
Spring Core Principles - Basic Edition
yh
$68.20
Basic / Spring, oop
5.0
(4,886)
Spring beginners can grasp core principles and solidify basics via examples.
Basic
Spring, oop
"A query that ran perfectly during development suddenly slows down as data accumulates." At such times, the mark of a truly skilled developer is identifying the root cause based on solid evidence rather than guesswork, and optimizing a 30-second query down to 0.1 seconds. Master the core principles of database performance—from execution plans, indexes, and optimizers to joins and sorting—using millions of rows of real-world data. Elevate your skills and become a top-tier developer capable of independently analyzing and resolving slow queries in production environments.
230 learners are taking this course
Level Intermediate
Course period Unlimited
The ability to read an execution plan and independently diagnose the cause of a slow query.
The ability to independently design indexes tailored to specific situations.
Real-World Experience in Optimizing Queries by 10x to 100x Across Millions of Data Records
Understanding Database Internals Beyond Indexes
Kim Young-han's Practical Database
3 million members, 5 million products
The service is growing day by day, but
is it getting slower and slower?!
Amidst the massive volume of data, the queries that have become bottlenecks...
How can we solve this?
If you've hit a fundamental limit in database performance
Accurate diagnosis and tuning strategy is
needed.
That is why we have prepared
The final stage of database learning is,
ultimately, performance.
Once you learn to write queries, everyone hits the same wall at some point.
'I know I wrote it right, so why is it so slow?'
That's exactly why we made performance optimization the final topic of the database roadmap.
Once you see with your own eyes how queries are actually executed and why indexes are so fast,
only then can you say you properly handle databases.
With a solid, practical guide, we'll help you complete the final step of your database journey.
By taking this course,
I created an index, but why does the optimizer ignore it?
Even when it hits the index perfectly, why is it still slow?
EXPLAIN results, where should I start reading?
Can a single join order really turn 0.01 seconds into 22 seconds?
Why does it suddenly slow down just by adding ORDER BY?
As you turn the pages further back, why does it get slower and slower?
POINT 1
Discover the true reasons behind slow queries and resolve them by applying fundamental principles.
STEP 01
Understand how queries are executed internally within the database, and accurately diagnose the root causes of performance bottlenecks using EXPLAIN and EXPLAIN ANALYZE.
STEP 02
Understand why indexes are fast through the B+Tree structure, and identify why they can still be slow even when used, to design composite and covering indexes.
STEP 03
Learn how to resolve performance issues for each query type, from retrieval and search to joins, sorting, paging, and grouping.
POINT 2
Imagine you've just joined a rapidly growing e-commerce company.
This course is designed to help you build real-world expertise
by tackling various performance issues you'll encounter in the field.
4 Hands-On Tuning Exercises: Solve Problems Directly Using the Principles You've Learned
Tuning 01 · Execution Plan
🛒 Admin Order Inquiry
Quickly retrieve only the necessary data using a composite index
Diagnose the full scan of 10 million rows using EXPLAIN, and rewrite the query to read only the necessary rows.
Tuning 02 · Sorting
🔍 Product Search
Eliminate the sorting operation itself by using index sorting
We eliminate the filesort that re-sorts the rows for every ORDER BY by using index sorting.
Tuning 03 · Joins
📊 Order Statistics by Member
Covering index to retrieve all data in a single pass without revisiting the original table
Eliminate the bottleneck of revisiting the original table on every join by using a covering index.
Tuning 04 · Grouping
⭐ Review Rating Aggregation
Aggregates immediately without a temporary table using index sorting
Eliminates the temporary table created by GROUP BY using index sorting, enabling direct aggregation.
Roadmap
As a continuation of Kim Young-han's Practical Database Roadmap, this course covers how to diagnose performance issues encountered in large-scale services using execution plans and resolve them with indexes.
📚 Roadmap Structure
📺 Roadmap Study Guide
Who is this course right for?
Job seekers and students preparing for careers in the IT field
A backend developer who encountered a slow query in a live service but is at a complete loss as to where to begin troubleshooting.
A developer who is comfortable with feature development using SQL, but lacks confidence when faced with performance issues.
Aspiring Database Administrator (DBA)
Need to know before starting?
Kim Young-han's Practical Database Fundamentals
Inflearn Verified
604,306
Learners
42,428
Reviews
9,115
Answers
5.0
Rating
27
Courses
Educator
Before: Technical Director at Woowa Bros, Kakao, SK Planet
Author: Java ORM Standard JPA Programming
My goal is to provide education so that you can become a truly practical and competent developer.
EO Interview Video
The Life of Korea's Top Developer Instructor Young-han Kim [Part 1]
The Life of Younghan Kim, Korea's Top Developer Instructor [Part 2]
Gaebalbadak - A Country Youth Becomes the King of Development
Q&A Commemorating Inflearn Reaching 200,000 Users for the First Time
Q&A Commemorating Inflearn Reaching 300,000 Users for the First Time
All
104 lectures ∙ (21hr 10min)
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