Initial scanning for tables takes too much time

Hi,
I'm new to Metabase and I'm facing an issue while connecting to DB.

I have a Metabase instance hosted on AWS EC2 machine,
We are using the latest version of Metabase and Java11.
When Metabase connects to the DB for the first time, the initial scan takes too much time without any clear logs or errors.

The DB is Oracle 11g uses driver ojdbc8, and we are using read only user who has access to few tables, but some of these tables are huge.

My first question, is it normal to take a very long time when some of these tables are large, like 12 hours and still not finished, and is there a way to avoid the initial scan for the meta data?

Thanks in advance.

12 hours doesn't sound right.
What's happening at the Oracle end? Can you see lots of activity?