Merge pull request #14 from dillardblom/rc2

1.0.0-rc.2: disaster recovery fixes

.github/FUNDING.yml

@@ -0,0 +1 @@
+custom: ["https://www.ensembia.com"]

.github/workflows/ci.yml

@@ -104,3 +104,7 @@ jobs:
           persist-credentials: false
       - name: Full restore round trip
         run: tests/integration/full-restore-roundtrip.sh 35-apache
+      - name: Full restore round trip on PostgreSQL, with Mail (foreign keys) and a disabled app
+        run: tests/integration/full-restore-roundtrip.sh 35-apache pgsql
+      - name: Full restore round trip on MariaDB, with Mail (foreign keys) and a disabled app
+        run: tests/integration/full-restore-roundtrip.sh 35-apache mysql

CHANGELOG.md

@@ -9,6 +9,44 @@ instead carried by the app description, the git tag, the release, and this file.
 
 ## [Unreleased]
 
+Fixes from a full disaster recovery test of a production instance (about 1 TB, Nextcloud
+All-in-One onto a plain Nextcloud with PostgreSQL).
+
+### Added
+- `docs/DISASTER-RECOVERY.md`: step-by-step guide for when your server is gone.
+- `occ backup:restore:full --install-apps` installs (from the app store) or enables the apps the
+  old server had enabled, before the restore starts.
+
+### Changed
+- Backups record the structure of every database table. A full restore creates tables that do not
+  exist on the new instance, for example those left behind by an app that was removed long ago or
+  is switched off, instead of stopping at the first one.
+- A full restore no longer refuses when apps are missing: it restores their data and lists the
+  apps to install afterwards. `nextcloud-aio` is never required, so a backup of Nextcloud
+  All-in-One can be restored onto a plain Nextcloud.
+- A full restore onto an installation with a different table prefix (`dbtableprefix`) is refused
+  before it starts, with what to change, instead of restoring into tables nobody uses.
+- All problems are listed at once, with the app each missing table probably belongs to. For
+  backups made before this version, `--skip-missing-tables` leaves out tables whose structure is
+  unknown.
+- A fuller app store description, ready for 1.0.0, and a note on paid restore help by Ensembia.
+- README: switching the server to TCP BBR made backups over a long distance about 3 times faster.
+
+### Fixed
+- A full restore failed on foreign keys (for example those of the Mail app), because tables are
+  restored in name order. Foreign keys are now checked after all rows are loaded, before the
+  restore commits.
+- `occ backup:target:add` without a key pointed to `backup:key:init`, which makes a new key that
+  cannot read existing backups. It now points to `backup:key:import` for a restore, and says that
+  connecting to a location with backups can take a while. While it reads the index of a location
+  with backups, it shows how far it is and about how long it still takes.
+- A restore stopped with "Not found: packs/..." when the location was cleaned up while it ran,
+  for example by the weekly cleanup of the original server during a recovery test on a second
+  server: blobs that were moved into new packs were still looked for in the old ones. A restore
+  now reloads the index and reads them from where they are now.
+- Removing a location left its cached index in the database (tens of thousands of rows for a large
+  backup). It is removed with the location now, and once for locations that are already gone.
+
 ## [1.0.0-rc.1] - 2026-10-17
 
 Release candidate for 1.0.0; the app version is 0.9.7. Only bug fixes until 1.0.0. Tested on a

PLAN.md

@@ -395,6 +395,65 @@ in README "Known limitations":
   3. Snelheid: lezen en uploaden laten overlappen, meerdere bestanden tegelijk lezen, eventueel
      een eigen worker (`occ background-job:worker`). Gemeten op nc01: 55% wachten op de schijf,
      33% op de SMB-upload, ~7% CPU. Vergt extra PHP-processen; botst mogelijk met uitgangspunt 1.
+- **Bevindingen DR-test op PVE02 (2026-10-17, snapshot van nc01, 1 TB, AIO → gewone NC 34 met
+  PostgreSQL 18)** — voor **1.0.0-rc.2**:
+  1. Tabellen van apps die bij de backup **niet aanstonden** (restanten: Deck, ONLYOFFICE,
+     AppAPI, een archief-app) blokkeren de restore met één tabelnaam per poging. Standaard
+     overslaan met één waarschuwing per app; optie om ze toch terug te zetten.
+  2. Alle ontbrekende apps en tabellen **vooraf in één lijst**, per app benoemd (nu één per poging,
+     ook voor uitgeschakelde standaard-apps zoals `admin_audit`).
+  3. `--skip-missing-apps`; `nextcloud-aio` standaard overslaan (bestaat buiten AIO niet), zodat
+     AIO → gewone Nextcloud werkt.
+  4. `--install-apps`: ontbrekende apps uit de app store installeren.
+  5. Apps buiten de app store (eigen builds, `side_menu`, `nextcloud-aio`): documenteren; later
+     eventueel `custom_apps` meenemen in de backup.
+  6. Tabellen van een app die wél aanstond maar die hun tabel later zelf maakt (Memories:
+     `memories_planet_geometry`) netjes afhandelen.
+  7. `backup:target:add` zonder sleutel verwijst naar `key:init`; als er al een repository staat,
+     moet het naar `key:import <kit>` wijzen.
+  8. `backup:target:add` toont geen voortgang bij het ophalen van de index (27.582 bestanden).
+  9. `backup:target:remove` laat de index-cache van die locatie in de database staan; opruimen,
+     ook bestaande wezen.
+  10. Snapshot-meta uitbreiden: ook geïnstalleerde maar uitgeschakelde apps, met per app of hij
+      uit de app store komt; `occ backup:apps <locatie> <snapshot>` toont de lijst leesbaar
+      (geen platte tekst op de locatie: dat lekt welke apps/versies er draaien).
+  11. **Tabelstructuur meedumpen** (kolommen, typen, indexen, primary key), zodat de restore een
+      ontbrekende tabel zelf aanmaakt met de gegevens erin. Lost restanten van oude apps op zonder
+      ze over te slaan; een later opnieuw geïnstalleerde app vindt zijn oude gegevens terug.
+  12. **Foreign keys**: de restore zet tabellen op alfabet terug; `oc_mail_accounts` verwijst naar
+      `oc_mail_mailboxes` en PostgreSQL weigert (fk_61a7e87f59a77cdc). Iedereen met Mail loopt hier
+      vast. Oplossing: in de juiste volgorde terugzetten (afhankelijkheden eerst), of de controle
+      tijdelijk uitzetten en na afloop terugzetten en controleren. In de test: 15 FK's (alle van
+      Mail) tijdelijk verwijderd en na de restore teruggezet: alle 15 geldig op de teruggezette
+      data, dus "uitzetten, terugzetten, achteraf controleren" werkt.
+  13. **SFTP-restore over een lange lijn is traag**: 0,75 MiB/s vanaf Hetzner naar Canada (RTT 122 ms),
+      terwijl OpenSSH `sftp` 16,6 MiB/s haalt. De SFTP-stream van files_external (phpseclib) wacht na
+      elk klein blok op antwoord. Oplossing: pack-ranges bij SFTP met phpseclib's eigen `get()`
+      (veel verzoeken tegelijk) lezen in plaats van via de stream, zoals bij S3. 1 TB duurt nu ~2 weken.
+      Na meten: de grootste oorzaak was het netwerk (cubic, zie 14): met BBR gaat de restore van 0,75
+      naar 2,3 MiB/s, een hele pack lezen 4-5 MiB/s. Meer verzoeken in één stream (DEPTH 16/32) gaf geen
+      duidelijke winst. Verder komen vraagt meerdere verbindingen tegelijk: naar **1.1.0**.
+  14. **Uploaden over een lange lijn**: backup naar OVH S3 Warschau vanaf Canada (RTT 114 ms) haalt
+      ~1 MiB/s met één pack tegelijk; `aws s3 cp` (multipart, parallel) 6 MiB/s. Meerdere packs tegelijk
+      uploaden of S3 multipart. Minder dringend dan 13 (restore).
+      Oorzaak netwerk (met Sysop): pakketverlies trans-Atlantisch + cubic in de VM; met BBR gaat één
+      PUT van 2,4 naar 7,5 MiB/s, ng_backup van ~1 naar ~1,6 MiB/s (rest = serieel lezen/uploaden).
+      Tip over BBR in de README gezet. Let op: PVE02 staat in Canada; een restore in de EU gaat sneller.
+  15. DR-document: in het Docker-voorbeeld "je containernaam" (`docker ps`) i.p.v. `nextcloud`.
+  16. Grote restore (VM 980, snapshot aa7cce8d van de Storage Box) stopte na 22 uur met
+      `Not found: packs/26/2642ef39…`. Oorzaak: de wekelijkse opruiming van nc01 (zo 18-10) heeft
+      dat pakket tijdens de restore omgepakt (blob staat nu in `389567b7…`); de herstelserver had de
+      index van vóór de opruiming. Productie heel: `backup:verify` op nc01 OK (150.639 bestanden,
+      316.830 blobs). Opgelost in rc2: bij een mislukte pakketlezing de index herladen en de blob
+      lezen waar hij nu staat (test `testRestoreFollowsPacksRepackedByAnotherServer`).
+  **Kleine DR-test met rc2 (2026-10-18), volautomatisch geslaagd:** bron VM 981 (NC 34, PostgreSQL,
+  51 GB, Mail met gesynct account, Deck uitgeschakeld, Calendar/Contacts, admin_audit) → OVH S3 →
+  verse VM 982 met alleen de DR-gids en `--install-apps`: apps vanzelf geïnstalleerd, 10 Deck-tabellen
+  aangemaakt, 15 FK's in orde, 23.519/23.519 checksums gelijk, agenda/contact/mail/bord terug.
+  Restore 1 u 47 vanuit Warschau naar Canada (met BBR). Lokaal slaagt de test ook op SQLite en MariaDB.
+  **Daarna verplicht:** een tweede volledige restore op een verse VM, alleen met de HOWTO en de
+  nieuwe opties, zonder handwerk. Pas als die in één keer slaagt: 1.0.0.
+
 - **Later (geen versie):** optie om de sleutel niet op de locatie op te slaan (kit is dan de enige
   kopie; uitdrukkelijke waarschuwing). Primaire object storage en External-storage-koppelingen
   meenemen via de opslaglaag (§3.4; nu niet ondersteund, zie README "Known limitations").

