MariaDBConnector/Python 连接池获取池中每个连接的连接速度变慢

Question

I'm using the MariaDB/Python connector on Python 3.11, Linux Mint, latest version of MariaDB, etc and I can't for the life of me figure this out. I have a simple function called get_connection() that returns a Connection from mariadb.ConnectionPool , and with pool_size=1 , the response time in Postman is 75ms, but with pool_size=5 , the response time is 400ms. There is nothing else going on in this request except for a FastAPI Middleware that opens and closes this connection. There comes a threshold with this issue where it's simply faster to open a new connection per request, as opposed to using a ConnectionPool .

I expect get_connection() to have the same response time whether I have pool_size=5 or pool_size=64 .

Here is the code:

POOL = mariadb.ConnectionPool(
    host=os.environ.get("DATABASE_IP"),
    port=3306,
    user=os.environ.get("DATABASE_USER"),
    password=os.environ.get("DATABASE_PASSWORD"),
    pool_name="poolname",
    pool_size=5,
    pool_reset_connection=True
)


def get_connection() -> Connection:
    """
    Returns a DatabaseHandler object
    :return:
    """
    before = datetime.datetime.now()
    connection = POOL.get_connection()
    after = datetime.datetime.now()
    print((after - before).microseconds)
    return connection

Answer 1

We experienced the same problem when running internal benchmarks with connection pool instead of a single connection.

The problem is caused by unnecessary health check (sending MYSQL_PING) when iterating over unused connections.

Fix is planned for 1.1.6 (scheduled for mid Feb)

For tracking status of this issue, please check CONPY-245

Update (Feb 1): Issue has been fixed and will be available in 1.1.6 release:

$ python3.11 conpy245.py
Acquiring 100000 connections via Pool
Pool size: 64
Average time per connection: 19 ms

Acquiring 100000 connections without Pool
Average time per connection: 170 ms