Mastering Database Performance and Trade offs
Stop Adding Indexes Blindly! How Database Indexes Actually Work
Ever added an index to fix a slow query, only to find that six months later your database writes are crawling?
You aren’t alone. While indexes can drop a query's response time from 4.2 seconds to 3 milliseconds, they aren't a "free" performance boost.
In this video, we go under the hood to understand the mechanics of indexing so you can build faster, more efficient databases.
In this video, we cover:
The Full Table Scan Problem: Why your API response times spike during peak traffic and how a linear scan fails as your data grows.
B-Trees (and B+ Trees) Explained: A deep dive into the foundational data structure used by PostgreSQL, MySQL, SQL Server, and Oracle.
Learn how a B-tree turns 10 million rows into just three or four disk reads.
The Phone Book Analogy: Why column order in a composite index is the single most important design decision you’ll make.
We explain the "leftmost prefix rule" and why skipping a column can break your index's utility.
Optimizing Composite Indexes: Why you should always put equality conditions first and range conditions last to keep your scan range as tight as possible.
Covering Indexes & Include Clauses: How to eliminate expensive "bookmark lookups" or "heap fetches" by storing all the data a query needs directly in the index leaf nodes.
The Hidden Cost of "Index Everything": Every index is a tax on your writes.
We discuss how 12 different indexes can turn one application insert into 13 separate database writes, killing your performance.
When the Database Ignores Your Index: Why the query planner might choose a sequential scan even if an index exists, especially with low cardinality columns.
Maintenance & Cleanup: How to use tools like EXPLAIN ANALYZE and system views (like pg_stat_user_indexes) to find and drop indexes that aren't earning their keep.
Stop guessing and start measuring. The difference between a fast database and a slow one isn't just hardware—it’s whether the people running it truly understand their indexes.
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