What is isolation level of autocommit?
The default isolation level is controlled through default_transaction_isolation and is read committed in a standard installation.
You can check your current setting using:
show default_transaction_isolation;

As Postgres does not support (or implement) read uncommitted there is no need to change this &quot;away from read uncommitted&quot;.
If you want to change the isolation level to &quot;higher&quot; one, even in autocommit mode, you can use:
set default_transaction_isolation = serializable;

The above will change the default for the current session (=connection).