Error: "Unable to acquire JDBC Connection" after updating the DLP server OS

Products

• Data Loss Prevention
• Data Loss Prevention Enforce
• Data Loss Prevention Oracle Standard Edition 2

Issue/Introduction

The DLP Enforce services failed to connect to the Oracle Database after a series of Windows updates or patching.
The Enforce services do not start after a Windows update and server restart.

Errors in the DLP services logs: 

Caused by: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:400)

Caused by: java.sql.SQLRecoverableException: IO Error: Got minus one from a read call
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:743)
org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:106)

Cause

The DBA found that the DLP login sessions from Enforce server to the DB, were not logged off when the OS updates were installed.
This caused the database to not accept further connections.

Resolution

Follow the best practice of stopping or disabling the Enforce services before any server OS maintenance.