15-Day Databricks for Data Engineering Master Guide

 

For 4–10 Years Experienced Data Engineers


Objective

This guide is designed to:

  • Build strong Databricks fundamentals

  • Understand Lakehouse architecture

  • Learn real-time enterprise implementations

  • Master Databricks workflows and optimization

  • Build scalable ETL pipelines

  • Prepare for senior-level interviews

Target Audience:

  • Data Engineers

  • Azure Databricks Engineers

  • PySpark Developers

  • Big Data Engineers

  • ETL Developers

  • Cloud Data Platform Engineers

Daily Time Commitment:

  • 3 Hours Per Day

  • 15 Days Total

Learning Strategy:

  • 20% Theory

  • 80% Hands-On Practice

Goal:

  • Understand Databricks architecture deeply

  • Build production-grade ETL pipelines

  • Optimize Spark workloads

  • Implement Delta Lake solutions

  • Handle enterprise-scale data engineering workflows


Daily Learning Structure

Hour 1 – Learn Concepts

Focus on:

  • Understanding WHY Databricks is used

  • Architecture understanding

  • Real-time implementation patterns

  • Optimization strategies

Avoid:

  • Memorizing notebook syntax blindly

  • Watching endless tutorials


Hour 2 – Hands-On Coding

Focus on:

  • Writing PySpark code

  • Building notebooks

  • Creating ETL workflows

  • Implementing Delta Lake


Hour 3 – Real-Time Scenarios

Focus on:

  • Optimization

  • Cluster tuning

  • Job troubleshooting

  • Pipeline failures

  • Incremental processing

  • Production deployment thinking


SECTION 1 – DATABRICKS FUNDAMENTALS

Topics:

  • What is Databricks

  • Why Databricks

  • Lakehouse Architecture

  • Databricks Workspace

  • Components Overview


WHAT IS DATABRICKS

Databricks is a cloud-based unified analytics platform built on Apache Spark.

Purpose:

  • Big data processing

  • Data engineering

  • Data science

  • Machine learning

  • Streaming analytics


WHY DATABRICKS IS USED

Problems Databricks Solves:

  • Complex Spark management

  • Distributed ETL processing

  • Large-scale analytics

  • Collaborative notebook development

  • Data lake optimization


LAKEHOUSE ARCHITECTURE

Critical Interview Topic.

Understand:

  • Data Lake

  • Data Warehouse

  • Lakehouse

  • Bronze Layer

  • Silver Layer

  • Gold Layer

Benefits:

  • Unified analytics

  • ACID transactions

  • Scalability

  • Governance


DATABRICKS WORKSPACE

Components:

  • Workspace

  • Clusters

  • Notebooks

  • Jobs

  • Repos

  • SQL Warehouses

  • Unity Catalog


SECTION 2 – DATABRICKS ARCHITECTURE

Topics:

  • Control Plane

  • Data Plane

  • Clusters

  • Drivers

  • Executors

  • DBFS


CONTROL PLANE

Managed by Databricks.

Responsibilities:

  • Notebook management

  • Cluster orchestration

  • Job scheduling

  • Access control


DATA PLANE

Managed in customer cloud account.

Responsibilities:

  • Data processing

  • Spark execution

  • Data storage interaction


CLUSTERS

Critical Topic.

Types:

  • All-purpose clusters

  • Job clusters

  • Single node clusters

Topics:

  • Autoscaling

  • Cluster policies

  • Runtime versions

  • Worker nodes


DRIVER AND EXECUTORS

Understand:

  • Task execution

  • Memory management

  • Distributed processing

  • Job execution flow


DBFS (DATABRICKS FILE SYSTEM)

Purpose:
Distributed storage abstraction.

Use Cases:

  • File storage

  • Intermediate datasets

  • ETL staging


SECTION 3 – NOTEBOOKS

Topics:

  • Notebook creation

  • Languages support

  • Markdown

  • Widgets

  • Magic commands


NOTEBOOKS

Supported Languages:

  • Python

  • SQL

  • Scala

  • R


MAGIC COMMANDS

Important Commands:

  • %python

  • %sql

  • %fs

  • %run

  • %md

Practice:

  • Cross-language execution

  • Reusable notebook execution


WIDGETS

Purpose:
Parameterize notebooks.