README.md

@@ -9,9 +9,12 @@ ng_backup, and applies to any Nextcloud app that writes to an SMB share.)
 
 **Status: release candidate for 1.0.0 (1.0.0-rc.1, app version 0.9.7).** Tested thoroughly, usable
 alongside your current backup, but not yet a drop-in replacement for it. See "Known limitations" below, `PLAN.md` for the design and
-`docs/HOWTO.md` for a step-by-step guide from setup to a tested restore.
+`docs/HOWTO.md` for a step-by-step guide from setup to a tested restore. Server lost? See
+`docs/DISASTER-RECOVERY.md`.
 
-License: AGPL-3.0-or-later.
+License: AGPL-3.0-or-later. Developed and sponsored by [Ensembia](https://www.ensembia.com).
+Need help restoring a backup after a crash? Ensembia offers paid restore assistance:
+[www.ensembia.com](https://www.ensembia.com).
 
 ## How it works
 
@@ -172,6 +175,13 @@ Contributions welcome via PR — add what you ran into with your own provider.
   the backend being listed is not proof it will work here. Once the extension is present it works
   the same as any other backend; no ng_backup-specific config beyond host/share/user/password.
 
+- **Backups over a long distance (high latency):** on Linux, the default TCP congestion control
+  (cubic) slows a single connection down a lot on a long line with some packet loss. From Canada to
+  an S3 bucket in Warsaw (114 ms), one upload went from 2.4 to 7.5 MiB/s after switching the
+  server (or the VM/container host where TCP ends) to BBR:
+  `sysctl -w net.core.default_qdisc=fq net.ipv4.tcp_congestion_control=bbr`
+  (`modprobe tcp_bbr` first; make it permanent in `/etc/sysctl.d/`).
+
 - **NFS is not a files_external backend at all.** Mount the NFS export on the server yourself
   (e.g. via `/etc/fstab` or a systemd `.mount` unit) and point ng_backup's `local` backend at the
   mount point; ng_backup never mounts or unmounts anything on its own, so an NFS mount dropping

appinfo/info.xml

@@ -3,13 +3,45 @@
     xsi:noNamespaceSchemaLocation="https://apps.nextcloud.com/schema/apps/info.xsd">
     <id>ng_backup</id>
     <name>NG Backup</name>
-    <summary>Encrypted, incremental backups of your Nextcloud with restore from the web interface</summary>
-    <description><![CDATA[Release candidate for 1.0.0: scheduled, encrypted, incremental backups of the database, config and data
-directory to S3, SFTP, WebDAV, FTP, SMB or a local path, with restore of files and folders, of
-single users (via user_migration) and of the whole server onto a fresh installation. Tested
-thoroughly and usable alongside your current backup, but not yet a drop-in replacement for it.
-See the README for known limitations and the recovery kit before relying on it.]]></description>
-    <version>0.9.7</version>
+    <summary>Encrypted, incremental backups of your Nextcloud — files, database and config — with restore from the web interface</summary>
+    <description><![CDATA[Back up your whole Nextcloud — data directory, database and configuration — encrypted and
+incremental, to storage you choose. Restore single files, folders, a user, or the whole server from
+the web interface or `occ`. No shell access or external tools needed, so it also runs on Nextcloud
+All-in-One and hosted Nextcloud.
+
+**Where to**
+- S3 and S3-compatible storage, SFTP, WebDAV, SMB, FTP, Swift or a local path (NFS mount), through
+  the connection code of the External storage app. A location is never mounted and never shows up
+  in Files.
+
+**How**
+- Deduplicated, compressed and encrypted (XChaCha20-Poly1305) on the server before upload, streamed
+  straight to the location: no local copy, no double disk space. Unchanged files are not read again.
+- Database dump through Nextcloud's own connection, in one consistent transaction (PostgreSQL,
+  MySQL/MariaDB, SQLite).
+- Runs in short steps from the background jobs, so a server or container restart does not lose a
+  running backup.
+- Daily schedule, retention policy, and `occ backup:verify` (optionally `--deep`) to check that a
+  backup can be read.
+
+**Safe**
+- Up to three passphrases plus a recovery kit; the passphrase is the actual key.
+- Deletion delay and append-only locations against ransomware or a compromised server; S3 object
+  lock supported.
+- Admin notifications on failures, stale backups and changes to keys and locations.
+
+**Restore**
+- Files and folders into a new folder, merged, or replacing the original — through Nextcloud, so
+  overwritten files keep a version and removed ones go to the trash.
+- One user (account, files, calendars, contacts) via user_migration.
+- The whole server onto a fresh installation (disaster recovery).
+
+Read "Known limitations" in the README before you rely on it, and test a restore. Feedback is very
+welcome: use the "Share your experience" link on the admin page.
+
+Developed and sponsored by [Ensembia](https://www.ensembia.com), which also offers paid help with
+restoring a backup after a crash.]]></description>
+    <version>0.9.8</version>
     <licence>agpl</licence>
     <author mail="dillard.blom@ensembia.com">Dillard Blom</author>
     <namespace>NgBackup</namespace>

docs/DISASTER-RECOVERY.md

@@ -0,0 +1,127 @@
+# Disaster recovery: your server is gone
+
+Your Nextcloud server is lost. You have a new, empty server. These are the steps to get your
+Nextcloud back from an NG Backup location. Do them in this order.
+
+## What you need
+
+- [ ] The **recovery kit** file (`ng_backup-kit.json`) and **one passphrase** of it.
+- [ ] The **connection details of the backup location**: host, user, password or keys, bucket, folder.
+- [ ] A new server with the **same Nextcloud major version** as the old one (for example 34),
+      a database (PostgreSQL, MySQL/MariaDB or SQLite; it may differ from the old one) and room for
+      the whole backup plus a margin.
+- [ ] A list of the apps that are **not in the app store** (your own builds, apps copied in by
+      hand). Keep their packages somewhere safe beforehand.
+
+No kit? If the location still holds its `config` file, the key is there too, but this version
+can only import it from a kit. Keep the kit off the server, next to the passphrase.
+
+## Steps
+
+**1. Install a fresh Nextcloud** of the same major version. Create an admin account. Do not add
+users or files.
+
+**2. Do not let background jobs run yet.** A new Nextcloud runs them on page visits (AJAX).
+Switch that off:
+
+    occ background:cron
+
+As long as no cron is set up, nothing runs. Check that none is:
+
+- Regular server: `sudo crontab -u www-data -l`. If it shows a line with `cron.php`, remove it
+  for now with `sudo crontab -u www-data -e` (put it back in step 9).
+- Docker Compose with a cron service: `docker compose stop cron`.
+- Nextcloud All-in-One: cron runs inside the Nextcloud container; leave it. It does no harm here:
+  the restore keeps NG Backup's own settings of the new server, so it does not start backups.
+
+This keeps the new server quiet (no mail syncs, no notifications, no backups) until it is ready.
+
+**3. Install NG Backup** (the same version or newer) and enable it.
+
+**4. Import the backup key.** Copy the kit to the new server so the web server user can read it.
+
+From your own computer:
+
+    scp ng_backup-kit.json root@newserver:/tmp/
+
+Then on the server, one of:
+
+    chown www-data /tmp/ng_backup-kit.json                                    # regular server
+    docker cp /tmp/ng_backup-kit.json <container>:/tmp/ && \
+      docker exec <container> chown www-data /tmp/ng_backup-kit.json          # Docker
+
+`<container>` is the name of your Nextcloud container: `docker ps` shows it (for example
+`nextcloud-aio-nextcloud`, or `myproject-nextcloud-1` with Docker Compose).
+
+Import it; you type the passphrase yourself:
+
+    occ backup:key:import /tmp/ng_backup-kit.json
+
+It shows the key fingerprint: it must match the one of your old server (on the recovery kit).
+
+**5. Add the backup location** with the same details as before. On a large backup this first reads
+the index and shows how far it is, for example
+`Reading the index: 6,913/26,791 files (25%), about 12 min left`.
+
+    occ backup:target:add offsite sftp -a password::password -o host=... -o user=... -o password=... -o root=... --path=...
+
+If it says "No backup key yet", the key is not imported. Run step 4:
+
+    occ backup:key:import /tmp/ng_backup-kit.json
+
+Do **not** run `backup:key:init`, even though the message suggests it: that makes a brand new key,
+and your backups were encrypted with the old one. NG Backup then refuses the location ("created
+with a different key").
+
+**6. List the restore points** and pick one, normally the newest:
+
+    occ backup:list offsite
+
+**7. Start the restore, and let it install the apps.**
+
+    occ backup:restore:full offsite <snapshot> --install-apps
+
+`--install-apps` first installs every app the old server had enabled from the app store (or
+switches it on, if it is part of Nextcloud). Tables of apps that are missing or were removed long
+ago are created from the backup, so they do not stop the restore.
+
+At the end it lists the apps it could not install, usually your own builds that are not in the
+app store. Copy those into `custom_apps` and enable them (`occ app:enable <app>`); their data is
+already restored.
+
+Backups made before 1.0.0-rc.2 do not record the structure of their tables. If the restore lists
+tables that do not exist here, install the apps they belong to and run it again, or leave them
+out with `--skip-missing-tables`.
+
+**8. Let the restore run.** It restores the database, then the data directory, and takes hours for
+a large backup. If it stops halfway, fix the cause and run the same command again with `--force`.
+
+**9. After the restore.** These worked in our tests:
+
+    occ upgrade
+    occ maintenance:repair
+    occ files:scan --all
+
+- Check `config/config.php`: `trusted_domains`, `overwrite.cli.url` and `overwritehost` come from
+  the old server; change them if the new server has another name. The database settings and the
+  data directory are kept from the new installation.
+- From Nextcloud All-in-One to a regular server: also check the cache settings (`memcache.*`,
+  `redis`), which point at AIO's containers.
+- Log in, open a few files, a calendar and a contact.
+- Start background jobs again (cron), as in step 2 in reverse.
+
+**10. Point your domain at the new server** and check that clients reconnect.
+
+**11. Make a backup of the new server** to the same location (`occ backup:run offsite`). The old
+server must stay off: two servers must never write to the same location.
+
+## Never
+
+- Never let the old server write to the location again if it comes back. Switch its backups off
+  first.
+- Never give your passphrase to anyone. Nobody helping you needs it.
+
+## Help
+
+Stuck? [Ensembia](https://www.ensembia.com), the developer of NG Backup, offers paid help with
+restoring a backup after a crash.

