This repository contains a test for HikariCP's closing of MySQL unclosed connections at data source shutdown.
See brettwooldridge/HikariCP#206
The test.Configuration class contains the database connection parameters, which must be changed and pointed to
a working MySQL server in order to execute the test. Any SELECT query will be OK.
The test.MySQLTest in the src/test/java folder contains the JUnit test that can be used for running the test,
specifically its runIter() test method will be of interest for profiling. It will execute the TestRunner 100
times and then wait for 60 seconds hoping that some connections get closed in that interval.
The test.TestRunner class creates a HikariDataSource with the configuration in test.Configuration, executes
5 queries on it (5 different connections) and then shuts the data source down.
The test.QueryExecutor class executes the query and leaves the connection unclosed on purpose.
Observed result is that unclosed MySQL connections never get closed after data source shutdown. Even if we extend the wait period at the end of the test to 10 minutes, nothing happens.