[FIX] expression: simplify sub-searches order

Performance fix: when parsing domains using special operators
(`child_of`, ...), or with dotted field on the left value
(`['partner_id.name', ...]`), the ORM starts by a first call on
`search()` and builds a new domain so the final query has "IN (<ids
found by sub-search>)".

The sub-search issued on the comodel uses the default "order by".
The order of the ids is irrelevant here, we only need to know the ids.

A good example is when the sub-search happens on `product.product`,
which is ordered by `default_code, name, id`. The field `name` is
inherited and translated, so the ordering requires a JOIN on
`product_template` and a LEFT JOIN on `ir_translation`. Ordering by `id`
avoids these 2 JOINs.

Some discussion took place about modifying `_generate_order_by()` to
remove the `ORDER BY` clause when the `order` argument is False or ''.
Apart the fact that it would be a breaking change, @odony has shown that
sorting by `id` is so cheap that removing the `ORDER BY` might not
bring significant performance boost [0].

[0] https://github.com/odoo/odoo/pull/52368#issuecomment-646643773

opw-2270690

closes odoo/odoo#53629

X-original-commit: fc91f7b4e8f9f8a95862df1ce95a9639cf7d1363
Signed-off-by: Nicolas Lempereur (nle) <nle@odoo.com>
Signed-off-by: Raphael Collet (rco) <rco@openerp.com>

0 files changed, 0 insertions, 0 deletions