docs/HOWTO.md

@@ -136,6 +136,8 @@ occ backup:user:restore offsite users/<uid>/<exportId> --mode=as-backup
 
 ## 7. Disaster recovery: restore the whole server
 
+Server lost? Follow the step-by-step [DISASTER-RECOVERY.md](DISASTER-RECOVERY.md).
+
 Use a fresh Nextcloud installation of the same major version, with NG Backup installed and
 the same location available. For a test, use a **copy** of the location: two servers writing to one
 location break each other's catalog.
@@ -153,6 +155,10 @@ starts; `--force` skips both (also needed to rerun it after it stopped halfway).
 Afterwards, check that users, files and the database are complete, and run a backup of the restored
 server. The restored installation keeps its own app configuration and secret.
 
+Stuck? [Ensembia](https://www.ensembia.com), the developer of NG Backup, offers paid help with
+restoring a backup after a crash. You keep your passphrase to yourself: it is never needed by
+anyone helping you.
+
 ## 8. Retention
 
 ```

lib/Command/RestoreFull.php

@@ -23,6 +23,7 @@ final class RestoreFull extends Command {
 		private TargetService $targets,
 		private RestoreFullService $restoreFull,
 		private IUserManager $userManager,
+		private \OCP\App\IAppManager $appManager,
 	) {
 		parent::__construct();
 	}
@@ -33,14 +34,19 @@ final class RestoreFull extends Command {
 			->addArgument('target', InputArgument::REQUIRED, 'Location name or id')
 			->addArgument('snapshot', InputArgument::REQUIRED, 'Snapshot id (see backup:list)')
 			->addOption('force', null, InputOption::VALUE_NONE, 'Also on an installation that already has more than one user, and without asking')
+			->addOption('install-apps', null, InputOption::VALUE_NONE, 'First install (from the app store) or enable the apps that were enabled at backup time and are missing here')
+			->addOption('skip-missing-tables', null, InputOption::VALUE_NONE, 'Older backups only: leave out tables that do not exist here and whose structure the backup does not record')
 			->setHelp(<<<'HELP'
 For a FRESH Nextcloud installation only, same major version as the backup, right after
 occ maintenance:install, occ backup:key:import and occ backup:target:add -- before anyone else
 uses this instance.
 
-Every app that was enabled when the snapshot was taken must already be installed here (its
-database tables must exist before the restore can write into them); the command lists what is
-missing and refuses to continue rather than guess.
+Apps: --install-apps first installs (from the app store) or enables every app that was enabled
+when the snapshot was taken. Apps that are not in the app store (own builds) must be copied into
+custom_apps by hand; the command lists what is still missing. Tables of apps that are missing or
+were removed long ago are created from the structure recorded in the backup (backups made with
+1.0.0-rc.2 or later), so they do not block the restore. Older backups do not record it: the
+command then lists those tables per app, and --skip-missing-tables leaves them out.
 
 Steps: the database is replaced (consistent, in one transaction); the data directory is restored
 directly in place; config.php is merged in -- everything from the backup except the database
@@ -75,7 +81,14 @@ HELP);
 		try {
 			$target = $this->targets->get($input->getArgument('target'));
 			$snapshot = (string)$input->getArgument('snapshot');
-			$result = $this->restoreFull->restoreFull($target, $snapshot);
+			$skipMissingTables = (bool)$input->getOption('skip-missing-tables');
+			if ($input->getOption('install-apps')) {
+				$check = $this->restoreFull->checkCompatibility($target, $snapshot, $skipMissingTables);
+				foreach ($check['missingApps'] as $app) {
+					$this->installApp($app, $output);
+				}
+			}
+			$result = $this->restoreFull->restoreFull($target, $snapshot, $skipMissingTables);
 		} catch (\Throwable $e) {
 			$output->writeln('<error>' . $e->getMessage() . '</error>');
 			$output->writeln('If this happened after the restore had started, the instance may be partly restored: fix the cause and run the same command again with --force.');
@@ -88,10 +101,46 @@ HELP);
 			$result['configKeys'],
 			$result['dataFiles'],
 		));
+		if ($result['dbReport']['created'] !== []) {
+			$output->writeln(sprintf('Created <info>%d</info> tables that did not exist here (apps that are missing or were removed): %s',
+				count($result['dbReport']['created']), implode(', ', $result['dbReport']['created'])));
+		}
+		foreach ($result['dbReport']['foreignKeyErrors'] ?? [] as $error) {
+			$output->writeln('<comment>Could not add a foreign key to a created table (the data is restored): ' . $error . '</comment>');
+		}
+		if ($result['dbReport']['missing'] !== []) {
+			$output->writeln('<comment>Left out (structure unknown): ' . implode(', ', $result['dbReport']['missing']) . '</comment>');
+		}
+		if ($result['missingApps'] !== []) {
+			$output->writeln('<comment>These apps were enabled on the old server but are not installed here. Their data is restored; install them so they work again:</comment>');
+			foreach ($result['missingApps'] as $app) {
+				$output->writeln("  occ app:install $app   (not in the app store? copy it into custom_apps and run occ app:enable $app)");
+			}
+		}
 		if (!$result['dbConsistent']) {
 			$output->writeln('<comment>Warning: this snapshot\'s database dump was made over several steps (web cron), so it is not one consistent point in time. Check the instance carefully; prefer a snapshot made with system cron.</comment>');
 		}
 		$output->writeln('Next: check trusted_domains and overwritehost/overwriteprotocol match this server, then occ maintenance:repair.');
 		return 0;
 	}
+
+	/** Enable an app that is here but switched off, or install it from the app store. */
+	private function installApp(string $app, OutputInterface $output): void {
+		try {
+			$this->appManager->getAppPath($app);
+			$command = 'app:enable'; // here, but switched off
+		} catch (\OCP\App\AppPathNotFoundException) {
+			$command = 'app:install';
+		}
+		$output->writeln("Running occ $command $app ...");
+		try {
+			$code = $this->getApplication()?->find($command)->run(new \Symfony\Component\Console\Input\ArrayInput(['app-id' => $command === 'app:enable' ? [$app] : $app]), $output);
+		} catch (\Throwable $e) {
+			$code = 1;
+			$output->writeln('<comment>' . $e->getMessage() . '</comment>');
+		}
+		if ($code !== 0) {
+			$output->writeln("<comment>Could not $command $app (not in the app store?). Copy it into custom_apps and enable it, or restore without it.</comment>");
+		}
+	}
 }

lib/Command/TargetAdd.php

@@ -44,7 +44,10 @@ HELP);
 
 	protected function execute(InputInterface $input, OutputInterface $output): int {
 		if (!$this->keys->isInitialized()) {
-			$output->writeln('<error>No backup key yet: run occ backup:key:init first.</error>');
+			$output->writeln('<error>No backup key yet.</error>');
+			$output->writeln('Restoring from a location that already has backups (disaster recovery)? Import the key from the recovery kit first:');
+			$output->writeln('  occ backup:key:import /path/to/ng_backup-kit.json');
+			$output->writeln('Only for a new location without backups: create a new key with occ backup:key:init. A new key cannot read existing backups.');
 			return 1;
 		}
 		$options = [];
@@ -60,9 +63,16 @@ HELP);
 			$output->writeln('<error>--auth is required (see occ backup:target:backends)</error>');
 			return 1;
 		}
+		// Adopting an existing repository reads its whole index first, which takes a while on a
+		// large backup or a slow line; show how far it is instead of looking stuck.
+		$output->writeln('Connecting to the location; with existing backups this reads their index first ...');
 		try {
-			$r = $this->targets->add($input->getArgument('name'), $input->getArgument('backend'), $input->getOption('auth'), $options, (string)$input->getOption('path'));
+			$r = $this->targets->add($input->getArgument('name'), $input->getArgument('backend'), $input->getOption('auth'), $options,
+				(string)$input->getOption('path'), self::progress($output));
 		} catch (\Throwable $e) {
+			if ($output->isDecorated()) {
+				$output->write("\r\033[K"); // clear an unfinished progress line
