Database / RocksDB Basics Interview Questions
What is Write Amplification?
Write amplification is the ratio between the total amount of data actually written to physical storage and the amount of data the application logically intended to write.
- Arises because a single logical write can end up being rewritten multiple times as it moves through compaction across levels
- Higher write amplification means more wear on storage hardware and more background I/O competing with the application's own workload
- Different compaction styles trade write amplification against read and space amplification differently
This is one of the three core trade-offs, alongside read and space amplification, that shapes almost every tuning decision made when configuring an LSM-tree-based store like RocksDB.
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