QSMQ database and upgrading

[gandalfgray]

Hi

We started to test upgrading from June 2020 p12 to August 2021 and the upgrade failed with error messages when the upgrade tries to CREATE TABLE sensemq

That ofc happen because the table exists.

After dropping the QSMQ database and creating an empty one following https://help.qlik.com/en-US/sense-admin/August2021/Subsystems/DeployAdministerQSE/Content/Sense_Depl...

the upgrade was successful.

The question is if it's safe to do this when we upgrade our Production environment. Any comments on that?

[Gysbert_Wassenaar]

If you want to be really certain you should ask Qlik Support. But I think the QSMQ database can be dropped and recreated without a problem after you've shut down all QS services in preparation for the upgrade.

I usually tend to first do an upgrade to an intermediate release and then upgrade to the version I really want to prevent these kind of upgrade failures. I try not to upgrade directly to a version more than three releases newer than the currently installed one. Although it should work, I've too often encountered an error like you now have.

[gandalfgray]

After some more investigations from our side we saw that the installation was doing a select from the versionhistory table in the QSMQ database, and because our installation did not have a record with version = 1 it tried to create the sensemq table although it already existed, and thus failed.

When we inserted a record with version 1 in the versionhistory table it skipped the create sensemq step and the upgrade was succesful