Hi,
If the synchronization is taking more than 1 hour it could be due to some connectivity issues. I would perform the following checks in order to findout if the cause is a network issue or not:
* I would check if running queries from the same host where the Data Catalog is installed, to the external database used for the metadata database works as expected.
* I would also check if the performance of those queries is as expected by [creating a data source in the Virtual DataPort server](https://community.denodo.com/docs/html/browse/8.0/en/vdp/administration/creating_data_sources_and_base_views/jdbc_sources/jdbc_sources#jdbc-sources) (if it is installed in the same host as the Data Catalog). I would create and run some base views on top of it and check if the performance is expected.
Suppose if you still need help and if you are a valid support user then you can raise a support case on [Denodo Support Site](https://support.denodo.com) so that our support team can help you.
Hope this helps!
