Assuming i have 2 models named model_parent and model_child. model_child has a m2o parent_id field referenced to model_parent. Each model has millions of records.

 self.env['model_child'].search([('id', '=', 3), ('parent_id.state', '=', 'done')], limit=1)

 When i execute the search above, odoo searching the parent table with query like that

"select id form model_parent where state = 'search'"

and gathering ids to use in child_model's query. 

"select id form model_child where id = 3 and parent_id in (%s, %s, %s)"

if parent table has millions of records in done state odoo will give millions of ids in second query instead of using id = 3 filter first. If that was a single join query, postgres will handle the search priority by using index but odoo orm not using join queries.

How can i trust dot notation queries in odoo? Is this not a big problem?