@heits Okay.
I need to understand how you ended up with 15 minute requests - do you know what was input here?
That's the only interesting part.
What you are showing with 5-50 seconds is exactly what I would expect - with the current bug (no limits).
Metabase has indexed 880k columns over for this database over time. You currently have 172874 columns.
Every time Metabase does sync and sees a new table/column, then it's added to the metadata, and when a table/column is not in the database anymore, then Metabase will set it as active=false instead of deleting it.
You can manually delete all tables and columns from the metadata if you are sure that you don't want them, and they are not linked to questions, which might break. If you had any questions based on these active=false tables/columns, then they wouldn't run anyways.
Make sure you have a backup before you remove them!
You would look in the table metabase_table and metabase_field.
As for the _text - do you have any columns with that type? That's not a valid column type, it should be text.
Check your warehouse information_schema, since it might hint at why it's returning that type to Metabase.