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Following what we commented in How to close sqlalchemy connection in MySQL, I am checking the connections that SQLAlchemy creates into my database and I cannot manage to close them without exiting from Python.
If I run this code in a python console, it keeps the session opened until I exit from python:
from sqlalchemy.orm import sessionmaker from models import OneTable, get_engine engine = get_engine(database="mydb") session = sessionmaker(bind=engine)() results = session.query(OneTable.company_name).all() # some work with the data # session.close() and the only workaround I found to close it is to call engine.dispose() at the end.
As per the comments in the link I gave above, my question are now:
engine.dispose() necessary to close sessions?session.close() suffice?
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session. flush() communicates a series of operations to the database (insert, update, delete). The database maintains them as pending operations in a transaction.
The Session begins in a mostly stateless form. Once queries are issued or other objects are persisted with it, it requests a connection resource from an Engine that is associated with the Session , and then establishes a transaction on that connection.
Advertisements. In order to interact with the database, we need to obtain its handle. A session object is the handle to database. Session class is defined using sessionmaker() – a configurable session factory method which is bound to the engine object created earlier.
Return the first result of this Query or None if the result doesn't contain any row. first() applies a limit of one within the generated SQL, so that only one primary entity row is generated on the server side (note this may consist of multiple result rows if join-loaded collections are present).
There's a central confusion here over the word "session". I'm not sure here, but it appears like you may be confusing the SQLAlchemy Session with a MySQL @@session, which refers to the scope of when you first make a connection to MySQL and when you disconnect.
These two concepts are not the same. A SQLAlchemy Session generally represents the scope of one or more transactions, upon a particular database connection.
Therefore, the answer to your question as literally asked, is to call session.close(), that is, "how to properly close a SQLAlchemy session".
However, the rest of your question indicates you'd like some functionality whereby when a particular Session is closed, you'd like the actual DBAPI connection to be closed as well.
What this basically means is that you wish to disable connection pooling. Which as other answers mention, easy enough, use NullPool.
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