Spring Boot HikariCP 连接池频繁报错 Connection is not available 如何解决？

Question

springboot采用默认连接池hikaricp，系统在线上运行后，经常会突然大批量报错：nested exception is org.apache.ibatis.exceptions.PersistenceException:
error-1001.log-### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLTransientConnectionException: HikariPool-1 - Connection is not available, request timed out after 5009ms

数据库用的是Oracle 11g。

这种情况是偶然的，不是一直出现，一旦出现就会大批量报错。

我开启debug日志后，发现有如下错误：

• Failed to validate connection oracle.jdbc.driver.T4CConnection@1c16e38e (关闭的连接). Possibly consider using a shorter maxLifetime value.
• Closing connection oracle.jdbc.driver.T4CConnection@1c16e38e: (connection is dead)

• Failed to validate connection oracle.jdbc.driver.T4CConnection@65814e22 (关闭的连接). Possibly consider using a shorter maxLifetime value.

• Closing connection oracle.jdbc.driver.T4CConnection@65814e22: (connection is dead)

  • Failed to validate connection oracle.jdbc.driver.T4CConnection@739a232f (关闭的连接). Possibly consider using a shorter maxLifetime value.

• Closing connection oracle.jdbc.driver.T4CConnection@739a232f: (connection is dead)

  • Failed to validate connection oracle.jdbc.driver.T4CConnection@1c0ea44b (关闭的连接). Possibly consider using a shorter maxLifetime value.
  • Closing connection oracle.jdbc.driver.T4CConnection@1c0ea44b: (connection is dead)
  • Failed to validate connection oracle.jdbc.driver.T4CConnection@402488c1 (关闭的连接). Possibly consider using a shorter maxLifetime value.
  • Closing connection oracle.jdbc.driver.T4CConnection@402488c1: (connection is dead)

  Timeout failure stats (total=31, active=0, idle=31, waiting=0)

我对连接池参数做出各种调整，比如调低maxLifetime，修改，均无作用。系统访问量很低，orm用的mybatis，每个接口的查询速度非常快。

Answer 1

看着是获取连接超时了，缩小一下minimum-idle，亦或是调小一下 idle-timeout