#33154: The Exact lookup generates suboptimal queries for BooleanField on MySQL
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Reporter: Roman | Owner: nobody
Miroshnychenko |
Type: | Status: new
Uncategorized |
Component: Database | Version: 3.2
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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Currently `Exact` lookup uses "shortcut" condition syntax for
`BooleanField`, that is `WHERE foo` or `WHERE NOT foo` instead of explicit
syntax `WHERE foo = TRUE/FALSE` if `foo` is a BooleanField (`TINYINT(1)`
in MySQL).
The problem is that with "shortcut" syntax MySQL query planner ignores DB
indexes that include the field in question in contrast to explicit
condition syntax, resulting in performance hit for ORM-generated SQL
statements.
Proposed solution: Always use explicit comparison syntax in `Exact` lookup
for `BooleanField` with MySQL as a DB backend, that is `WHERE foo =
TRUE/FALSE` or even `WHERE foo = 1/0` since boolean is `TINYINT(1)` in
MySQL.
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Ticket URL: <https://code.djangoproject.com/ticket/33154>
Django <https://code.djangoproject.com/>
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