#16855: select_related doesn't chain as expected
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Reporter: Leo | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: master
(models, ORM) | Resolution: fixed
Severity: Normal | Triage Stage: Ready for
Keywords: | checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by mrmachine):
Please do not further reduce the functionality of `select_related()` by
removing the no-arguments variant (select all related, with a high hard
coded depth limit to prevent recursive joins).
I use `select_related()` with no arguments all the time, as I have found
that in almost all my use cases, following too many joins and returning
more data than may be necessary is still much more performant than
returning too little data, and subsequently having template authors
generate additional queries by accessing related fields that were not
selected in the view.
It also saves the view programmer from tediously listing larger numbers of
related fields when they legitimately want to select most or all related
fields, and avoids the need for view programmers to know in advance which
related fields a template author will want to access.
I much rather fallback to naming explicit fields in `select_related()`
only when there is an actual performance problem because of too many
joins, instead of premature optimisation by trying to explicitly list all
relations, and having to re-visit that code when a template or model
changes.
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Ticket URL: <https://code.djangoproject.com/ticket/16855#comment:38>
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