transcript
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Database indexes are one of the most important tools for improving query performance - but there are many different types, and the differences between them are not always obvious.
In this episode, I explain how indexes work, what's their benefits and drawbacks, and I go through the main index types and concepts: B-tree and B+ tree indexes, dense and sparse indexes, bitmap and hash indexes, clustered and non-clustered indexes, composite and covering indexes, as well as duplicate and redundant indexes.
There also details about why column order matters in composite indexes and how an index-only scan can avoid reading the table altogether - just as an example.
This is a solid and practical high-level overview for data engineers who want to better understand indexes for both everyday work and technical interviews.
