pseudo fast_bulk_update

fast_bulk_update.py

 	
	def fast_bulk_update(model, values, fields, batch_size=1000):
	    # pg_specific and only simple values
	    from psycopg2.extras import execute_values
	    model_name = model._meta.db_table
	    assert model_name != 'vals'
	    pk_field = model._meta.pk
	    fields = tuple(model._meta.get_field(field) for field in fields)
	
	    fields_expr = ','.join(field.attname for field in fields)
	    vals_expr = ','.join(f'vals.{field.attname}::{field.db_type(connection)}' for field in fields)
	
	    sql = f'''
	    UPDATE "{model_name}"
	    SET ({fields_expr}) = ({vals_expr})
	    FROM (VALUES %s) AS vals(id,{fields_expr})
	    WHERE vals.id = "{model_name}"."{pk_field.attname}"
	    '''
	
	    fields_with_pk = (pk_field,) + tuple(fields)
	    values = (
	        tuple(field.get_prep_value(getattr(v, field.attname)) for field in fields_with_pk)
	        for v in values
	    )
	
	    with connection.cursor() as cursor:
	        execute_values(cursor, sql, argslist=values, page_size=batch_size)