psycopg2.OperationalError: FATAL: 抱歉，heroku 上已经有太多客户

Question

我尝试将我的 Flask 应用程序推送到 heroku，而我的应用程序使用 Postgres 作为数据库。但是，当我尝试使用此命令在 heroku 上迁移 db 时

heroku run python manage.py db init --app app

它为 psycopg2 和 sqlalchchemy 提供了“太多客户端”错误。

Running python manage.py db migrate on ⬢ petscom... up, run.5707 (Hobby)
Traceback (most recent call last):
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 2285, in _wrap_pool_connect
    return fn()
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 303, in unique_connection
    return _ConnectionFairy._checkout(self)
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 773, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 492, in checkout
    rec = pool._do_get()
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/pool/impl.py", line 238, in _do_get
    return self._create_connection()
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 308, in _create_connection
    return _ConnectionRecord(self)
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 437, in __init__
    self.__connect(first_connect_check=True)
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 657, in __connect
    pool.logger.debug("Error on connect(): %s", e)
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/util/langhelpers.py", line 69, in __exit__
    exc_value, with_traceback=exc_tb,
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 178, in raise_
    raise exception
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 652, in __connect
    connection = pool._invoke_creator(self)
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/engine/strategies.py", line 114, in connect
    return dialect.connect(*cargs, **cparams)
  File "/app/.heroku/python/lib/python3.6/site-packages/sqlalchemy/engine/default.py", line 488, in connect
    return self.dbapi.connect(*cargs, **cparams)
  File "/app/.heroku/python/lib/python3.6/site-packages/psycopg2/__init__.py", line 126, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
psycopg2.OperationalError: FATAL:  sorry, too many clients already
FATAL:  sorry, too many clients already

经过一番谷歌搜索，我尝试了：

1. heroku pg:killall
2. heroku 重启 这些都不起作用.....

我检查了 heroku pg，它显示 0/20 连接......

有人说不要将数据库连接放在循环中，但我必须检查数据库中是否有一些数据。这是我的代码：

try:
        connection = psycopg2.connect(user="postgres",
                                      password="pass",
                                      host="127.0.0.1",
                                      port="5432",
                                      database="pets")

        cursor = connection.cursor()

        select_all = "select * from pets"
        cursor.execute(select_all)

        # Check if api data in db and save to db
        for index in range(len(myData)):
            # if not exist in db => save to db
            key = myData[index]["animal_id"]
            exists = check_exists(key, cursor)
            if(exists):
                pass
            else:
                doSomething()

我可以连接到我本地的 postgres 数据库，但不能连接到 heroku 上的数据库。 我该如何处理这个问题？任何建议都会有所帮助:) 谢谢！

Answer 1

我遇到了类似的问题。我可以通过在环境中设置SQLALCHEMY_TRACK_MODIFICATIONS=False、销毁数据库并创建一个新数据库来修复它。

您可以通过转到https://data.heroku.com/datastores，打开数据库，转到设置，然后选择“销毁数据库”来销毁它。

然后像往常一样提供一个新的。