Database backend optimization in Apache Airflow - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the database connection URI in Airflow configuration.

Apache Airflow

[core]
sql_alchemy_conn = [1]

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

Asqlite:///airflow.db

Bpostgresql+psycopg2://user:pass@localhost/airflow

Cmysql://user:pass@localhost/airflow

Doracle://user:pass@localhost/airflow

Attempts:

3 left

💡 Hint

Common Mistakes

Using SQLite URI for production environment.

Forgetting the driver name in the URI.

The correct URI format for PostgreSQL with psycopg2 driver is postgresql+psycopg2://user:pass@localhost/airflow. This is commonly used for production Airflow setups.

2fill in blank

medium

Complete the command to initialize the Airflow metadata database.

Apache Airflow

airflow db [1]

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

Ainit

Breset

Cmigrate

Dupgrade

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'upgrade' which is for updating an existing database.

Using 'reset' which deletes data.

The command airflow db init initializes the metadata database, creating the necessary tables and applying initial migrations.

3fill in blank

hard

Fix the error in the SQLAlchemy connection string by choosing the correct driver name.

Apache Airflow

sql_alchemy_conn = postgresql+[1]://user:pass@localhost/airflow

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

Apsycopg2

Bcx_oracle

Cmysqlconnector

Dsqlite

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'mysqlconnector' which is for MySQL.

Using 'sqlite' which is for SQLite databases.

The correct driver for PostgreSQL in SQLAlchemy connection strings is psycopg2. Other options are for different databases.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that filters tasks with retries greater than 3.

Apache Airflow

filtered_tasks = {task_id: task for task_id, task in tasks.items() if task.[1] [2] 3}

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Aretries

B>

C<

Dmax_retries

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'max_retries' which is not a standard attribute.

Using '<' instead of '>' causing wrong filtering.

The attribute retries holds the retry count. We filter tasks where retries are greater than 3 using the '>' operator.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps task IDs to their owner names for tasks with priority above 5.

Apache Airflow

owners = { [1]: [2].owner for [3], [2] in dag.tasks.items() if [2].priority_weight > 5 }

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

Atask_id

Btask

Ctask_key

Dtask_obj

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same variable name for both key and value in the loop.

Using incorrect variable names causing syntax errors.

The dictionary comprehension uses task_id as key, task as value variable, and task_key as the loop variable for keys in dag.tasks.items().