hesela.devRead amplification
Read amplification expresses storage-read work per logical read request or per useful byte returned, under an explicitly stated accounting convention.
RocksDB's tuning guide uses physical disk reads per query. Candidate sorted runs, cache lookups, device I/O operations and bytes read are not interchangeable counters. [1] A Bloom-filter model's expected probes per absent lookup is not measured physical I/O: cache hits can eliminate device reads, while cold metadata can add reads. Separate successful lookups, absent lookups and scans, and separate foreground-query reads from compaction reads. A bytes-read/bytes-returned ratio is undefined for an absent query returning zero bytes; report reads per query instead. [2]
Relations
- related
- lsm-tree, leveled-compaction, tiered-compaction, bloom-filter, database-write-amplification