you are trying to achieve and what type of testing is being conducted. If you test database which orchestrates nuclear plant operation than zero error threshold is the only acceptable. And if this is a picture gallery of cats, this error level can be considered acceptable.

In majority of cases performance testing is divided into several test executions like:

1. Load Testing - putting the system under anticipated load to see if it capable to handle forecasted amount of users
2. Soak Testing - basically the same as Load Testing but keeping the load for a prolonged duration. This allows to detect e.g. memory leaks
3. Stress testing - determining boundaries of the application, saturation points, bottlenecks, etc. Starting from zero load and gradually increasing it until it breaks mentioning the maximum amount of users, correlation of other metrics like Response Time, Throughput, Error Rate, etc. with the increasing amount of users, checking whether application recovers when load gets back to normal, etc.

See Why ‘Normal’ Load Testing Isn’t Enough article for above testing types described in details.