10+ Cognizant Gcp Data Engineer Interview Questions and Answers

Bigquery is a cloud-based data warehousing tool used for analyzing large datasets quickly. Pubsub is a messaging service, Dataflow is a data processing tool, and Cloud Storage is a scalable object storage service.

• Bigquery is used for analyzing large datasets quickly

• Pubsub is a messaging service used for asynchronous communication between applications

• Dataflow is a data processing tool used for batch and stream processing

• Cloud Storage is a scalable object storage service used f...read more

GCP BigQuery is a serverless, highly scalable, and cost-effective data warehouse for analyzing big data sets.

• BigQuery is a fully managed, petabyte-scale data warehouse that enables super-fast SQL queries using the processing power of Google's infrastructure.

• BigQuery's architecture includes storage, Dremel execution engine, and SQL layer.

• Cloud Composer is a managed workflow orchestration service that helps you create, schedule, and monitor pipelines using Apache Airflow.

• DAG (D...read more

Use 'bq show' command to display the schema of a table in BigQuery.

• Use 'bq show' command followed by the dataset and table name to display the schema.

• The schema includes the column names, data types, and mode (nullable or required).

• Example: bq show project_id:dataset.table_name

The GCP services used in our project include BigQuery, Dataflow, Pub/Sub, and Cloud Storage.

• BigQuery for data warehousing and analytics

• Dataflow for real-time data processing

• Pub/Sub for messaging and event ingestion

• Cloud Storage for storing data and files

To schedule a job to trigger every hour in Airflow, you can use the Cron schedule interval

• Define a DAG (Directed Acyclic Graph) in Airflow

• Set the schedule_interval parameter to '0 * * * *' to trigger the job every hour

• Example: schedule_interval='0 * * * *'

Use Python's slicing feature to display a string in reverse order.

• Use string slicing with a step of -1 to reverse the string.

• Example: 'hello'[::-1] will output 'olleh'.

Various data sources such as databases, APIs, files, and streaming services are used for data ingestion and processing.

• Databases (e.g. MySQL, PostgreSQL)

• APIs (e.g. RESTful APIs)

• Files (e.g. CSV, JSON)

• Streaming services (e.g. Kafka, Pub/Sub)

BigQuery does not have fixed slots, it dynamically allocates resources based on the query requirements.

• BigQuery does not have a fixed number of slots like traditional databases.

• It dynamically allocates resources based on the query requirements.

• The number of slots available for a query can vary depending on the complexity and size of the query.

• BigQuery's serverless architecture allows it to scale automatically to handle large workloads.

Leaf nodes are the bottom nodes in a tree structure, while columnar storage stores data in columns rather than rows.

• Leaf nodes are the end nodes in a tree structure, containing actual data or pointers to data.

• Columnar storage stores data in columns rather than rows, allowing for faster query performance on specific columns.

• Columnar storage is commonly used in data warehouses and analytics databases.

• Leaf nodes are important for efficient data retrieval in tree-based data struc...read more

Using bq commands to create a table and load a CSV file in Google BigQuery

• Use 'bq mk' command to create a new table in BigQuery

• Use 'bq load' command to load a CSV file into the created table

• Specify schema and source format when creating the table

• Specify source format and destination table when loading the CSV file

• Example: bq mk --table dataset.table_name schema.json

• Example: bq load --source_format=CSV dataset.table_name data.csv

Cloud Functions are event-driven functions that run in response to cloud events.

• Serverless functions that automatically scale based on demand

• Can be triggered by events from various cloud services

• Supports multiple programming languages like Node.js, Python, etc.