Driver version

7.4.1, 8.4.1

SQL Server version

Azure SQL Managed Instance

Client Operating System

Windows Server 2016 amd64 10.0

JAVA/JVM version

Oracle Corporation version 1.8.0_131 64-bit

Problem description

Java application randomly crashes with assertion error when accessing Azure SQL Managed Instance using integrated authentication. The assertion error happens inside sqljdbc_auth.dll (for driver version 7.4.1). When upgrading the JDBC driver and DLL, the same assertion failure is shown for mssql-jdbc_auth-8.4.1.x64.dll.

The issue happens randomly, typically several times a day. It may depend on total volume of connections/queries being executed.

1. Expected behaviour:
   No assertion failures.

2. Actual behaviour:
   Assertion failure popup when running as command-line. Application crashes when running as Windows service.

3. Error message/stack trace:
   No errors are reported from JDBC driver and no errors in log files.

Here is a screenshot of assertion popups:

4. Any other details that can be helpful:

We are using 64-bit Java 1.8 and SQL Server JDBC driver.

Client application is basically a multithreaded web server, each thread running SQL Server queries using JDBC driver. A new connection is opened for every query being run.

We are using Windows integrated security with Authentication=ActiveDirectoryIntegrated setting. The application is connecting to Azure SQL Server Managed Instance in a federated environment. There are no issues when connecting to on-prem SQL Server.

JDBC trace logs

We are trying to get more information on this assertion: #1429

Reproduction code

It's not easy to reproduce in a test application due to sporadic nature of this failure.