Rationale
---------
Given the following domain:
['|',
('company_id.name', 'like', 'BE'),
('company_id.city', 'like', 'Brussels')]
The ORM would generate the following SQL query:
SELECT "res_partner"."id"
FROM "res_partner"
WHERE "res_partner"."company_id" IN (
SELECT "res_company"."id"
FROM "res_company"
WHERE "res_company"."name" like 'BE'
) OR "res_partner"."company_id" IN (
SELECT "res_company"."id"
FROM "res_company"
WHERE "res_company"."email" like 'help@odoo.com'
);
Which is sub-optiomal as the WHERE clause of the two subqueries could be
regrouped inside of a single query like so:
SELECT "res_partner"."id"
FROM "res_partner"
WHERE "res_partner"."company_id" IN (
SELECT "res_company"."id"
FROM "res_company" WHERE (
"res_company"."name" like 'BE'
OR "res_company"."email" like 'help@odoo.com'
)
);
Postgres-wise, it is faster to execute the latter query than the former
one. This commit is about optimizing the ORM so that it generates
queries where the WHERE clause of compatible subqueries are grouped
together.
Technical solution
------------------
The solution explored by this work is to replace the regular relational
field accesses (over a dotted path) by a new `any` operator that look as
follow:
(relational_field, 'any', domain)
For instance, the above `('company_id.name', 'like', 'BE')` leaf becomes
`('company_id', 'any', [('name', 'like', 'BE')]` using `any`.
Having a domain as right-hand-side allow for the combination of the
domains of same compatible relations:
[('company_id', 'any', ['|',
('name', 'like', 'BE'),
('city', 'like', 'Brussels')])
Having combined domains allows for generating better SQL queries with
minimal changes to the expression parsing algorithm, which can only
translate a single leaf at a time to SQL. With the new `any` operator,
it is still a single leaf but the right-hand-side contains the merged
domain, thus the combined SQL WHERE clause is immediately generated.
task-id-3234671
Part-of: odoo/odoo#118067
Co-authored-by: Raphaël Collet <rco@odoo.com>