+			}
 			$output->writeln('<error>' . $e->getMessage() . '</error>');
 			return 1;
 		}
@@ -70,4 +80,34 @@ HELP);
 			$r['target']->getRepositoryId(), $r['created'] ? 'created' : 'found and adopted'));
 		return 0;
 	}
+
+	/**
+	 * Progress of reading the index: on a terminal one line that is updated in place, otherwise
+	 * (a log, a pipe) a line every 30 seconds. The time left is estimated from the rate so far.
+	 *
+	 * @return callable(int, int): void
+	 */
+	private static function progress(OutputInterface $output): callable {
+		$start = microtime(true);
+		$shown = 0.0;
+		$inPlace = $output->isDecorated();
+		return static function (int $done, int $total) use ($output, $start, &$shown, $inPlace): void {
+			$now = microtime(true);
+			if ($done < $total && $now - $shown < ($inPlace ? 1 : 30)) {
+				return;
+			}
+			$shown = $now;
+			$line = sprintf('Reading the index: %s/%s files (%d%%)', number_format($done), number_format($total), intdiv(100 * $done, max(1, $total)));
+			$elapsed = $now - $start;
+			if ($done < $total && $done > 0 && $elapsed >= 5) {
+				$left = (int)ceil($elapsed / (float)$done * (float)($total - $done) / 60.0);
+				$line .= $left <= 1 ? ', less than a minute left' : sprintf(', about %d min left', $left);
+			}
+			if ($inPlace) {
+				$output->write("\r\033[K" . $line . ($done >= $total ? "\n" : ''));
+			} else {
+				$output->writeln($line);
+			}
+		};
+	}
 }

lib/Db/DbDumper.php

@@ -23,8 +23,12 @@ use OCA\NgBackup\Repository\Repository;
  *   sets, so a single big SELECT would not stream).
  * - Each table becomes its own blob stream of JSON lines: a header line, then one JSON array per
  *   row. A table that did not change produces the same blobs and costs nothing in the next run.
- * - The schema itself is not dumped: it comes from Nextcloud's migrations on the instance that is
- *   restored into (same Nextcloud and app versions). The dump records those versions.
+ * - The structure of each table (columns, types, primary key, indexes) is recorded in the manifest,
+ *   so a restore can create a table that does not exist on the new instance, for example one left
+ *   behind by an app that was removed long ago. Tables that exist keep the structure the new
+ *   instance's migrations gave them.
+ * - Foreign keys are not checked while rows are loaded (tables are restored in name order, not in
+ *   dependency order), and are checked again before the restore commits.
  *
  * Phase 0 uses the Doctrine connection behind IDBConnection (private API) for schema
  * introspection; to be replaced by information_schema queries or a public API.
@@ -108,7 +112,7 @@ final class DbDumper {
 						break;
 					}
 					$state['result'][$table] = ['blobs' => array_merge(...$state['segments']), 'rows' => $state['rows'],
-						'bytes' => $state['bytes'], 'sha256' => hash_final($hash)];
+						'bytes' => $state['bytes'], 'sha256' => hash_final($hash), 'schema' => self::structure($schema)];
 					$state = array_merge($state, ['i' => $state['i'] + 1, 'after' => null, 'segments' => [], 'rows' => 0, 'bytes' => 0, 'hash' => null]);
 					if (microtime(true) >= $deadline && $state['i'] < count($state['tables'])) {
 						break;
@@ -137,18 +141,38 @@ final class DbDumper {
 	 * Replace the contents of every table in the dump. Tables that exist but are not in the dump
 	 * are left alone (e.g. a newer app); the caller decides whether that is acceptable.
 	 *
-	 * @param array{tables: array<string, array{blobs: list<string>, rows: int}>} $manifest
+	 * @param array{tables: array<string, array{blobs: list<string>, rows: int, sha256: string, schema?: array}>, sequences?: array} $manifest
 	 */
-	public function restore(Repository $repo, array $manifest, ?array &$report = null, ?callable $heartbeat = null): int {
-		$sm = $this->db->createSchemaManager();
-		$existing = array_flip($sm->listTableNames());
+	public function restore(Repository $repo, array $manifest, ?array &$report = null, ?callable $heartbeat = null, bool $skipMissing = false): int {
+		$report = ['skipped' => [], 'restored' => [], 'created' => [], 'missing' => []];
+		$source = self::dumpPrefix($manifest);
+		if ($source !== null && $source !== $this->prefix) {
+			// Every table would look missing and be created under the old prefix, unused.
+			throw new \RuntimeException("The backup's tables use the prefix '$source', this installation '{$this->prefix}'. Install Nextcloud again with 'dbtableprefix' => '$source' in config/config.php before occ maintenance:install, and restore again.");
+		}
+		$missing = $this->missingTables($manifest);
+		$unknown = array_values(array_filter($missing, fn (string $t) => !isset($manifest['tables'][$t]['schema'])));
+		if ($unknown !== [] && !$skipMissing) {
+			throw new \RuntimeException(self::describeMissing($unknown, $this->prefix));
+		}
+		// Tables the backup knows the structure of are created first (DDL is not transactional
+		// everywhere); tables it does not know are left out, as asked.
+		foreach ($missing as $table) {
+			if (isset($manifest['tables'][$table]['schema'])) {
+				$this->db->createSchemaManager()->createTable(self::tableFromStructure($table, $manifest['tables'][$table]['schema']));
+				$report['created'][] = $table;
+			} else {
+				$report['missing'][] = $table;
+			}
+		}
 		$total = 0;
-		$report = ['skipped' => [], 'restored' => []];
+		$foreignKeys = [];
 		$this->db->beginTransaction();
 		try {
+			$foreignKeys = $this->suspendForeignKeys();
 			foreach ($manifest['tables'] as $table => $info) {
-				if (!isset($existing[$table])) {
-					throw new \RuntimeException("Table $table from the backup does not exist here (different app versions?)");
+				if (in_array($table, $report['missing'], true)) {
+					continue;
 				}
 				// Unchanged since the backup: leave it alone (much faster than delete + insert).
 				$live = $this->checksum($table);
@@ -193,14 +217,204 @@ final class DbDumper {
 				$report['restored'][] = $table;
 			}
 			$this->restoreSequences($manifest['sequences'] ?? []);
+			$this->resumeForeignKeys($foreignKeys);
 			$this->db->commit();
+			// Foreign keys of the tables created above, now their rows are in. Not inside the
+			// transaction: MySQL commits on DDL. A failure is reported, not fatal: the data is
+			// restored either way.
+			foreach ($report['created'] as $table) {
+				$structure = $manifest['tables'][$table]['schema'] ?? [];
+				foreach ($structure['foreignKeys'] ?? [] as $fk) {
+					try {
+						$this->db->createSchemaManager()->createForeignKey(
+							new \Doctrine\DBAL\Schema\ForeignKeyConstraint($fk['columns'], $fk['table'], $fk['foreign'], $fk['name'], $fk['options'] ?? []),
+							$table);
+					} catch (\Throwable $e) {
+						$report['foreignKeyErrors'][] = $table . '.' . $fk['name'] . ': ' . $e->getMessage();
+					}
+				}
+			}
 		} catch (\Throwable $e) {
 			$this->db->rollBack();
+			// PostgreSQL rolls the dropped foreign keys back with the transaction; MySQL's session
+			// switch must be turned on again by hand.
+			if (in_array('SET FOREIGN_KEY_CHECKS = 1', $foreignKeys, true)) {
+				$this->db->executeStatement('SET FOREIGN_KEY_CHECKS = 1');
+			}
 			throw $e;
 		}
 		return $total;
 	}
 
+	/**
+	 * The table prefix of the instance the dump was made on (from its appconfig table), or null
+	 * when the dump has none.
+	 *
+	 */
+	public static function dumpPrefix(array $manifest): ?string {
+		/** @var list<string> $tables table names */
+		$tables = array_keys($manifest['tables'] ?? []);
+		foreach ($tables as $name) {
+			if (str_ends_with($name, 'appconfig') && !str_ends_with($name, '_ex_appconfig')) {
+				return substr($name, 0, -strlen('appconfig'));
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Tables in the dump that do not exist on this instance.
+	 *
+	 * @return list<string>
+	 */
+	public function missingTables(array $manifest): array {
+		$existing = array_flip($this->db->createSchemaManager()->listTableNames());
+		return array_values(array_filter(array_keys($manifest['tables']), fn (string $t) => !isset($existing[$t])));
+	}
+
+	/** One message for all missing tables of an older backup, grouped by the app they probably belong to. */