Real-Time Usage:

  • Dynamic ETL pipelines

  • Environment handling

  • Parameterized jobs


SECTION 4 – PYSPARK IN DATABRICKS

Topics:

  • SparkSession

  • DataFrames

  • Transformations

  • Actions

  • Built-in functions

  • UDFs


DATAFRAME OPERATIONS

Practice:

  • select

  • filter

  • withColumn

  • joins

  • aggregations

  • sorting

  • distinct


BUILT-IN FUNCTIONS

Critical Topic.

Functions:

  • col

  • when

  • lit

  • regexp_replace

  • explode

  • split

  • concat

  • current_timestamp

Prefer built-in functions over Python UDFs.


UDFS

Topics:

  • Python UDF

  • Pandas UDF

Important:
Avoid excessive Python UDF usage.

Why:

  • Serialization overhead

  • Reduced optimization


SECTION 5 – READING AND WRITING DATA

Topics:

  • CSV

  • JSON

  • Parquet

  • Delta


READ CSV

Practice:

  • Header handling

  • Schema definition

  • Null handling

  • Corrupt records


READ JSON

Practice:

  • Nested JSON

  • Multiline JSON

  • Flattening structures


PARQUET FILES

Why Parquet:

  • Columnar storage

  • Compression

  • Predicate pushdown

  • Faster analytics


DELTA FORMAT

Most Important Databricks Topic.

Features:

  • ACID transactions

  • Time travel

  • Merge support

  • Schema evolution

  • Optimized reads


WRITE OPERATIONS

Practice:

  • Append

  • Overwrite

  • Merge

  • Partitioned writes


SECTION 6 – DELTA LAKE

Topics:

  • Delta tables

  • Merge

  • Upserts

  • Time travel

  • Vacuum

  • Optimize

  • Z-ordering


DELTA TABLES

Purpose:
Reliable and optimized storage.

Real-Time Usage:

  • Incremental pipelines

  • Historical tracking

  • Data lake reliability


MERGE INTO

Critical Interview Topic.

Use Cases:

  • Upserts

  • CDC processing

  • SCD Type 2


TIME TRAVEL

Purpose:
Access historical table versions.

Use Cases:

  • Auditing

  • Recovery

  • Debugging


VACUUM

Purpose:
Remove obsolete files.

Important:
Understand retention periods.


OPTIMIZE + ZORDER

Purpose:
Improve query performance.

Topics:

  • File compaction

  • Data skipping

  • Query optimization


SECTION 7 – DATABRICKS SQL

Topics:

  • SQL Warehouses

  • Databricks SQL

  • Query optimization

  • Dashboards


DATABRICKS SQL

Use Cases:

  • Reporting

  • BI dashboards

  • Adhoc analytics

  • SQL-based transformations


SQL WAREHOUSES

Purpose:
Dedicated SQL compute.

Topics:

  • Serverless

  • Classic

  • Pro warehouses


SECTION 8 – WORKFLOWS AND JOBS

Topics:

  • Jobs

  • Task orchestration

  • Scheduling

  • Dependencies

  • Notifications


DATABRICKS JOBS

Purpose:
Automate pipelines.

Practice:

  • Schedule ETL jobs

  • Trigger notebooks

  • Retry handling

  • Failure notifications


MULTI-TASK WORKFLOWS

Topics:

  • Sequential tasks

  • Parallel tasks

  • Dependency management


SECTION 9 – UNITY CATALOG

Topics:

  • Governance

  • Access control

  • Data lineage

  • Catalogs

  • Schemas


UNITY CATALOG

Critical Enterprise Topic.

Benefits:

  • Centralized governance

  • Fine-grained permissions

  • Data discovery

  • Lineage tracking


SECTION 10 – STREAMING

Topics:

  • Structured Streaming

  • Trigger intervals

  • Watermarking

  • Checkpointing


STREAMING PIPELINES

Use Cases:

  • Kafka ingestion

  • Fraud detection

  • IoT analytics

  • Real-time dashboards


CHECKPOINTING

Purpose:
Fault tolerance.

