InternalClientError: cannot switch to state 12

^{Originally posted by **amacfie-tc** August 21, 2023}
I received the following error, does anyone know what it means? In the SQLAlchemy engine, `pool_pre_ping` is set to `True`.
```
asyncpg.exceptions._base.InternalClientError: cannot switch to state 12; another operation (2) is in progress
Traceback (most recent call last):
[...]
status = (await session.execute(sel_status)).scalar()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/ext/asyncio/session.py", line 454, in execute
result = await greenlet_spawn(
^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/util/_concurrency_py3k.py", line 190, in greenlet_spawn
result = context.throw(*sys.exc_info())
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/orm/session.py", line 2262, in execute
return self._execute_internal(
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/orm/session.py", line 2134, in _execute_internal
conn = self._connection_for_bind(bind)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/orm/session.py", line 2001, in _connection_for_bind
return trans._connection_for_bind(engine, execution_options)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "", line 2, in _connection_for_bind
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/orm/state_changes.py", line 139, in _go
ret_value = fn(self, *arg, **kw)
^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/orm/session.py", line 1126, in _connection_for_bind
conn = bind.connect()
^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/engine/base.py", line 3264, in connect
return self._connection_cls(self)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/engine/base.py", line 145, in __init__
self._dbapi_connection = engine.raw_connection()
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/engine/base.py", line 3288, in raw_connection
return self.pool.connect()
^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/pool/base.py", line 452, in connect
return _ConnectionFairy._checkout(self)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/pool/base.py", line 1366, in _checkout
with util.safe_reraise():
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/util/langhelpers.py", line 147, in __exit__
raise exc_value.with_traceback(exc_tb)
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/pool/base.py", line 1304, in _checkout
result = pool._dialect._do_ping_w_event(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/engine/default.py", line 708, in _do_ping_w_event
return self.do_ping(dbapi_connection)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/sqlalchemy/dialects/postgresql/asyncpg.py", line 1117, in do_ping
dbapi_connection.ping()
asyncpg.exceptions._base.InternalClientError: cannot switch to state 12; another operation (2) is in progress
```