+	public static function describeMissing(array $tables, string $prefix): string {
+		$groups = [];
+		foreach ($tables as $t) {
+			$name = substr($t, strlen($prefix));
+			$groups[explode('_', $name, 2)[0]][] = $t;
+		}
+		$lines = [];
+		foreach ($groups as $app => $list) {
+			$lines[] = '- ' . $app . ': ' . implode(', ', $list);
+		}
+		return "These tables from the backup do not exist here, and this backup does not record their structure (made before 1.0.0-rc.2):\n"
+			. implode("\n", $lines)
+			. "\nInstall the apps they belong to (often apps that were removed or switched off long ago) and run the restore again, or leave these tables out with --skip-missing-tables.";
+	}
+
+	/**
+	 * Portable description of a table: enough to create it again, also on another database type.
+	 *
+	 * @return array{columns: list<array<string, mixed>>, pk: list<string>, indexes: list<array{name: string, columns: list<string>, unique: bool}>}
+	 */
+	private static function structure(\Doctrine\DBAL\Schema\Table $table): array {
+		$columns = [];
+		foreach ($table->getColumns() as $c) {
+			$columns[] = ['name' => $c->getName(), 'type' => \Doctrine\DBAL\Types\Type::lookupName($c->getType()),
+				'length' => $c->getLength(), 'precision' => $c->getPrecision(), 'scale' => $c->getScale(),
+				'unsigned' => $c->getUnsigned(), 'fixed' => $c->getFixed(), 'notnull' => $c->getNotnull(),
+				'default' => $c->getDefault(), 'autoincrement' => $c->getAutoincrement()];
+		}
+		$indexes = [];
+		foreach ($table->getIndexes() as $i) {
+			if (!$i->isPrimary()) {
+				// options holds the prefix lengths MySQL needs for indexes on long text columns
+				$indexes[] = ['name' => $i->getName(), 'columns' => array_values($i->getColumns()), 'unique' => $i->isUnique(),
+					'flags' => array_values($i->getFlags()), 'options' => $i->getOptions()];
+			}
+		}
+		$foreignKeys = [];
+		foreach ($table->getForeignKeys() as $fk) {
+			$foreignKeys[] = ['name' => $fk->getName(), 'columns' => array_values($fk->getLocalColumns()),
+				'table' => $fk->getForeignTableName(), 'foreign' => array_values($fk->getForeignColumns()), 'options' => $fk->getOptions()];
+		}
+		return ['columns' => $columns, 'pk' => array_values($table->getPrimaryKey()?->getColumns() ?? []), 'indexes' => $indexes,
+			'foreignKeys' => $foreignKeys];
+	}
+
+	private static function tableFromStructure(string $name, array $structure): \Doctrine\DBAL\Schema\Table {
+		$table = new \Doctrine\DBAL\Schema\Table($name);
+		foreach ($structure['columns'] as $c) {
+			$table->addColumn($c['name'], $c['type'], array_filter([
+				'length' => $c['length'], 'precision' => $c['precision'], 'scale' => $c['scale'],
+				'unsigned' => $c['unsigned'], 'fixed' => $c['fixed'], 'notnull' => $c['notnull'],
+				'default' => $c['default'], 'autoincrement' => $c['autoincrement'],
+			], fn ($v) => $v !== null));
+		}
+		if ($structure['pk'] !== []) {
+			$table->setPrimaryKey($structure['pk']);
+		}
+		foreach ($structure['indexes'] as $i) {
+			$i['unique']
+				? $table->addUniqueIndex($i['columns'], $i['name'], $i['options'] ?? [])
+				: $table->addIndex($i['columns'], $i['name'], $i['flags'] ?? [], $i['options'] ?? []);
+		}
+		return $table;
+	}
+
+	/**
+	 * Stop checking foreign keys while rows are loaded in name order. PostgreSQL has no session
+	 * switch for this without superuser rights, so its foreign keys of Nextcloud tables are dropped
+	 * here and added back (and so checked) by resumeForeignKeys(), inside the same transaction.
+	 *
+	 * @return list<string> statements that restore the foreign keys
+	 */
+	private function suspendForeignKeys(): array {
+		$platform = $this->db->getDatabasePlatform();
+		if ($platform instanceof \Doctrine\DBAL\Platforms\PostgreSQLPlatform) {
+			$rows = $this->db->fetchAllAssociative(
+				"SELECT conrelid::regclass::text AS tbl, conname, pg_get_constraintdef(oid) AS def
+				 FROM pg_constraint WHERE contype = 'f' AND connamespace = current_schema()::regnamespace");
+			$restore = [];
+			foreach ($rows as $r) {
+				if (!str_starts_with(trim($r['tbl'], '"'), $this->prefix)) {
+					continue;
+				}
+				$this->db->executeStatement(sprintf('ALTER TABLE %s DROP CONSTRAINT %s', $r['tbl'], $this->db->quoteIdentifier($r['conname'])));
+				$restore[] = sprintf('ALTER TABLE %s ADD CONSTRAINT %s %s', $r['tbl'], $this->db->quoteIdentifier($r['conname']), $r['def']);
+			}
+			return $restore;
+		}
+		if ($platform instanceof \Doctrine\DBAL\Platforms\AbstractMySQLPlatform) {
+			// MySQL does not check rows again when FOREIGN_KEY_CHECKS goes back to 1, and its DDL
+			// would commit the transaction halfway. So every foreign key is checked explicitly,
+			// with a query that finds rows pointing at nothing (resumeForeignKeys()).
+			$rows = $this->db->fetchAllAssociative(
+				'SELECT TABLE_NAME AS tbl, CONSTRAINT_NAME AS name, COLUMN_NAME AS col, REFERENCED_TABLE_NAME AS rtbl, REFERENCED_COLUMN_NAME AS rcol
+				 FROM information_schema.KEY_COLUMN_USAGE
+				 WHERE TABLE_SCHEMA = DATABASE() AND REFERENCED_TABLE_NAME IS NOT NULL
+				 ORDER BY TABLE_NAME, CONSTRAINT_NAME, ORDINAL_POSITION');
+			$keys = [];
+			foreach ($rows as $r) {
+				if (str_starts_with((string)$r['tbl'], $this->prefix)) {
+					$keys[$r['tbl'] . "\0" . $r['name']][] = $r;
+				}
+			}
+			$q = fn (string $i): string => $this->db->quoteIdentifier($i);
+			$checks = ['SET FOREIGN_KEY_CHECKS = 1'];
+			foreach ($keys as $parts) {
+				$join = implode(' AND ', array_map(fn (array $r): string => 'c.' . $q($r['col']) . ' = p.' . $q($r['rcol']), $parts));
+				$set = implode(' AND ', array_map(fn (array $r): string => 'c.' . $q($r['col']) . ' IS NOT NULL', $parts));
+				$checks[] = sprintf('SELECT COUNT(*) FROM %s c LEFT JOIN %s p ON %s WHERE %s AND p.%s IS NULL /* %s */',
+					$q($parts[0]['tbl']), $q($parts[0]['rtbl']), $join, $set, $q($parts[0]['rcol']), $parts[0]['name']);
+			}
+			$this->db->executeStatement('SET FOREIGN_KEY_CHECKS = 0');
+			return $checks;
+		}
+		if ($platform instanceof \Doctrine\DBAL\Platforms\SqlitePlatform) {
+			$this->db->executeStatement('PRAGMA defer_foreign_keys = ON'); // checked at commit
+		}
+		return [];
+	}
+
+	/**
+	 * Check the foreign keys again; a row that breaks one fails the restore here, before it commits.
+	 * Statements add them back (PostgreSQL) or switch the checks on (MySQL); queries count the rows
+	 * that point at nothing (MySQL) and must find none.
+	 */
+	private function resumeForeignKeys(array $statements): void {
+		foreach ($statements as $sql) {
+			try {
+				if (str_starts_with($sql, 'SELECT ')) {
+					$orphans = (int)$this->db->fetchOne($sql);
+					if ($orphans > 0) {
+						throw new \RuntimeException("$orphans rows point at nothing");
+					}
+				} else {
+					$this->db->executeStatement($sql);
+				}
+			} catch (\Throwable $e) {
+				throw new \RuntimeException('The restored data breaks a foreign key (' . $sql . '): ' . $e->getMessage(), 0, $e);
+			}
+		}
+	}
+
 	/** Same checksum as dump(): sha256 over the row lines in primary-key order. */
 	public function checksum(string $table): array {
 		$hash = hash_init('sha256');

lib/Db/DbIndexCache.php

@@ -64,6 +64,13 @@ final class DbIndexCache implements IIndexCache {
 		}
 	}
 
+	/** Drop the cached index of a repository that no location uses any more. */
+	public function forget(string $repositoryId): void {
+		$qb = $this->db->getQueryBuilder();
+		$qb->delete('ngb_index')->where($qb->expr()->eq('repository_id', $qb->createNamedParameter($repositoryId)));
+		$qb->executeStatement();
+	}
+
 	/** All or nothing: when it fails, the cache stays as it was. */
 	public function replaceAll(string $repositoryId, array $packs): void {
 		$this->transaction(function () use ($repositoryId, $packs): void {

lib/Migration/Version000006Date20261018000000.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Migration;
+
+use Closure;
+use OCP\IDBConnection;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+/**
+ * Removing a location left the cached index of its repository behind (tens of thousands of rows
+ * for a large backup). Drop the cache of repositories no location uses any more.
+ */
+final class Version000006Date20261018000000 extends SimpleMigrationStep {
