Unit of Work

In one line: the unit of durability — it groups one or more transactions into a single flush cycle and decides, via its DurabilityMode, when their commits become crash-safe.

Typhon splits "what's atomic" from "what's durable". A transaction is atomic and isolated; a UnitOfWork is the durability boundary that wraps it. Durability is a batched, cross-cutting concern — one fsync can make many transactions durable at once — so it lives one level up from the transaction.

A committed transaction is visible immediately, but only becomes durable when its UoW flushes — on the schedule set by its DurabilityMode. Under the runtime, there is exactly one UoW per tick.

How it relates

• Transaction — what a UoW contains; visibility is the transaction's job, durability is the UoW's.
• Durability — mode & discipline — the UoW's DurabilityMode is the when-does-the-WAL-flush dial.
• The tick — the runtime opens one UoW per tick and flushes it at tick end.
• Snapshot isolation — visibility advances independently of the UoW's flush.

In the API

• UnitOfWork — the type itself; CreateTransaction(...), Flush() / FlushAsync().
• DatabaseEngine — CreateUnitOfWork(DurabilityMode).
• DurabilityMode — the flush-timing enum set at UoW creation.

Learn & use

• Narrative: Guide ch.3 §1 — two layers
• Reference: Isolation & durability cheat sheet
• Feature detail: Unit of Work · durability modes