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Main Authors: Zhang, Jianshun, Wang, Fang, Qiu, Sheng, Wang, Yi, Ou, Jiaxin, Huang, Junxun, Li, Baoquan, Fang, Peng, Feng, Dan
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2508.13909
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author Zhang, Jianshun
Wang, Fang
Qiu, Sheng
Wang, Yi
Ou, Jiaxin
Huang, Junxun
Li, Baoquan
Fang, Peng
Feng, Dan
author_facet Zhang, Jianshun
Wang, Fang
Qiu, Sheng
Wang, Yi
Ou, Jiaxin
Huang, Junxun
Li, Baoquan
Fang, Peng
Feng, Dan
contents Key-Value Stores (KVS) implemented with log-structured merge-tree (LSM-tree) have gained widespread acceptance in storage systems. Nonetheless, a significant challenge arises in the form of high write amplification due to the compaction process. While KV-separated LSM-trees successfully tackle this issue, they also bring about substantial space amplification problems, a concern that cannot be overlooked in cost-sensitive scenarios. Garbage collection (GC) holds significant promise for space amplification reduction, yet existing GC strategies often fall short in optimization performance, lacking thorough consideration of workload characteristics. Additionally, current KV-separated LSM-trees also ignore the adverse effect of the space amplification in the index LSM-tree. In this paper, we systematically analyze the sources of space amplification of KV-separated LSM-trees and introduce Scavenger, which achieves a better trade-off between performance and space amplification. Scavenger initially proposes an I/O-efficient garbage collection scheme to reduce I/O overhead and incorporates a space-aware compaction strategy based on compensated size to minimize the space amplification of index LSM-trees. Extensive experiments show that Scavenger significantly improves write performance and achieves lower space amplification than other KV-separated LSM-trees (including BlobDB, Titan, and TerarkDB).
format Preprint
id arxiv_https___arxiv_org_abs_2508_13909
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Scavenger: Better Space-Time Trade-Offs for Key-Value Separated LSM-trees
Zhang, Jianshun
Wang, Fang
Qiu, Sheng
Wang, Yi
Ou, Jiaxin
Huang, Junxun
Li, Baoquan
Fang, Peng
Feng, Dan
Databases
Key-Value Stores (KVS) implemented with log-structured merge-tree (LSM-tree) have gained widespread acceptance in storage systems. Nonetheless, a significant challenge arises in the form of high write amplification due to the compaction process. While KV-separated LSM-trees successfully tackle this issue, they also bring about substantial space amplification problems, a concern that cannot be overlooked in cost-sensitive scenarios. Garbage collection (GC) holds significant promise for space amplification reduction, yet existing GC strategies often fall short in optimization performance, lacking thorough consideration of workload characteristics. Additionally, current KV-separated LSM-trees also ignore the adverse effect of the space amplification in the index LSM-tree. In this paper, we systematically analyze the sources of space amplification of KV-separated LSM-trees and introduce Scavenger, which achieves a better trade-off between performance and space amplification. Scavenger initially proposes an I/O-efficient garbage collection scheme to reduce I/O overhead and incorporates a space-aware compaction strategy based on compensated size to minimize the space amplification of index LSM-trees. Extensive experiments show that Scavenger significantly improves write performance and achieves lower space amplification than other KV-separated LSM-trees (including BlobDB, Titan, and TerarkDB).
title Scavenger: Better Space-Time Trade-Offs for Key-Value Separated LSM-trees
topic Databases
url https://arxiv.org/abs/2508.13909