#288: reset schema before pg_restore — partitioned tables broke --clean

Since #224 read_events is partitioned; the dump carries per-partition
primary keys as own entries, and pg_restore --clean emitted DROP
CONSTRAINT against inherited constraints, which PostgreSQL refuses. The
restore then reported FAILED although the content was restored. Dropping
and recreating the public schema first makes every --clean drop a no-op
and the restore faithful: objects created after the backup no longer
survive. Verified in the isolated environment of #220 (set
20260731-132200, exit 0, readyz green).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AUtYMxwTCMHG9mVHnwbFg8

apps/backup/src/pg.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, it } from 'vitest';
+
+import { pgEnvFromUrl, pgRestoreArgs, schemaResetArgs, schemaResetSql } from './pg.js';
+
+describe('pgEnvFromUrl', () => {
+  it('maps the URL onto libpq env vars, never argv', () => {
+    expect(pgEnvFromUrl('postgresql://user:p%40ss@db:5433/dorfteich')).toEqual({
+      PGHOST: 'db',
+      PGPORT: '5433',
+      PGUSER: 'user',
+      PGPASSWORD: 'p@ss',
+      PGDATABASE: 'dorfteich',
+    });
+  });
+});
+
+describe('restore command plan (issue #288)', () => {
+  it('resets the schema first — --clean alone cannot drop inherited partition PKs', () => {
+    expect(schemaResetSql).toBe('DROP SCHEMA IF EXISTS public CASCADE; CREATE SCHEMA public;');
+    expect(schemaResetArgs('dorfteich')).toEqual([
+      '--dbname',
+      'dorfteich',
+      '--set',
+      'ON_ERROR_STOP=1',
+      '--command',
+      schemaResetSql,
+    ]);
+  });
+
+  it('keeps --clean --if-exists as no-op belt and braces on the empty schema', () => {
+    expect(pgRestoreArgs('dorfteich', '/backups/x.dump')).toEqual([
+      '--clean',
+      '--if-exists',
+      '--no-owner',
+      '--dbname',
+      'dorfteich',
+      '/backups/x.dump',
+    ]);
+  });
+});

apps/backup/src/pg.ts

@@ -39,16 +39,32 @@ export async function pgDump(databaseUrl: string, outFile: string): Promise<void
 }
 
 /**
- * Restores a custom-format dump into the live database. `--clean
+ * Run before `pg_restore`: dropping and recreating the schema makes every
- * --if-exists` drops recreated objects first, so the restore lands on a
+ * `--clean` drop a no-op and the restore faithful — objects created after
- * database that may still hold newer state (the runbook stops the app
+ * the backup do not survive it. Relying on `--clean` alone fails on
- * services, not the db container).
+ * partitioned tables: the dump carries per-partition primary keys as own
+ * entries, and the matching drops hit *inherited* constraints on the live
+ * database, which PostgreSQL refuses (issue #288). The schema holds no
+ * extension objects, so the CASCADE is bounded to our own objects.
+ */
+export const schemaResetSql = 'DROP SCHEMA IF EXISTS public CASCADE; CREATE SCHEMA public;';
+
+export function schemaResetArgs(database: string): string[] {
+  return ['--dbname', database, '--set', 'ON_ERROR_STOP=1', '--command', schemaResetSql];
+}
+
+export function pgRestoreArgs(database: string, dumpFile: string): string[] {
+  return ['--clean', '--if-exists', '--no-owner', '--dbname', database, dumpFile];
+}
+
+/**
+ * Restores a custom-format dump into the live database: schema reset (see
+ * above), then `pg_restore`. `--clean --if-exists` stays as belt and braces
+ * — against the empty schema all its drops are no-ops (the runbook stops
+ * the app services, not the db container).
  */
 export async function pgRestore(databaseUrl: string, dumpFile: string): Promise<void> {
   const database = pgEnvFromUrl(databaseUrl).PGDATABASE ?? '';
-  await runPgTool(
+  await runPgTool('psql', schemaResetArgs(database), databaseUrl);
-    'pg_restore',
+  await runPgTool('pg_restore', pgRestoreArgs(database, dumpFile), databaseUrl);
-    ['--clean', '--if-exists', '--no-owner', '--dbname', database, dumpFile],
-    databaseUrl,
-  );
 }

docs/architecture/operations.md

@@ -79,7 +79,7 @@ monitoring, structured logs, backup alerting — no dedicated metrics stack.
 - **Restore runbook** (also the Prod-relocation procedure) — automated by
   `deploy/backup/restore.sh <backup-id>`, run from the stage directory:
   1. stop the app services (`web`, `api`, `collab`; the db stays up),
-  2. restore DB: `pg_restore --clean --if-exists` into the `db` container,
+  2. restore DB: schema reset + `pg_restore` into the `db` container (#288),
   3. restore volume: unpack the matching uploads/plugins archive,
   4. `docker compose up -d`, verify `/readyz`, spot-check a page + a file.
 - **Drills** (issue #87): monthly automated restore of the latest backup

docs/operations/restore-runbook.md

@@ -17,7 +17,8 @@ On the stage host, from the stage directory (`/srv/DOCKER/dorfteich-<stage>/`):
    id in `status.json` → `lastSuccess.backupId`.
 2. **Run the automated runbook:** `./restore.sh <backup-id>`
    (`deploy/backup/restore.sh`). It stops `web`/`api`/`collab` (the db stays
-   up), replays the dump with `pg_restore --clean --if-exists` and unpacks
+   up), resets the `public` schema and replays the dump with `pg_restore`
+   (#288 — objects created after the backup do not survive) and unpacks
    the volume archive through the backup sidecar image, starts the stack,
    and polls `/readyz`.
 3. **Verify:** `/readyz` fully green, spot-check one page and one uploaded