Connection pooling in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the connection pool class from SQLAlchemy.

Flask

from sqlalchemy.pool import [1]

Drag options to blanks, or click blank then click option'

AConnectionPool

BQueuePool

CPoolManager

DSessionPool

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-existent class like ConnectionPool.

Confusing session management classes with pool classes.

The QueuePool is the default connection pool implementation in SQLAlchemy used with Flask.

2fill in blank

medium

Complete the code to create an engine with a connection pool size of 5.

Flask

engine = create_engine('sqlite:///app.db', pool_size=[1])

Drag options to blanks, or click blank then click option'

A5

B0

C1

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Setting pool_size to 0 disables pooling.

Using a number too large or too small for the task.

Setting pool_size=5 limits the pool to 5 connections.

3fill in blank

hard

Fix the error in the code to correctly dispose the connection pool.

Flask

engine.[1]()

Drag options to blanks, or click blank then click option'

Arelease

Bclose

Cshutdown

Ddispose

Attempts:

3 left

💡 Hint

Common Mistakes

Using close() which only closes one connection.

Using shutdown() which is not a method on engine.

The dispose() method properly closes all connections in the pool.

4fill in blank

hard

Fill both blanks to configure the engine with a max overflow of 10 and a pool recycle time of 3600 seconds.

Flask

engine = create_engine('mysql://user:pass@localhost/db', pool_size=5, pool_overflow=[1], pool_recycle=[2])

Drag options to blanks, or click blank then click option'

A10

B3600

C300

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the values between pool_overflow and pool_recycle.

Using zero for pool_overflow disables overflow connections.

pool_overflow=10 allows 10 extra connections beyond pool_size.
pool_recycle=3600 recycles connections after 1 hour.

5fill in blank

hard

Fill all three blanks to create a scoped session with the engine and bind it properly.

Flask

Session = scoped_session(sessionmaker(bind=[1], autoflush=[2], autocommit=[3]))

Drag options to blanks, or click blank then click option'

Aengine

BTrue

CFalse

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Setting autocommit to True which is deprecated.

Not binding the session to the engine.

Bind the session to engine, set autoflush=False and autocommit=False for manual control.