Critical for:

  • Exactly-once processing

  • Recovery handling


WATERMARKING

Purpose:
Handle late-arriving data.


SECTION 11 – PERFORMANCE OPTIMIZATION

Topics:

  • Partitioning

  • Caching

  • Broadcast joins

  • AQE

  • Data skew

  • Shuffle optimization


PARTITIONING

Critical Topic.

Practice:

  • partitionBy

  • repartition

  • coalesce


BROADCAST JOINS

Purpose:
Optimize small-large joins.


DATA SKEW

Real-Time Problem.

Symptoms:

  • Long-running tasks

  • Uneven executor utilization

Solutions:

  • Salting

  • Repartitioning

  • Broadcast joins


AQE (ADAPTIVE QUERY EXECUTION)

Purpose:
Runtime optimization.


CACHE AND PERSIST

Purpose:
Reuse expensive computations.


SECTION 12 – MEMORY MANAGEMENT

Topics:

  • Driver memory

  • Executor memory

  • Serialization

  • Garbage collection


MEMORY OPTIMIZATION

Learn:

  • Avoid collect()

  • Avoid unnecessary caching

  • Reduce shuffles

  • Optimize partitions

  • Use Delta format


SECTION 13 – REAL-TIME ETL ARCHITECTURE

Topics:

  • Batch ETL

  • Incremental loads

  • CDC

  • SCD

  • Medallion architecture


MEDALLION ARCHITECTURE

Layers:

  • Bronze

  • Silver

  • Gold


BRONZE LAYER

Purpose:
Raw ingestion.


SILVER LAYER

Purpose:
Cleansed and transformed data.


GOLD LAYER

Purpose:
Business-ready analytics.


CDC PIPELINES

Practice:

  • Inserts

  • Updates

  • Deletes

  • Merge logic


SCD TYPE 1 & TYPE 2

Critical DE Topic.

Practice:

  • Historical tracking

  • Delta merge implementation


SECTION 14 – REAL-TIME PROJECT STRUCTURE

Typical Databricks Project Structure:

project/

├── notebooks/
│ ├── bronze_ingestion
│ ├── silver_transformation
│ └── gold_aggregation

├── config/
│ └── config.json

├── src/
│ ├── extract.py
│ ├── transform.py
│ ├── load.py
│ ├── utility.py
│ ├── validations.py
│ └── constants.py

├── logs/
│ └── pipeline.log

├── sql/
│ └── queries.sql

├── tests/
│ └── test_pipeline.py

└── main.py


ENTERPRISE ARCHITECTURE FLOW

API / Kafka / DB / CSV

Databricks Bronze

Validation Layer

Silver Cleansing

Gold Aggregations

Power BI / Reporting


SECTION 15 – MID-LEVEL PROJECTS


PROJECT 1 – SALES ETL PIPELINE

Requirements:

  • Read sales CSV

  • Validate records

  • Remove duplicates

  • Generate KPIs

  • Write Delta tables

Concepts Used:

  • Delta Lake

  • Transformations

  • Aggregations

  • Partitioning


PROJECT 2 – CUSTOMER ANALYTICS PIPELINE

Requirements:

  • Process transactions

  • Generate customer metrics

  • Detect churn

  • Create Gold layer analytics

Concepts Used:

  • Window functions

  • Aggregations

  • Delta merge


PROJECT 3 – CDC INCREMENTAL PIPELINE

Requirements:

  • Process inserts/updates/deletes

  • Maintain history

  • Implement SCD Type 2

Concepts Used:

  • Delta merge

  • CDC

  • Watermarking


PROJECT 4 – REAL-TIME STREAMING PIPELINE

Requirements:

  • Consume Kafka stream

  • Process events

  • Apply watermarking

  • Store streaming Delta tables

Concepts Used:

  • Structured Streaming

  • Checkpointing

  • Delta Lake


PROJECT 5 – CALL CENTER ANALYTICS

Requirements:

  • Process call logs

  • Detect SLA violations

  • Generate agent metrics

  • Build dashboards dataset

Concepts Used:

