#22608: Migrations optimizer slow (due to double working?)
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Reporter: David S | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: Migrations | Version: master
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Simon Charette):
Things have improved significantly since this ticket was opened 4 years
ago.
`makemigrations` past improvements include
1. Multiple tickets to avoid or delay model rendering during operation's
`state_forwards`.
2. #24554: Sped up migrations by rendering initial apps when they are
first needed
3. #29243: Improve efficiency of migration graph algorithm
the last remaining path that causes slowdown during the `makemigrations`
phase is the model rendering caused by the auto-detector. I just filed a
ticket to cover that in #29899.
The main slowdown during the `migrate` phase is the heavy model rendering
required to pass ''fake'' models to the schema editor. Markus Holtermann
have a long standing
[https://github.com/django/django/compare/master...MarkusH:schemaeditor-
modelstate branch to completely stop rendering models to during the
migration phase]. That includes significant changes to the schema editor
to be able to operate on model states instead of rendered model classes
but it's a good step forward IMO. I just filed a ticket to track this
optimization in #29898.
Not sure if there is anything actionable in this ticket at this point. I'd
suggest we close it and open more focused ones instead.
--
Ticket URL: <https://code.djangoproject.com/ticket/22608#comment:25>
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