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6f088bb5c5
In some instances the communities migration would be skipped but not marked as `dirty`. This commit addresses the issue by: - Making sure that if dirty is set the migration is not skipped but replayed - If the version is on the communities migration and dirty is false, we check for the presence of the communities table. If not present we replay the communities migration. - Make community_id field in user_messages nullable It also removes all the `down` migration, as we can't use them effectively, as explained in the README.md added.
14 lines
554 B
Markdown
14 lines
554 B
Markdown
### How to write migrations?
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We only write `up` migrations, `down` migrations are not always possible in sqlite or
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too complex/too expensive. For example to remove a column you would have to duplicate
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the table, copy over the data, delete and recreated.
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This can be very expensive for some tables (user_messages for example), so should not be attempted.
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### Notes
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One issue we faced multiple times is that updates to `user_messages` can be very
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expensive, leading to slow upgrade times and interrupted migrations. So avoid
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writes if not necessary.
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