async def transfer_funds(self, from_account, to_account, amount):
    async with self.db.transaction():
        await self.db.execute(
            "UPDATE accounts SET balance = balance - ? WHERE id = ?",
            (amount, from_account)
        )
        await self.db.execute(
            "UPDATE accounts SET balance = balance + ? WHERE id = ?",
            (amount, to_account)
        )

pool = await asyncpg.create_pool(
    'postgresql://user:password@localhost/db',
    min_size=10,
    max_size=20
)

CREATE INDEX idx_user_email ON users(email);
CREATE INDEX idx_transaction_date ON transactions(created_at);