Materialises finalised registry events from the hot-store changelog into the Registry database, using an independent change_seq cursor persisted in the registry DB. Implements events::IEventProjector so it can be driven by the existing EventsRuntime projection loop. More...

#include <registry_projector.hpp>

Inheritance diagram for dcn::registry::RegistryProjector:

Public Member Functions
	RegistryProjector (events::SQLiteHotStore &store, Registry &registry, const asio::strand< asio::io_context::executor_type > &write_strand, events::ProjectorRetryConfig retry={})
std::string_view	id () const override
std::int64_t	cursor () const override
asio::awaitable< std::size_t >	projectBatch (std::size_t limit, std::int64_t now_ms) override
Public Member Functions inherited from dcn::events::IEventProjector
virtual	~IEventProjector ()=default

Detailed Description

Materialises finalised registry events from the hot-store changelog into the Registry database, using an independent change_seq cursor persisted in the registry DB. Implements events::IEventProjector so it can be driven by the existing EventsRuntime projection loop.

Cursor policy:

cursor is loaded from the registry DB at construction and persisted after each batch (only if at least one row was consumed or skipped).
non-finalized rows (observed/safe/removed) are skipped; their change_seq is still advanced past because they will re-surface with a higher change_seq when they reach "finalized".

Failure policy (per _materializeOne):

success / already present → cursor advanced.
failure (undecodable log, divergence, add rejection) → cursor is left before the row and the row is retried on subsequent projectBatch passes, so transient failures (e.g. busy registry DB) heal on their own. After ProjectorRetryConfig::max_attempts consecutive failing passes the row is dead-lettered (REGISTRY_DEAD_LETTER_BIT in the hot store) and the cursor advances past it: a permanently parked cursor would freeze the prune watermark for every projector and grow the hot store without bound. Dead-lettered rows are exempt from pruning, so no chain event data is lost; a periodic idle-time sweep (ProjectorRetryConfig::sweep_interval_ms) retries them and clears the bit once materialization succeeds. If the dead-letter mark itself cannot be written, the cursor stays parked.

Constructor & Destructor Documentation

◆ RegistryProjector()

dcn::registry::RegistryProjector::RegistryProjector	(	events::SQLiteHotStore &	store,
		Registry &	registry,
		const asio::strand< asio::io_context::executor_type > &	write_strand,
		events::ProjectorRetryConfig	retry = {} )