Copyright	(c) 2024
License	BSD3
Maintainer	maintainer@example.com
Stability	internal
Safe Haskell	None
Language	GHC2021

Hindsight.Store.PostgreSQL.Events.Concurrency

Description

This module implements optimistic concurrency control for the PostgreSQL backend by validating version expectations before event insertion.

Version checks use row-level locking to ensure consistency while minimizing contention between concurrent writers to different streams.

Synopsis

checkVersions :: forall (t :: Type -> Type). Map StreamId (StreamWrite t SomeLatestEvent SQLStore) -> Transaction (Maybe (ConsistencyErrorInfo SQLStore))

Documentation

checkVersions :: forall (t :: Type -> Type). Map StreamId (StreamWrite t SomeLatestEvent SQLStore) -> Transaction (Maybe (ConsistencyErrorInfo SQLStore)) Source #

Validate version expectations for all event batches.

Acquires row-level locks on affected streams and checks that each stream's current version matches the expected version. Returns Nothing if all checks pass, or details of any mismatches.