#32691: Django 3.2 boolean field SQL output is causing a performance regression
in
MySQL.
-------------------------------------+-------------------------------------
Reporter: Todor Velichkov | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Database layer | Version: 3.2
(models, ORM) |
Severity: Normal | Resolution: invalid
Keywords: bool, booleanfield, | Triage Stage:
orm, sql, mysql | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Simon Charette):
If we want to move forward with this change the only possible resolution I
see is to add a `has_native_boolean_type` database feature and set it to
false for MySQL. Another more intrusive alternative would be to have
`BooleanField.get_db_prep_value` return an `int` instead of a `bool` on
MySQL so the lookup machinery is made aware of this quirk instead of
having it magically happen at the database connector layer (`mysqlclient`,
`pymysql`).
In the mean time this can be worked around by doing
`.filter(boolean_field=1)`. Entirely reverting this change would possibly
cause a breakage in all function index on boolean expressions created on
other backends.
In all cases I'd argue that creating an index on a boolean field is a bad
practice particularly when it's backed by a b-tree implementation and your
backend doesn't support partial indices to allow excluding parts of the
covered table as your underlying tree will get heavily unbalanced on way
or the other.
--
Ticket URL: <https://code.djangoproject.com/ticket/32691#comment:8>
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