+	public function __construct(
+		private IDBConnection $db,
+	) {
+	}
+
+	public function postSchemaChange(IOutput $output, Closure $schemaClosure, array $options): void {
+		$used = $this->db->getQueryBuilder();
+		$used->select('repository_id')->from('ngb_targets')->where($used->expr()->isNotNull('repository_id'));
+		$keep = array_column($used->executeQuery()->fetchAll(), 'repository_id');
+		$delete = $this->db->getQueryBuilder();
+		$delete->delete('ngb_index');
+		if ($keep !== []) {
+			$delete->where($delete->expr()->notIn('repository_id', $delete->createNamedParameter($keep, \OCP\DB\QueryBuilder\IQueryBuilder::PARAM_STR_ARRAY)));
+		}
+		$removed = $delete->executeStatement();
+		if ($removed > 0) {
+			$output->info("Removed $removed cached index rows of locations that no longer exist");
+		}
+	}
+}

lib/Repository/Repository.php

@@ -81,7 +81,8 @@ final class Repository {
 	}
 
 	/** Open with the master key the server holds (scheduled backups, no passphrase needed). */
-	public static function openWithKey(IBackend $backend, KeyRing $keys, ?IIndexCache $cache = null, ?ICatalogAnchor $anchor = null): self {
+	/** @param ?callable(int, int): void $progress index files downloaded so far, and in all (see BlobIndex::load()) */
+	public static function openWithKey(IBackend $backend, KeyRing $keys, ?IIndexCache $cache = null, ?ICatalogAnchor $anchor = null, ?callable $progress = null): self {
 		$config = self::readConfig($backend);
 		try {
 			$ok = isset($config['check']) && (new StreamCipher($keys))->decryptString((string)base64_decode($config['check'], true), 'config-check') === $config['id'];
@@ -95,7 +96,7 @@ final class Repository {
 		if ($cache !== null) {
 			$repo->index->setCache($cache, $config['id']);
 		}
-		$repo->index->load();
+		$repo->index->load(false, $progress);
 		$repo->loadCatalog($anchor);
 		return $repo;
 	}
@@ -771,16 +772,48 @@ final class Repository {
 			$ranges[] = [$curPath, $curOffset, $curLength];
 			$parts[] = $curParts;
 		}
-		foreach ($this->backend->getRanges($ranges) as $i => $data) {
-			foreach ($parts[$i] as [$id, $at, $length]) {
-				yield $this->decodeBlob($id, substr($data, $at, $length));
+		$done = 0;
+		try {
+			foreach ($this->backend->getRanges($ranges) as $i => $data) {
+				foreach ($parts[$i] as [$id, $at, $length]) {
+					yield $this->decodeBlob($id, substr($data, $at, $length));
+					$done++;
+				}
+			}
+		} catch (BackendException $e) {
+			// A pack moved (see loadBlob()): the rest one blob at a time, from the fresh index.
+			$this->refreshIndex($e);
+			foreach (array_slice($ids, $done) as $id) {
+				yield $this->loadBlob($id);
 			}
 		}
 	}
 
 	private function loadBlob(string $id): string {
 		[$pack, $offset, $length] = $this->index->get($id);
-		return $this->decodeBlob($id, $this->packReader->read($pack, $offset, $length));
+		try {
+			$encrypted = $this->packReader->read($pack, $offset, $length);
+		} catch (BackendException $e) {
+			// Another server's cleanup may have repacked this blob into a new pack since the index
+			// was loaded (a disaster recovery test while the original server still runs). Reload
+			// the index from the location; read again only if the blob has moved.
+			$this->refreshIndex($e);
+			[$moved, $offset, $length] = $this->index->get($id);
+			if ($moved === $pack) {
+				throw $e;
+			}
+			$encrypted = $this->packReader->read($moved, $offset, $length);
+		}
+		return $this->decodeBlob($id, $encrypted);
+	}
+
+	/** Reload the index from the location after a failed pack read; rethrows that failure if it cannot. */
+	private function refreshIndex(BackendException $cause): void {
+		try {
+			$this->index->load();
+		} catch (\Throwable) {
+			throw $cause;
+		}
 	}
 
 	/** Decrypts and checks a blob read from its pack; throws when it is corrupted or tampered with. */

lib/Service/RestoreFullService.php

@@ -43,34 +43,55 @@ final class RestoreFullService {
 	) {
 	}
 
+	/** Apps that only exist in a particular setup and are never needed elsewhere. */
+	private const ENVIRONMENT_APPS = ['nextcloud-aio'];
+
 	/**
-	 * Whether this installation can receive $snapshotId: same Nextcloud major version, and every
-	 * app that was enabled at backup time already installed here (its tables must exist before
-	 * the database restore can write into them).
+	 * Whether this installation can receive $snapshotId, all problems at once:
+	 * - the same Nextcloud major version is required;
+	 * - apps that were enabled at backup time but are not here (they work again once installed);
+	 * - tables in the backup that do not exist here: a backup made from 1.0.0-rc.2 on records
+	 *   their structure and the restore creates them, an older one cannot (missingTables).
 	 *
-	 * @return array{ok:bool, currentMajor:string, snapshotMajor:string, missingApps:list<string>}
+	 * @return array{ok:bool, currentMajor:string, snapshotMajor:string, missingApps:list<string>, missingTables:list<string>}
 	 */
-	public function checkCompatibility(Target $target, string $snapshotId): array {
-		$meta = $this->targets->repository($target)->snapshotMeta($snapshotId);
+	public function checkCompatibility(Target $target, string $snapshotId, bool $skipMissingTables = false): array {
+		$repo = $this->targets->repository($target);
+		$meta = $repo->snapshotMeta($snapshotId);
 		$currentMajor = explode('.', $this->config->getSystemValueString('version'))[0];
 		$snapshotMajor = explode('.', (string)($meta['nextcloud'] ?? ''))[0];
 		$enabled = array_flip($this->appManager->getEnabledApps());
-		$missingApps = array_values(array_diff(array_keys($meta['apps'] ?? []), array_keys($enabled)));
+		$missingApps = array_values(array_diff(array_keys($meta['apps'] ?? []), array_keys($enabled), self::ENVIRONMENT_APPS));
+		$missingTables = [];
+		$prefixMismatch = null;
+		if (isset($meta['db'])) {
+			$manifest = json_decode($repo->getObject($meta['db']), true, 512, JSON_THROW_ON_ERROR);
+			$prefix = $this->config->getSystemValueString('dbtableprefix', 'oc_');
+			$sourcePrefix = DbDumper::dumpPrefix($manifest);
+			if ($sourcePrefix !== null && $sourcePrefix !== $prefix) {
+				$prefixMismatch = [$sourcePrefix, $prefix];
+			}
+			$dumper = new DbDumper($this->db->getInner(), $prefix);
+			$missingTables = array_values(array_filter($dumper->missingTables($manifest),
+				fn (string $t) => !isset($manifest['tables'][$t]['schema']) && !str_starts_with($t, $prefix . 'ngb_')));
+		}
 		return [
-			'ok' => $currentMajor === $snapshotMajor && $missingApps === [],
+			'ok' => $currentMajor === $snapshotMajor && $prefixMismatch === null && ($missingTables === [] || $skipMissingTables),
 			'currentMajor' => $currentMajor,
 			'snapshotMajor' => $snapshotMajor,
 			'missingApps' => $missingApps,
+			'missingTables' => $prefixMismatch === null ? $missingTables : [],
+			'prefixMismatch' => $prefixMismatch,
 		];
 	}
 
-	/** @return array{dbReport:array, dataFiles:int, configKeys:int, dbConsistent:bool} */
-	public function restoreFull(Target $target, string $snapshotId): array {
-		$check = $this->checkCompatibility($target, $snapshotId);
+	/** @return array{dbReport:array, dataFiles:int, configKeys:int, dbConsistent:bool, missingApps:list<string>} */
+	public function restoreFull(Target $target, string $snapshotId, bool $skipMissingTables = false): array {
+		$check = $this->checkCompatibility($target, $snapshotId, $skipMissingTables);
 		if (!$check['ok']) {
 			throw new \RuntimeException($this->describeBlockers($check));
 		}
-		return $this->withSharedLock($target, function (callable $refresh) use ($target, $snapshotId) {
+		return $this->withSharedLock($target, function (callable $refresh) use ($target, $snapshotId, $skipMissingTables, $check) {
 			$beat = LeaseService::throttled($refresh);
 			$repo = $this->targets->repository($target);
 			$meta = $repo->snapshotMeta($snapshotId);
@@ -102,7 +123,7 @@ final class RestoreFullService {
 				$ownAppConfig = $this->preserveOwnAppConfig();
 				$dumper = new DbDumper($this->db->getInner(), $prefix);
 				try {
-					$dumper->restore($repo, $manifest, $dbReport, $beat);
+					$dumper->restore($repo, $manifest, $dbReport, $beat, $skipMissingTables);
