Flipside AI Data Annotation Engineer Interview Questions and Answers

Optimizing SQL queries involves using indexes, avoiding unnecessary joins, and optimizing the query structure.

• Use indexes on columns frequently used in WHERE clauses

• Avoid using SELECT * and only retrieve necessary columns

• Optimize joins by using INNER JOIN instead of OUTER JOIN when possible

• Use EXPLAIN to analyze query performance and make necessary adjustments

Performance optimization in Spark involves tuning configurations, optimizing code, and utilizing caching.

• Tune Spark configurations such as executor memory, number of executors, and shuffle partitions.

• Optimize code by reducing unnecessary shuffles, using efficient transformations, and avoiding unnecessary data movements.

• Utilize caching to store intermediate results in memory and avoid recomputation.

• Example: In my projec...read more

SparkContext is the main entry point for Spark functionality, while SparkSession is the entry point for Spark SQL.

• SparkContext is the entry point for low-level API functionality in Spark.

• SparkSession is the entry point for Spark SQL functionality.

• SparkContext is used to create RDDs (Resilient Distributed Datasets) in Spark.

• SparkSession provides a unified entry point for reading data from various sources and performing

When a spark job is submitted, various steps are executed at the backend to process the job.

• The job is submitted to the Spark driver program.

• The driver program communicates with the cluster manager to request resources.

• The cluster manager allocates resources (CPU, memory) to the job.

• The driver program creates DAG (Directed Acyclic Graph) of the job stages and tasks.

• Tasks are then scheduled and executed on worker nodes ...read more

Calculate second highest salary using SQL and pyspark

• Use SQL query with ORDER BY and LIMIT to get the second highest salary

• In pyspark, use orderBy() and take() functions to achieve the same result

The two types of modes for Spark architecture are standalone mode and cluster mode.

• Standalone mode: Spark runs on a single machine with a single JVM and is suitable for development and testing.

• Cluster mode: Spark runs on a cluster of machines managed by a cluster manager like YARN or Mesos for production workloads.

Client mode is better for very less latency due to direct communication with the cluster.

• Client mode allows direct communication with the cluster, reducing latency.

• Standalone mode requires an additional layer of communication, increasing latency.

• Client mode is preferred for real-time applications where low latency is crucial.

Different types of joins available in Databricks include inner join, outer join, left join, right join, and cross join.

• Inner join: Returns only the rows that have matching values in both tables.

• Outer join: Returns all rows when there is a match in either table.

• Left join: Returns all rows from the left table and the matched rows from the right table.

• Right join: Returns all rows from the right table and the matched rows ...read more

Implementing fault tolerance in a data pipeline involves redundancy, monitoring, and error handling.

• Use redundant components to ensure continuous data flow

• Implement monitoring tools to detect failures and bottlenecks

• Set up automated alerts for immediate response to issues

• Design error handling mechanisms to gracefully handle failures

• Use checkpoints and retries to ensure data integrity

AutoLoader is a feature in data engineering that automatically loads data from various sources into a data warehouse or database.

• Automates the process of loading data from different sources

• Reduces manual effort and human error

• Can be scheduled to run at specific intervals

• Examples: Apache Nifi, AWS Glue

To connect to different services in Azure, you can use Azure SDKs, REST APIs, Azure Portal, Azure CLI, and Azure PowerShell.

• Use Azure SDKs for programming languages like Python, Java, C#, etc.

• Utilize REST APIs to interact with Azure services programmatically.

• Access and manage services through the Azure Portal.

• Leverage Azure CLI for command-line interface interactions.

• Automate tasks using Azure PowerShell scripts.

Linked Services are connections to external data sources or destinations in Azure Data Factory.

• Linked Services define the connection information needed to connect to external data sources or destinations.

• They can be used in Data Factory pipelines to read from or write to external systems.

• Examples of Linked Services include Azure Blob Storage, Azure SQL Database, and Amazon S3.

Bigtable is a NoSQL database for real-time analytics, while BigQuery is a fully managed data warehouse for running SQL queries.

• Bigtable is a NoSQL database designed for real-time analytics and high throughput, while BigQuery is a fully managed data warehouse for running SQL queries.

• Bigtable is used for storing large amounts of semi-structured data, while BigQuery is used for analyzing structured data using SQL queries.

• ...read more

To remove duplicate rows from BigQuery, use the DISTINCT keyword. To find the month of a given date, use the EXTRACT function.

• To remove duplicate rows, use SELECT DISTINCT * FROM table_name;

• To find the month of a given date, use SELECT EXTRACT(MONTH FROM date_column) AS month_name FROM table_name;

• Make sure to replace 'table_name' and 'date_column' with the appropriate values in your query.

The operator used in Composer to move data from GCS to BigQuery is the GCS to BigQuery operator.

• The GCS to BigQuery operator is used in Apache Airflow, which is the underlying technology of Composer.

• This operator allows you to transfer data from Google Cloud Storage (GCS) to BigQuery.

• You can specify the source and destination parameters in the operator to define the data transfer process.

Code to square each element in the input array.

• Iterate through the input array and square each element.

• Store the squared values in a new array to get the desired output.

Dataflow is a fully managed stream and batch processing service, while Dataproc is a managed Apache Spark and Hadoop service.

• Dataflow is a serverless data processing service that automatically scales to handle your data, while Dataproc is a managed Spark and Hadoop service that requires you to provision and manage clusters.

• Dataflow is designed for both batch and stream processing, allowing you to process data in real-t...read more

BigQuery architecture includes storage, execution, and optimization components for efficient query processing.

• BigQuery stores data in Capacitor storage system for fast access.

• Query execution is distributed across multiple nodes for parallel processing.

• Query optimization techniques include partitioning tables, clustering tables, and using query cache.

• Using partitioned tables can help eliminate scanning unnecessary data.

• ...read more

RDD vs dataframe vs dataset in PySpark

• RDD (Resilient Distributed Dataset) is the basic abstraction in PySpark, representing a distributed collection of objects

• Dataframe is a distributed collection of data organized into named columns, similar to a table in a relational database

• Dataset is a distributed collection of data with the ability to use custom classes for type safety and user-defined functions

• Dataframes and Data...read more

I have a background in data analysis with experience in using tools like Python, SQL, and Tableau.

• I have a degree in Statistics and have worked as a Data Analyst for 3 years.

• My daily activities include cleaning and analyzing data, creating visualizations, and presenting insights to stakeholders.

• I use Python for data manipulation and analysis, SQL for querying databases, and Tableau for creating interactive dashboards.

• I...read more

Advanced Excel and Power BI are tools used for data analysis and visualization in companies and for clients.

• Advanced Excel allows for complex data manipulation, analysis, and visualization using features like pivot tables, macros, and VBA programming.

• Power BI is a business analytics tool that provides interactive visualizations and business intelligence capabilities, connecting to various data sources.

• These tools are u...read more

I have extensive experience in using Advanced Excel and Power BI for data analysis projects.

• Created complex formulas and macros in Excel to automate data processing tasks

• Designed interactive dashboards in Power BI to visualize and analyze data trends

• Integrated data from multiple sources into Power BI for comprehensive analysis

• Used Power Query and Power Pivot in Excel to manipulate and analyze large datasets

• Provided dat...read more

Credit and operations concepts in relation to KYC procedures and client data privacy.

• Credit refers to the extension of money or resources to a client based on their financial history and ability to repay.

• Operations involve the day-to-day processes and procedures within a financial institution to ensure smooth functioning.

• KYC procedures are used to verify the identity of clients to prevent fraud and money laundering.

• Pri...read more