#35015: Update MySQL migration documentation for Mysql 8
------------------------------------------+------------------------
Reporter: Nicolas Lupien | Owner: nobody
Type: Uncategorized | Status: new
Component: Documentation | Version: 5.0
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
------------------------------------------+------------------------
Now that Django dropped support for MySQL 5.7, I think the documentation
is no longer valid.
> MySQL lacks support for transactions around schema alteration
operations, meaning that if a migration fails to apply you will have to
manually unpick the changes in order to try again (it’s impossible to roll
back to an earlier point).
>
> In addition, MySQL will fully rewrite tables for almost every schema
operation and generally takes a time proportional to the number of rows in
the table to add or remove columns. On slower hardware this can be worse
than a minute per million rows - adding a few columns to a table with just
a few million rows could lock your site up for over ten minutes.
>
> Finally, MySQL has relatively small limits on name lengths for columns,
tables and indexes, as well as a limit on the combined size of all columns
an index covers. This means that indexes that are possible on other
backends will fail to be created under MySQL.
--
Ticket URL: <https://code.djangoproject.com/ticket/35015>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/0107018c3abd23d9-5eabbcee-1891-43d9-9e91-d99816168139-000000%40eu-central-1.amazonses.com.