 				} finally {
 					$this->restoreOwnAppConfig($ownAppConfig);
 				}
@@ -125,8 +146,8 @@ final class RestoreFullService {
 				);
 			}
 
-			return ['dbReport' => $dbReport ?? ['skipped' => [], 'restored' => []], 'dataFiles' => $dataFiles, 'configKeys' => count($backupConfig),
-				'dbConsistent' => (bool)($manifest['consistent'] ?? true)];
+			return ['dbReport' => $dbReport ?? ['skipped' => [], 'restored' => [], 'created' => [], 'missing' => []], 'dataFiles' => $dataFiles, 'configKeys' => count($backupConfig),
+				'dbConsistent' => (bool)($manifest['consistent'] ?? true), 'missingApps' => $check['missingApps']];
 		});
 	}
 
@@ -209,11 +230,15 @@ final class RestoreFullService {
 		if ($check['currentMajor'] !== $check['snapshotMajor']) {
 			$parts[] = "this installation is Nextcloud {$check['currentMajor']}, the backup is from {$check['snapshotMajor']} (same major version required)";
 		}
-		if ($check['missingApps'] !== []) {
-			$parts[] = 'install these apps first (their tables must exist before the database restore can use them): '
-				. implode(', ', array_map(fn (string $a) => "occ app:install $a", $check['missingApps']));
+		if (($check['prefixMismatch'] ?? null) !== null) {
+			[$source, $here] = $check['prefixMismatch'];
+			$parts[] = "the backup's tables use the prefix '$source', this installation '$here': install Nextcloud again with 'dbtableprefix' => '$source' in config/config.php before occ maintenance:install, and restore again";
 		}
-		return implode('; ', $parts);
+		if ($check['missingTables'] !== []) {
+			$prefix = $this->config->getSystemValueString('dbtableprefix', 'oc_');
+			$parts[] = DbDumper::describeMissing($check['missingTables'], $prefix);
+		}
+		return implode("\n", $parts);
 	}
 
 	private function withSharedLock(Target $target, callable $fn): mixed {

lib/Service/TargetService.php

@@ -48,15 +48,16 @@ final class TargetService {
 	 * installation's key), then save it.
 	 *
 	 * @param array<string, mixed> $options
+	 * @param ?callable(int, int): void $progress reading an existing repository's index: files done, and in all
 	 * @return array{target: Target, created: bool}
 	 */
-	public function add(string $name, string $backend, string $auth, array $options, string $basePath): array {
+	public function add(string $name, string $backend, string $auth, array $options, string $basePath, ?callable $progress = null): array {
 		$this->validateName($name);
 		$this->requireUsableBackend($backend);
 		$keys = $this->keys->keyRing();
 		$storageBackend = $this->buildBackend($backend, $auth, $options, $basePath);
 		if ($storageBackend->exists('config')) {
-			$repo = Repository::openWithKey($storageBackend, $keys, $this->indexCache, $this->anchor);
+			$repo = Repository::openWithKey($storageBackend, $keys, $this->indexCache, $this->anchor, $progress);
 			$created = false;
 		} else {
 			$repo = Repository::initWithKey($storageBackend, $keys, $this->keys->wrappedKey(), $this->anchor);
@@ -259,6 +260,11 @@ final class TargetService {
 	/** Remove the target from NG Backup. The backups on the target itself are not touched. */
 	public function remove(Target $target): void {
 		$this->mapper->delete($target);
+		// The cached index of its repository is only of use while a location points at it
+		$repositoryId = $target->getRepositoryId();
+		if ($repositoryId !== null && !array_filter($this->list(), fn (Target $t) => $t->getRepositoryId() === $repositoryId)) {
+			$this->indexCache->forget($repositoryId);
+		}
 	}
 
 	public function backend(Target $target): IBackend {

psalm-baseline.xml

@@ -153,10 +153,6 @@
     </PossiblyFalseArgument>
   </file>
   <file src="lib/Db/DbDumper.php">
-    <InvalidArrayOffset>
-      <code><![CDATA[$info['sha256']]]></code>
-      <code><![CDATA[$manifest['sequences']]]></code>
-    </InvalidArrayOffset>
     <MissingClosureReturnType>
       <code><![CDATA[fn ($c) => $end[array_search($c, $columns, true)]]]></code>
       <code><![CDATA[fn ($c) => $q($c)]]></code>
@@ -189,6 +185,12 @@
       <code><![CDATA[$this->db]]></code>
       <code><![CDATA[$this->db]]></code>
       <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
       <code><![CDATA[TransactionIsolationLevel]]></code>
       <code><![CDATA[\Doctrine\DBAL\ParameterType]]></code>
       <code><![CDATA[\Doctrine\DBAL\ParameterType]]></code>
@@ -196,6 +198,11 @@
       <code><![CDATA[\Doctrine\DBAL\Platforms\PostgreSQLPlatform]]></code>
       <code><![CDATA[\Doctrine\DBAL\Platforms\PostgreSQLPlatform]]></code>
       <code><![CDATA[\Doctrine\DBAL\Platforms\PostgreSQLPlatform]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Platforms\PostgreSQLPlatform]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Schema\ForeignKeyConstraint]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
       <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
       <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
       <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
@@ -438,6 +445,7 @@
     </EmptyArrayAccess>
     <UndefinedInterfaceMethod>
       <code><![CDATA[getInner]]></code>
+      <code><![CDATA[getInner]]></code>
     </UndefinedInterfaceMethod>
     <UnresolvableInclude>
       <code><![CDATA[include $path]]></code>

tests/Unit/Repository/IndexCacheTest.php

@@ -54,6 +54,24 @@ class IndexCacheTest extends TestCase {
 		$this->assertCount(12, self::hashTree($target));
 	}
 
+	/** Connecting a new server to a location with backups reports how far reading the index is. */
+	public function testOpeningReportsIndexProgress(): void {
+		$src = $this->tempDir();
+		for ($i = 0; $i < 6; $i++) {
+			file_put_contents("$src/f$i", random_bytes(3 * 1048576));
+		}
+		$backend = new LocalBackend($this->tempDir());
+		$keys = KeyRing::generate();
+		Repository::initWithKey($backend, $keys, $keys->wrap('pw'))->backupDirectory($src);
+		$files = count($backend->list('index'));
+		$seen = [];
+		Repository::openWithKey($backend, $keys, null, null, function (int $done, int $total) use (&$seen): void {
+			$seen[] = [$done, $total];
+		});
+		$this->assertCount($files, $seen);
+		$this->assertSame([$files, $files], end($seen));
+	}
+
 	/** The database dump reads in a read-only transaction: a pack that fills up then must not write the cache yet. */
 	public function testHeldCacheWritesWaitForRelease(): void {
 		$cache = new class implements IIndexCache {

tests/Unit/Repository/PruneTest.php

@@ -88,6 +88,33 @@ class PruneTest extends TestCase {
 		$this->assertSame(self::hashTree($src), self::hashTree($target));
 	}
 
+	public function testRestoreFollowsPacksRepackedByAnotherServer(): void {
+		// A disaster recovery test on a second server reads the location while the original
+		// server's weekly cleanup repacks it: the restore must not stop at a pack that moved.
+		$src = $this->tempDir();
+		$backend = new LocalBackend($this->tempDir());
+		$keys = KeyRing::generate();
+		$repo = Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
+		for ($i = 0; $i < 40; $i++) {
+			file_put_contents("$src/f$i", random_bytes(500000));
+		}
+		$a = $repo->backupDirectory($src);
+		for ($i = 0; $i < 40; $i++) {
+			if ($i % 5 !== 0) {
+				unlink("$src/f$i");
+			}
+		}
+		$b = $repo->backupDirectory($src, $a['snapshot']);
+		$reader = Repository::openWithKey($backend, $keys); // index loaded before the cleanup
+		$repo->forget($a['snapshot']);
+		$repo->purgeTrash(0);
+		$this->assertGreaterThan(0, $repo->prune(false, 0.5)['repacked']);
+
+		$target = $this->tempDir();
+		$reader->restore($b['snapshot'], $target);
+		$this->assertSame(self::hashTree($src), self::hashTree($target));
+	}
+
 	public function testUntrashRestoresAWorkingSnapshot(): void {
 		$src = $this->tempDir();
 		$backend = new LocalBackend($this->tempDir());

tests/integration/full-restore-roundtrip.sh

@@ -2,10 +2,14 @@
 # Disaster recovery: occ backup:key:import + backup:target:add + backup:restore:full on a
 # SECOND, fresh Nextcloud instance that never saw the first one, sharing only the backup
 # location (a local directory, bind-mounted into both containers) -- see PLAN.md 3.7.
-# Usage: full-restore-roundtrip.sh <nextcloud-image-tag>
-#   e.g. full-restore-roundtrip.sh 35-apache
