dbrestore fails with non-existent relation

[ericswpark]

Bug Report

Describe the bug

Trying to restore from a backup, I'm running into the following error:

Error running:  pg_restore --dbname=postgresql://postgres:password@db:5432/shipper --single-transaction --clean 
pg_restore: error: could not execute query: ERROR:  relation "public.core_statistics" does not exist
Command was: ALTER TABLE ONLY public.core_statistics DROP CONSTRAINT shipper_statistics_build_id_98571750_fk_shipper_build_id;

To Reproduce

1. Back up the database with dbbackup
2. Restore the database with dbrestore

Expected behavior

The backup is restored successfully.

Screenshots or reproduction

The Django project I'm encountering the problem with can be found here: https://github.com/shipperstack/shipper

I am using the Docker Compose of the project which can be found here: https://github.com/shipperstack/shipper-docker

It is possible that some of the DB schema might be a little weird because of all the migrations, but I am pretty confident in asying that 2.x and above have consistent migrations that shouldn't impose a problem on django-dbbackup (but worth keeping in mind).

Versions

Django-dbbackup

• pypi: 4.0.2

External tools

• Python: 3.11.2-r0 (alpine-3.17)
• Django: 4.1.7
• OS: Linux, Docker

[romintomasetti]

I'm also affected by this bug.

Removing --clean makes it work though.

[hkhanna]

Interesting, for me, removing --single-transaction did the trick.

For those who find this, issue, I simply added this to my Django confirm: DBBACKUP_CONNECTORS = {"default": {"SINGLE_TRANSACTION": False}}

[lvieirajr]

Can we add an option on these configurations for postgres to allow us to use the if-exists condition on these drop constraints?
https://www.postgresql.org/docs/current/app-pgrestore.html

[DmytroLitvinov]

+1 for --if-exists

[DmytroLitvinov]

Had an issue with droping constaint which does not exists anymore where I needed --if-exists option.
As a hotfix provided locally next code:

# django-dbbackups
# https://github.com/jazzband/django-dbbackup/issues/478#issuecomment-1677907470
DBBACKUP_CONNECTORS = {'default': {'IF_EXISTS': True}}
DBBACKUP_CONNECTOR_MAPPING = {
    'django.db.backends.postgresql': 'server.apps.core.db.postgresql.PgDumpBinaryConnector',
}

And in the server.apps.core.db.postgresql module next:

from dbbackup.db.postgresql import PgDumpBinaryConnector as CorePgDumpBinaryConnector, create_postgres_uri


class PgDumpBinaryConnector(CorePgDumpBinaryConnector):
    if_exists = False

    def _restore_dump(self, dump):
        dbname = create_postgres_uri(self)
        cmd = f"{self.restore_cmd} {dbname}"

        if self.single_transaction:
            cmd += " --single-transaction"
        if self.drop:
            cmd += " --clean"
        if self.if_exists:
            cmd += " --if-exists"
        cmd = f"{self.restore_prefix} {cmd} {self.restore_suffix}"
        stdout, stderr = self.run_command(cmd, stdin=dump, env=self.restore_env)
        return stdout, stderr

[Archmonger]

PRs to resolve this are welcome!

[DmytroLitvinov]

Hi @Archmonger ,
Created PR for resolving it in the library :)