When Qlik Sense is installed, the PostgreSQL database also gets installed on the server. This PostgreSQL is used to store the Qlik Sense apps along with other information. Depending on which node architecture you choose to install, you will also need to choose the option for installing the database repository. The two options which you get are Shared Persistence and Synchronized persistence.

From the latest version of Qlik Sense, that is June 2017 release, you won't find the option of synchronized persistence while installing the Qlik Sense, because shared persistence has been made compulsory from this version, but if you are installing prior version, you will get an option while installing to choose any one of them.

Let us have a look at both and their use cases.