title: Hikari Unable to acquire JDBC Connection
body: <p>We have Spring-boot/Hibernate/MYSQL application in our project and use Hikari as the connection pool. After a few minutes when our service is started we found the following problem:</p>
  <blockquote>
  <p>org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.dao.DataAccessResourceFailureException: Unable to acquire JDBC Connection; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection</p>
  <p>Caused by: org.springframework.dao.DataAccessResourceFailureException: Unable to acquire JDBC Connection; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection</p>
  </blockquote>
  <p><strong>our config of datasource as follow:</strong></p>
  <hr />
  <p>spring.datasource.type=com.zaxxer.hikari.HikariDataSource</p>
  <p>spring.datasource.hikari.connection-timeout=36000</p>
  <p>spring.datasource.hikari.maximum-pool-size=2</p>
  <p>spring.datasource.hikari.max-lifetime=1800000</p>
  <p>spring.datasource.hikari.idle-timeout=60000</p>
  <p>spring.datasource.hikari.validation-timeout=3000</p>
  <p>spring.datasource.hikari.leak-detection-threshold=240000</p>
  <p>any one here can give me some clue, Thank you!</p>