django-dbbackup: Error: constraint does not exist when restoring a backup on a fresh db

Backed up the database
Restored the database from the backup

=> Works fine ✅

Back up the database
Wipe out the database
Do the initial django migrate
Restore the same backup as in the previous case

=> I get the following error ❌

ERROR:  constraint "socialaccount_socialapp_site_site_id_2579dee5_fk_django_site_id" of relation "socialaccount_socialapp_sites" does not exist

I guess the issue comes from constraint name not being constant (2579dee5 par above).

Why not use IF NOT EXIST (https://www.postgresql.org/docs/9.0/static/sql-altertable.html) ? Or simply wipe out the whole database before importing and remove all the DROP commands?

I guess I miss some historical data (reasons behind decisions), but for now I have a hard time figuring how to restore this dump without manual edit of the relevant lines.

About this issue

Original URL
State: open
Created 7 years ago
Reactions: 4
Comments: 33 (7 by maintainers)

Most upvoted comments

All settings specified above doesn’t work for my installation, so I suppose the built-in dbrestore doesn’t work at all for postgres. (Django==1.11.9, django-dbbackup==3.2.0)

But I was able to restore database by psql directly, actually it’s not so hard.

su postgres
psql -d dbname -f ./backup-file.psql

Media restore works ok, so I’m satisfied 😃

+10

zxwild on Feb 10, 2018

still relevant after 3 years…

abdhx on Jan 8, 2021

I solved my issue by removing all the DROP lines, and replacing DROP SCHEMA public by

DROP SCHEMA IF EXISTS public CASCADE

but being able to load dumps in this case would be super cool 😄

MickaelBergem on Dec 1, 2017

Solved this by adding to settings.py:

DBBACKUP_CONNECTORS = {
    'default': {
        'RESTORE_SUFFIX': '--if-exists',
    },
}

sergeydubak on Jan 3, 2024

@ZuluPro I’m kind of confused here, how do I use the new connector? Doesn’t the pip install take everything needed from your branch?

For now, the manual steps I take to restore a dump from another host:

Remove all the lines that drop constraints, indexes, tables.
Just keep the DROP SCHEMA line and append CASCADE at the end.

That’s all folks.

MickaelBergem on Jun 23, 2017

Still relevant for Django 3.2 and Python 3.10

Unfortunetly 'dbbackup.db.postgresql.PgDumpBinaryConnector' did not make any difference.

TheAbhijeet on Feb 11, 2022

The problem with ImportError: No module named postgres Is due to a typo in the connector settings…

'CONNECTOR': 'dbbackup.db.postgres.PgDumpBinaryConnector', should be: 'CONNECTOR': 'dbbackup.db.postgresql.PgDumpBinaryConnector',

@mikeschaekermann

@thimma11 you should just install dbbackup==3.2.0 and then set the connector settings as above, then dbbackup/dbrestore should work.

MaZZly on Dec 27, 2017