The jar files for Oracle/MSSQL/MySQL JDBC drivers on MID Servers are in the lib folder, not the JAR Files table, and so can't be swapped out for different versions to be compatible with all versions of those databases - Known Error

The jar files for Oracle/MSSQL/MySQL JDBC drivers on MID Servers are in the lib folder, not the JAR Files table, and so can't be swapped out for different versions to be compatible with all versions of those databases Description The jar files for Oracle/MSSQL/MySQL JDBC drivers on MID Servers are in the lib folder, not the JAR Files table, and so can't be swapped out for different versions to be compatible with all versions of those databases

The JDBC driver files: agent\lib\mssql-jdbc.jar agent\lib\ojdbc6.jar agent\lib\mariadb-java-client.jar

If these did not exist, drivers could simply be added to the JAR files table in the instance for whatever version is needed. That process is documented and supported.

As they do exist, and are in the lib folder and loaded on startup, they will always be used, even if different JAR Files are added as well.

The problem this causes to customers is that these specific versions are not compatible with all versions of the databases they are supposed to connect to. Orchestration, Integration Hub, Import Set Data sources and discovery patterns may fail because of this.

e.g. ojdbc6.jar is "Oracle 11.2.0.3.0 JDBC 4.0 compiled with JDK6 on Fri_Aug_26_08:19:15_PDT_2011"

That has problems connecting to Oracle 8i, which the different version ojdbc8.jar does not, but there is no way to add or swap over the driver. The newer "Oracle 11.2.0.4.0 JDBC 4.0 compiled with JDK6 on Thu_Jul_03_18:17:32_PDT_2014" driver does work, but adding that JAR file to the instance doesn't work due to the /lib folder files taking precedence over /extlib files.

Steps to Reproduce

Connect though a MID Server to one of these 3 databases, where the driver we have causes an exception. Add the JAR File to the instance, and try again, and it will still fail because it is still using the JAR file from the lib folder Manually delete and swap the jar file for one that works, and this will work Upgrade the MID - it will be reverted to the OOTB jar file Workaround After carefully considering the severity and frequency of this problem, and risk of attempting a fix, it has been decided to not address this issue in any current or future releases. We do not make these decisions lightly, and we apologise for any inconvenience.

The workaround is to add the JAR file to the instance, and then change the classpath precedence in the tanukisoftware wrapper of the mid server.

Add the JAR file of the driver to the instance . This will cause it to be synchronised to the agent/extlib folder of the MID Server Open the agent\conf\ wrapper-override.conf file of the MID Server installation in a text editor Add the following 2 lines to the end of that file, and save wrapper.java.classpath.1=extlib/*.jar wrapper.java.classpath.2=lib/*.jar restart the MID Server The jar file in extlib will now be used instead of the file in lib. This workaround will persist after MID Server upgrades, because the wrapper-override.conf file is preserved untouched during upgrades.