Simple SQL blow up metabase.db.mv.db to >3GB

When i do simple SQL statemens ‘example: select * from table’ the metabase.db.mv.db will be extemely big. nearly 4GB.
Than the metabase will be extremely slow. The result is, i have to take the old db-backup and restore it.

I use the latest Version, but i’m not very happy with it.

What can i do?

I usually create another user for metabase with only read access to only required tables/views. MB may try to investigate all the columns of all the tables in the db in the background.

Migrate from H2 to MySQL or Postgress. You won’t regret it.

Not possible. We use IBM iSeries Servers and DB2 database.

H2 isn’t recommeded for live, only test. I don’t know anything about iSeries, but you need to think about having a Linux or Windows server running MySQL to store Metabase’s data. Would only need to be a tiny VM.