What does this research mean for the field?

Git-like database branching can be implemented directly on LSM-tree storage using page-level copy-on-write with Delta SSTables, enabling sub-millisecond branch creation and supporting multiple merge strategies with SERIALIZABLE isolation. Novelty: ClaimNovelty.METHODOLOGICAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

The aim is to implement a git-like branching mechanism on LSM-tree storage using Delta SSTables.

March 28, 2026Open Access

LSN-Based Copy-on-Write Database Branching on LSM-Tree Storage with Delta SSTables and Multi-Strategy Merge

Key Points

The aim is to implement a git-like branching mechanism on LSM-tree storage using Delta SSTables.
Implemented page-level copy-on-write using Delta SSTables.
Created branches as metadata-only operations with sub-millisecond latency.
Supported seven merge strategies for conflict resolution.
Maintained independent MVCC snapshots for each branch.
Branches created in under a millisecond.
Efficient read operations through a four-layer hierarchy.
Supported complex merge strategies, including conflict detection.

Abstract

We describe an implementation of git-like database branching on top of LSM-tree (Log-Structured Merge-tree) storage using RocksDB. Unlike existing database branching implementations that use custom storage formats (Dolt’s prolly trees), distributed storage layers (Neon), or block-level snapshots (Simplyblock Vela), our approach mplements page-level copy-on-write using Delta SSTables within the LSM-tree architecture. Branches are created in sub-millisecond time as metadata-only operations (256bytes). Read operations traverse a four-layer hierarchy: branch memtable, branch Delta SSTables, parent Delta SSTables, and shared SSTables. The system supports seven merge strategies (Ours, Theirs,Manual, RuleBased, LastWriteWins, Custom UDF, Abort) with three-way merge conflict detection. Each branch maintains independent MVCC snapshots with SERIALIZABLE isolation. This disclosure establishes prior art for LSM-tree-specific database branching with Delta SSTables.

LSN-Based Copy-on-Write Database Branching on LSM-Tree Storage with Delta SSTables and Multi-Strategy Merge

Key Points

Abstract

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