reachable postgres does not use the expected embedded data d

Error message

reachable postgres does not use the expected embedded data directory

What it means

Error "reachable postgres does not use the expected embedded data directory" thrown in paperclipai/paperclip.

Source

Thrown at packages/db/src/migration-runtime.ts:112

): Promise<MigrationConnection> {
  const EmbeddedPostgres = await loadEmbeddedPostgresCtor();
  await prepareEmbeddedPostgresNativeRuntime();
  const selectedPort = await findAvailablePort(preferredPort);
  const postmasterPidFile = path.resolve(dataDir, "postmaster.pid");
  const pgVersionFile = path.resolve(dataDir, "PG_VERSION");
  const runningPid = readRunningPostmasterPid(postmasterPidFile);
  const runningPort = readPidFilePort(postmasterPidFile);
  const preferredAdminConnectionString = `postgres://paperclip:paperclip@127.0.0.1:${preferredPort}/postgres`;
  const logBuffer = createEmbeddedPostgresLogBuffer();

  if (!runningPid && existsSync(pgVersionFile)) {
    try {
      const actualDataDir = await getPostgresDataDirectory(preferredAdminConnectionString);
      const matchesDataDir =
        typeof actualDataDir === "string" &&
        path.resolve(actualDataDir) === path.resolve(dataDir);
      if (!matchesDataDir) {
        throw new Error("reachable postgres does not use the expected embedded data directory");
      }
      await ensurePostgresDatabase(preferredAdminConnectionString, "paperclip");
      process.emitWarning(
        `Adopting an existing PostgreSQL instance on port ${preferredPort} for embedded data dir ${dataDir} because postmaster.pid is missing.`,
      );
      return {
        connectionString: `postgres://paperclip:paperclip@127.0.0.1:${preferredPort}/paperclip`,
        source: `embedded-postgres@${preferredPort}`,
        stop: async () => {},
      };
    } catch {
      // Fall through and attempt to start the configured embedded cluster.
    }
  }

  if (runningPid) {
    const port = runningPort ?? preferredPort;
    const adminConnectionString = `postgres://paperclip:paperclip@127.0.0.1:${port}/postgres`;

View on GitHub (pinned to 120ae5428f)

Solutions

Point the app at the correct embedded data directory or remove the stale directory so a fresh embedded instance is initialized.
If another Postgres already uses that port, set DATABASE_URL to it explicitly.

When it happens

Trigger: Thrown at packages/db/src/migration-runtime.ts:112 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of paperclipai/paperclip@120ae5428f (2026-08-18). Data as JSON: /api/errors/5cfd9ee2f2b59c13. Report an issue: GitHub.