Db Connection Not Closed (ARCH3084)

Key typescript.performance.db-connection-not-closed · Severity error · Category performance

Opening a database connection/cursor and never releasing it drains the pool and eventually makes new requests wait for a connection and time out.

Incorrect

async function count(): Promise<number> {
  const client = await pool.connect();
  const res = await client.query("SELECT count(*) FROM users");
  return res.rows[0].count;
  // client is never returned to the pool
}

Correct

async function count(): Promise<number> {
  const client = await pool.connect();
  try {
    const res = await client.query("SELECT count(*) FROM users");
    return res.rows[0].count;
  } finally {
    client.release();
  }
}

Fix

Return connections/cursors to the pool with release/close inside a try/finally.