Innova Solutions Lead Data Engineer Interview Questions and Answers

Group data by column 'A', calculate mean of column 'B' and sum values in column 'C' for each group.

• Use groupby() function in pandas to group data by column 'A'

• Apply mean() function on column 'B' and sum() function on column 'C' for each group

• Example: df.groupby('A').agg({'B':'mean', 'C':'sum'})

deepcopy() creates a new object with completely independent copies of nested objects, while copy() creates a shallow copy.

• deepcopy() creates a new object and recursively copies all nested objects, while copy() creates a shallow copy of the top-level object only.

• Use deepcopy() when you need to create a deep copy of an object with nested structures, to avoid any references to the original object.

• Use copy() when you only ...read more

Python decorators are functions that modify the behavior of other functions. They are commonly used for adding functionality to existing functions without modifying their code.

• Decorators are defined using the @ symbol followed by the decorator function name.

• They can be used to measure the execution time of a function by wrapping the function with a timer decorator.

• Example: def timer(func): def wrapper(*args, **kwargs...read more

Set executor memory to 8GB and executor cores to 5 for optimal performance.

• Set spark.executor.memory to 8g

• Set spark.executor.cores to 5

• Set spark.default.parallelism to 8000

• Use Hadoop InputFormat to read data in 128MB chunks

Windowing functions are used to perform calculations on a subset of data within a larger dataset.

• Windowing functions are used to calculate running totals, moving averages, and rank functions.

• They are commonly used in time series analysis and financial analysis.

• Examples of windowing functions include ROW_NUMBER(), RANK(), DENSE_RANK(), and NTILE().

To patch specific db components to reduce downtime, follow these steps:

• Identify the specific components that need to be patched

• Plan the patching process during a scheduled maintenance window

• Backup the database before applying patches

• Apply patches to the specific components one by one

• Test the patched components to ensure they are functioning correctly

• Monitor the database for any issues post-patching

SQL architecture refers to the structure and components of a SQL database system.

• SQL architecture includes components like storage engine, query processor, and buffer manager.

• The storage engine manages data storage and retrieval, while the query processor processes SQL queries.

• The buffer manager handles caching and memory management to optimize performance.

• Examples of SQL architectures include MySQL, Oracle, and SQL Se

The role of an Oracle DBA is to manage and maintain Oracle databases to ensure they are secure, efficient, and reliable.

• Installing and upgrading Oracle software

• Configuring and monitoring database performance

• Backup and recovery of data

• Troubleshooting and resolving database issues

• Implementing security measures to protect data

• Managing users and permissions