  • Aggregations

  • Window functions

  • Optimizations


SECTION 16 – DATABRICKS INTERVIEW QUESTIONS

BASIC QUESTIONS

  1. What is Databricks?

  2. What is Lakehouse architecture?

  3. Difference between Data Lake and Lakehouse.

  4. What is Delta Lake?

  5. Difference between parquet and delta.

  6. What are notebooks?

  7. What is DBFS?

  8. Difference between all-purpose and job clusters.

  9. What is lazy evaluation?

  10. Difference between transformation and action.


INTERMEDIATE QUESTIONS

  1. Explain Databricks architecture.

  2. Explain Delta merge.

  3. Explain Z-ordering.

  4. Explain time travel.

  5. Explain broadcast joins.

  6. Explain AQE.

  7. Explain partition pruning.

  8. Explain checkpointing.

  9. Explain Unity Catalog.

  10. Explain medallion architecture.


ADVANCED QUESTIONS

  1. Design enterprise ETL architecture.

  2. Handle billions of records efficiently.

  3. Optimize slow Databricks jobs.

  4. Handle data skew.

  5. Reduce shuffle overhead.

  6. Explain production debugging.

  7. Design incremental pipelines.

  8. Implement SCD Type 2 using Delta Lake.

  9. Design streaming pipelines.

  10. Explain real-time monitoring strategy.


SECTION 17 – 15-DAY EXECUTION PLAN

WEEK 1 – FOUNDATION

Day 1

  • Databricks basics

  • Lakehouse architecture

  • Workspace overview


Day 2

  • Clusters

  • Drivers

  • Executors

  • DBFS


Day 3

  • Notebooks

  • Magic commands

  • Widgets


Day 4

  • DataFrames

  • Transformations

  • Actions


Day 5

  • Read/write CSV

  • JSON

  • Parquet

  • Delta


Day 6

  • Built-in functions

  • UDFs

  • Window functions


Day 7

  • Mini ETL project


WEEK 2 – ADVANCED DATABRICKS

Day 8

  • Delta Lake

  • Merge

  • Time travel


Day 9

  • Workflows

  • Jobs

  • Scheduling


Day 10

  • Unity Catalog

  • Governance

  • Security


Day 11

  • Streaming

  • Watermarking

  • Checkpointing


Day 12

  • Optimization

  • Broadcast joins

  • AQE

  • Skew handling


Day 13

  • CDC

  • Incremental pipelines

  • SCD Type 2


Day 14

  • Mid-level projects


Day 15
FINAL MOCK INTERVIEW + REVISION


REAL-TIME BEST PRACTICES

Always Follow:

  • Use Delta format

  • Avoid collect() on huge datasets

  • Prefer built-in functions over UDFs

  • Optimize joins

  • Avoid unnecessary shuffles

  • Use partition pruning

  • Monitor Spark UI

  • Use autoscaling clusters carefully

  • Use explicit schemas

  • Use modular notebook design

  • Implement logging

  • Handle exceptions properly


MOST IMPORTANT SKILLS FOR SENIOR ENGINEERS

You must become strong in:

  • Databricks architecture

  • Lakehouse understanding

  • Delta Lake optimization

  • Distributed processing

  • ETL design

  • Streaming pipelines

  • Incremental processing

  • Performance tuning

  • Real-time troubleshooting

  • Governance and security

  • Scalability thinking


FINAL INTERVIEW EXPECTATIONS

At 4–10 years experience, interviewers expect:

  • Strong Databricks architecture understanding

  • Delta Lake expertise

  • Real-time ETL implementation knowledge

  • Performance optimization capability

  • Streaming architecture understanding

  • Production troubleshooting mindset

  • Scalable engineering design

  • Governance understanding

  • PySpark + Databricks integration knowledge

They do NOT expect only notebook syntax knowledge.

They expect:

  • Engineering mindset

  • Scalability understanding

  • Optimization thinking

  • Production-level troubleshooting capability

  • Enterprise architecture understanding


END OF DOCUMENT

Comments

Popular posts from this blog

SCD TYPE 2 – INTERVIEW QUESTIONS + MERGE CODE

TIME-SERIES SQL

TIME-BASED SQL QUERIES