Modulevortex-journal-0.1.0GHC2024

Vortex.Journal.Concurrent

Appending at a version: optimistic concurrency. A writer decides against the log as it stood at some version and asks to append there. If nothing recorded since touches a token its operations touch, the order does not matter (independent operations commute) and the append goes through; otherwise it is a conflict, and the writer decides again.

1 type
2 values

Packagevortex-journal-0.1.0
Exports3
LanguageGHC2024
LicenceMIT
SourceConcurrent.hs

datadata Conflict op ans tok

Why an append at a version did not go through.

Constructors

Dependent [(Answered op ans, Answered op ans)]
pairs of an operation recorded since and one of the append that touch a token in common
UnknownVersion Version
the version is before the log's base or after its end
Disabled (Refusal op ans tok)
an operation of the append is not enabled where it would land

Instances2Eq, Show

(Eq ans, Eq tok, Eq op) => Eq (Conflict op ans tok)Defined in vortex-journal-0.1.0 · Vortex.Journal.Concurrent
(Show ans, Show tok, Show op) => Show (Conflict op ans tok)Defined in vortex-journal-0.1.0 · Vortex.Journal.Concurrent

valuedependent

:: Ord tok
=> Net op ans tok
-> [Answered op ans]
-> [Answered op ans]
-> Bool

Is some operation of the second list dependent on (touching a token of) some operation of the first?

valueappendAt

:: Ord tok
=> Net op ans tok
-> Log op ans tok
-> Version
-> [Answered op ans]
-> Either (Conflict op ans tok) (Log op ans tok)

Append operations decided at a version. At the log's own version this is a plain append; behind it, the append goes through only if it is independent of everything recorded since.