Difference between Piwik (Web) and Piwik SQL database

If I call Piwik via the web, I get the result 30 for the homepage. If I select the values via SQL from the table “log_visit”, I get 60 records.

Why is there such a big difference? From which table does Piwik (Web) take its numbers?

I have already deleted the following table and then called the period via Web. Piwik created the tables for me again.
But the difference is still there.

Archive_blob_2019_01 , Archive_blob_2019_02 , Archive_blob_2019_03
archive_numeric_2019_01 , archive_numeric_2019_02 , archive_numeric_2019_03_03

What can I do to have this fixed?