Mastering Data Storage in DB: The Battle of LSM Trees vs B-Trees

A Side-by-Side Showdown of LSM Trees vs B-Trees

Siddharth Gangwar
BloggingTimes
3 min readFeb 10, 2023

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When it comes to data storage and retrieval, two of the most popular indexing structures used in storage engines are Log-Structured Merge Trees (LSM Trees) and B-Trees. Both structures have their own strengths and weaknesses, and the choice of which one to use often depends on the specific use case.

B-Trees

The traditional indexing structure used in many relational databases. They are balanced trees that maintain a logarithmic time complexity for inserts, updates, and deletes, making them well-suited for use cases where data is updated frequently. B-Trees are optimized for storage on disk, and they are commonly used in storage engines such as MySQL, PostgreSQL, and Oracle.

LSM Trees

On the other hand, were designed specifically to address the limitations of B-Trees when working with large amounts of write-intensive data. Instead of updating the data in place, LSM Trees write new data to a series of append-only data structures called SSTables. This allows for more efficient use of disk space and reduces the overhead of indexing updates, making LSM Trees ideal for use cases where write-heavy workloads are the norm. LSM Trees are commonly used in storage engines such as Cassandra and LevelDB.

What books say ?

When it comes to read performance, B-Trees are generally faster than LSM Trees, as they allow for direct access to the data in a single disk seek. LSM Trees, on the other hand, require merging the data from multiple SSTables to return the results of a query, which can result in slower read performance. However, LSM Trees are designed to use compaction to improve read performance over time, by periodically merging SSTables into larger, more efficient structures.

Side by side Comparison

In summary, LSM Trees are optimized for write-intensive workloads, while B-Trees are optimized for read-intensive workloads. The choice between the two will depend on the specific requirements of your use case and the balance between write and read performance that you need to achieve.

Conclusion

Both LSM Trees and B-Trees have their place in the world of data storage and retrieval. B-Trees are well-suited for use cases where updates are frequent and data is relatively small, while LSM Trees are designed to handle large amounts of write-intensive data. When choosing between the two, it’s important to consider the specific requirements of your use case and choose the structure that best fits your needs.

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Siddharth Gangwar
BloggingTimes

I'm a problem solver at heart. Whether the challenge is big or small, I'm passionate about finding efficient solutions to any type of problem.