+# Usage: full-restore-roundtrip.sh <nextcloud-image-tag> [sqlite|pgsql|mysql]
+#   e.g. full-restore-roundtrip.sh 35-apache pgsql
+# With pgsql or mysql the origin also has what broke real disaster recoveries: the Mail app with a synced
+# account (foreign keys between its tables) and Deck installed and then switched off (tables of
+# an app that is not enabled). The restore instance has neither; --install-apps adds Mail.
 set -euo pipefail
 IMAGE="nextcloud:${1:-35-apache}"
+DB="${2:-sqlite}"
 APP=$(cd "$(dirname "$0")/../.." && pwd)
 NET=ngb-frt-net
 SHARED=$(mktemp -d)
@@ -14,7 +18,7 @@ fail() { echo "FAIL: $*"; exit 1; }
 ok() { echo "ok   $*"; }
 
 cleanup() {
-	docker rm -fv ngb-frt-origin ngb-frt-restore >/dev/null 2>&1 || true
+	docker rm -fv ngb-frt-origin ngb-frt-restore ngb-frt-db-origin ngb-frt-db-restore ngb-frt-imap >/dev/null 2>&1 || true
 	docker network rm "$NET" >/dev/null 2>&1 || true
 	docker run --rm -v "$SHARED:/target" alpine sh -c 'rm -rf /target/*' >/dev/null 2>&1 || true
 	rmdir "$SHARED" 2>/dev/null || true
@@ -24,14 +28,33 @@ trap cleanup EXIT
 
 run_on() { docker exec -u www-data "$1" php occ "${@:2}"; }
 
+# Database settings for an instance: SQLite inside the container, or its own PostgreSQL container
+db_env() {
+	if [ "$DB" = pgsql ]; then
+		docker run -d --name "ngb-frt-db-$1" --network "$NET" -e POSTGRES_DB=nextcloud -e POSTGRES_USER=nextcloud \
+			-e POSTGRES_PASSWORD=nextcloud postgres:16-alpine >/dev/null
+		for i in $(seq 1 30); do docker exec "ngb-frt-db-$1" pg_isready -q 2>/dev/null && break; sleep 2; done
+		echo "-e POSTGRES_HOST=ngb-frt-db-$1 -e POSTGRES_DB=nextcloud -e POSTGRES_USER=nextcloud -e POSTGRES_PASSWORD=nextcloud"
+	elif [ "$DB" = mysql ]; then
+		docker run -d --name "ngb-frt-db-$1" --network "$NET" -e MARIADB_DATABASE=nextcloud -e MARIADB_USER=nextcloud \
+			-e MARIADB_PASSWORD=nextcloud -e MARIADB_ROOT_PASSWORD=nextcloud mariadb:11 >/dev/null
+		for i in $(seq 1 60); do docker exec "ngb-frt-db-$1" mariadb-admin ping -unextcloud -pnextcloud --silent >/dev/null 2>&1 && break; sleep 2; done
+		echo "-e MYSQL_HOST=ngb-frt-db-$1 -e MYSQL_DATABASE=nextcloud -e MYSQL_USER=nextcloud -e MYSQL_PASSWORD=nextcloud"
+	else
+		echo "-e SQLITE_DATABASE=nextcloud"
+	fi
+}
+
 docker network create "$NET" >/dev/null
-docker run -d --name ngb-frt-origin --network "$NET" -e SQLITE_DATABASE=nextcloud \
+ORIGIN_DB=$(db_env origin)
+# shellcheck disable=SC2086
+docker run -d --name ngb-frt-origin --network "$NET" $ORIGIN_DB \
 	-e NEXTCLOUD_ADMIN_USER=admin -e NEXTCLOUD_ADMIN_PASSWORD=admin \
 	-v "$APP:/var/www/html/custom_apps/ng_backup:ro" -v "$SHARED:/mnt/shared" "$IMAGE" >/dev/null
 for i in $(seq 1 90); do run_on ngb-frt-origin status 2>/dev/null | grep -q "installed: true" && break; sleep 3; done
 docker exec ngb-frt-origin chown www-data:www-data /var/www/html/custom_apps
 run_on ngb-frt-origin app:enable ng_backup >/dev/null
-ok "origin instance up"
+ok "origin instance up ($DB)"
 
 docker exec ngb-frt-origin sh -c "printf 'full restore roundtrip passphrase 2026\n' > /tmp/pass"
 run_on ngb-frt-origin backup:key:init --passphrase-file=/tmp/pass --label=CI >/dev/null || fail "key init"
@@ -45,6 +68,31 @@ NC_PASS=$(openssl rand -hex 16)
 docker exec -u www-data -e OC_PASS="$NC_PASS" ngb-frt-origin php occ user:add --password-from-env frtest >/dev/null
 docker exec ngb-frt-origin sh -c "mkdir -p /var/www/html/data/frtest/files/Docs && head -c 200000 /dev/urandom > /var/www/html/data/frtest/files/Docs/report.bin && echo 'hello disaster recovery' > /var/www/html/data/frtest/files/Docs/note.txt && chown -R www-data:www-data /var/www/html/data/frtest"
 run_on ngb-frt-origin files:scan frtest >/dev/null
+
+# SQL on an instance's own database (pgsql/mysql only)
+sql() {
+	if [ "$DB" = pgsql ]; then docker exec "ngb-frt-db-$1" psql -U nextcloud -d nextcloud -Atc "$2"
+	else docker exec "ngb-frt-db-$1" mariadb -unextcloud -pnextcloud -N -B nextcloud -e "$2"; fi
+}
+if [ "$DB" != sqlite ]; then
+	# Mail with a synced account: oc_mail_accounts points at oc_mail_mailboxes (foreign keys),
+	# while the restore loads tables in name order, accounts before mailboxes.
+	docker run -d --name ngb-frt-imap --network "$NET" -e MAILNAME=mail.domain.tld -e MAIL_ADDRESS=user@domain.tld \
+		-e MAIL_PASS=mypassword ghcr.io/christophwurst/docker-imap-devel:latest >/dev/null
+	run_on ngb-frt-origin app:install mail >/dev/null || fail "install mail on the origin"
+	run_on ngb-frt-origin config:system:set app.mail.verify-tls-peer --type=boolean --value=false >/dev/null
+	sleep 10
+	run_on ngb-frt-origin mail:account:create frtest Test user@domain.tld ngb-frt-imap 993 ssl user@domain.tld mypassword \
+		ngb-frt-imap 25 tls user@domain.tld mypassword >/dev/null || fail "mail account"
+	run_on ngb-frt-origin mail:account:sync -f 1 >/dev/null || fail "mail sync"
+	[ "$(sql origin 'select count(*) from oc_mail_accounts where drafts_mailbox_id is not null')" = 1 ] \
+		|| fail "the mail account does not point at its mailboxes"
+	# Deck installed and then switched off: its tables stay in the database and in the backup
+	run_on ngb-frt-origin app:install deck >/dev/null || fail "install deck on the origin"
+	run_on ngb-frt-origin app:disable deck >/dev/null
+	ok "origin has a synced Mail account and the tables of a disabled app"
+fi
+
 RUN_OUT=$(run_on ngb-frt-origin backup:run offsite -l disaster-test)
 SNAP=$(printf '%s\n' "$RUN_OUT" | head -1 | awk -F'snapshot ' '{print $2}' | tr -d ',')
 [ -n "$SNAP" ] || fail "no snapshot id from backup:run"
@@ -52,7 +100,9 @@ ok "test data backed up, snapshot $SNAP"
 
 docker cp ngb-frt-origin:/tmp/kit.json /tmp/ngb-frt-kit.json
 docker exec ngb-frt-origin sh -c "cat /tmp/pass" > /tmp/ngb-frt-pass
-docker run -d --name ngb-frt-restore --network "$NET" -e SQLITE_DATABASE=nextcloud \
+RESTORE_DB=$(db_env restore)
+# shellcheck disable=SC2086
+docker run -d --name ngb-frt-restore --network "$NET" $RESTORE_DB \
 	-e NEXTCLOUD_ADMIN_USER=admin -e NEXTCLOUD_ADMIN_PASSWORD=admin \
 	-v "$APP:/var/www/html/custom_apps/ng_backup:ro" -v "$SHARED:/mnt/shared" "$IMAGE" >/dev/null
 for i in $(seq 1 90); do run_on ngb-frt-restore status 2>/dev/null | grep -q "installed: true" && break; sleep 3; done
@@ -68,7 +118,7 @@ run_on ngb-frt-restore backup:target:add offsite local -a null::null -o datadir=
 run_on ngb-frt-restore backup:list offsite | grep -q "$SNAP" || fail "the origin's snapshot is not listed after connecting the location"
 ok "recovery kit imported, existing repository adopted, snapshot visible"
 
-OUT=$(run_on ngb-frt-restore backup:restore:full offsite "$SNAP" --no-interaction 2>&1) || {
+OUT=$(run_on ngb-frt-restore backup:restore:full offsite "$SNAP" --no-interaction --install-apps 2>&1) || {
 	printf '%s\n' "$OUT" | tail -40
 	docker exec ngb-frt-restore sh -c 'tail -c 6000 /var/www/html/data/nextcloud.log' || true
 	fail "restore:full"
@@ -84,7 +134,16 @@ docker exec ngb-frt-restore test -f /var/www/html/data/frtest/files/Docs/note.tx
 run_on ngb-frt-restore files:scan frtest >/dev/null || fail "files:scan fails after restore"
 ok "database, files and ng_backup's own state are all intact and usable after the restore"
 
+if [ "$DB" != sqlite ]; then
+	[ "$(sql restore "select count(*) from information_schema.tables where table_name = 'oc_deck_boards'")" = 1 ] || fail "the tables of the disabled app were not created"
+	[ "$(sql restore "select count(*) from oc_mail_accounts where drafts_mailbox_id is not null")" = 1 ] || fail "the mail account was not restored"
+	[ "$(sql restore "select count(*) from information_schema.table_constraints where constraint_type = 'FOREIGN KEY' and table_name like 'oc_mail_%'")" -gt 0 ] \
+		|| fail "the foreign keys of Mail are missing after the restore"
+	printf '%s\n' "$OUT" | grep -q "Created .* tables" || fail "the restore did not report the tables it created"
+	ok "tables of a disabled app created, Mail restored with its foreign keys"
+fi
+
 run_on ngb-frt-restore backup:run offsite -l post-restore-check >/dev/null || fail "a new backup after the restore fails"
 ok "the restored instance can run a new backup of its own"
 
-echo "FULL RESTORE ROUNDTRIP PASS"
+echo "FULL RESTORE ROUNDTRIP PASS ($DB)"