SQLAlchemy 2.0 not supported when task history enabled

[fran-penedo]

As far as I can tell, the issue is in the _upgrade_schema function. In 2.0, string queries must be enclosed in a text object and for some reason the rows returned in conn.execute(sqlalchemy.text('PRAGMA table_info(task_parameters);')).fetchall() have no keys. I do not know if there are other changes in 2.0 that will break functionality.

[plazmakeks]

can be avoided by pinning sqlalchemy to

sqlalchemy==1.4.46

but you probably found it out by your own. however it's crazy that this is not addressed by the maintaining team. it's takes like 1 minute to fix it.

[saikrishna130]

If I want to use "oracledb" which is available in sqlalchemy==2.0.7, _upgrade_schema wont allow the sql execution in plain text format. Instead, it requires to be as conn.execute(sqlalchemy.text('ALTER TABLE task_parameters MODIFY value TEXT'))

[metazool]

#3267 - there's an open PR for this which looks held up on a decision as to whether to drop python 3.6 support in luigi, which support for sqlalchemy 2.X would involve...