Asnycpg PostgreSQL 连接问题

Question

I'm using Python with asnycpg to interact with my PostgreSQL database. After some time, if I don't interact with it and then try to do so, I get an connection is closed error. Is this a server side config or client side config issue? How to solve it?

Answer 1

The database automatically closes the connection due to security reasons.

So I suggest you to open the connection to db just before running queries with asyncpg, and then to reclose the connection right afterwards.

Furthermore, you can manage the possible errors that you get when the connection is closed by properly rising exceptions.

Take a look at this example:

Import asyncpg
print("I'm going to run a query with asyncpg")

# if the connection to db is not opened, then open it
if not connection:
    # try to open the connection to db
    try:
        connection = await asyncpg.connect(
                host=YOUR_DATABASE_HOST,
                user=YOUR_DATABASE_USER,
                password=YOUR_DATABASE_PASS,
                database=YOUR_DATABASE_DB_NAME
            )
            except (Exception, asyncpg.ConnectionFailureError) as error:
                Print("Error while connecting to db: {}".format(error))
else:
    #connection already up and running
    pass

QUERY_STRING = """
    INSERT INTO my_table(field_1, field_2)
    VALUES ($1, $2);
"""

try:
    await connection.execute(QUERY_STRING, value_to_assign_to_field_1, value_to_assign_to_field_2)
    return None
# except (Exception, asyncpg.UniqueViolationError) as integrError:
    # print("You are violating unique constraint.")
except (Exception, asyncpg.ConnectionFailureError) as error:
    print("Connection to db has failed. Cannot add data.")
    return "{}".format(error)
finally:
    if (connection):
        await Utils.close_connection(connection)
    print("data has been added. closing the connection.")