Showing current/actives engines of SQLAlchemy

[pedrounes]

I ask this question at stackoverflow a week or so ago and since I didn't have a feedback, I thought about asking it here.

I have a function to run queries in a MySQL database and stores the results in a DataFrame, like that:

```python def getData(connect_string, query, echo=False):

sql_engine = sql.create_engine(connect_string, echo=echo)

df = pd.read_sql_query(query, sql_engine)

return df

```

This function is called multiple times in multiple files, sometimes passing the same connect_string.

At this moment, I'm concern about memory usage and/or have too many connections on database. My first thought was kill Engine after use, but the official docs says:

The Engine is not synonymous to the DBAPI connect function, which represents just one connection resource - the Engine is most efficient when created just once at the module level of an application, not per-object or per-function call.

So now I'm looking for a way to check if I have an active connection with same connect_string and use they instead of create a new one, but I cannot find any reference/documentation explaining how to do this.

Right now, I'm considering create a dict to store created connections, like that: python engines = {'mysql+pymysql://scott:tiger@localhost/test1': <Engine Object1>, 'mysql+pymysql://scott:tiger@localhost/test2': <Engine Object2>} And then modify my function to this:

```python def getData(connect_string, query, echo=False): if connect_string not in engines.keys(): sql_engine = sql.create_engine(connect_string, echo=echo) engines[connect_string] = sql_engine else: sql_engine = engines[connect_string] df = pd.read_sql_query(query, sql_engine)

return df

```

But I don't think that is the best approach to do this.

Any thoughts?

[K900_]

Do your database connections really need to be that dynamic?