ircd:Ⓜ️ Add slave refresh interface.

include/ircd/m/homeserver.h

@@ -84,6 +84,7 @@ struct ircd::m::homeserver
 	static homeserver *init(const struct opts *);
 	static void fini(homeserver *) noexcept;
 	static bool rehash(homeserver *);
+	static bool refresh(homeserver *);
 };
 
 struct ircd::m::homeserver::key

include/ircd/m/vm/seq.h

@@ -13,6 +13,8 @@
 
 namespace ircd::m::vm::sequence
 {
+	struct refresh;
+
 	extern ctx::dock dock;
 	extern uint64_t retired;      // already written; always monotonic
 	extern uint64_t committed;    // pending write; usually monotonic
@@ -25,3 +27,12 @@ namespace ircd::m::vm::sequence
 	uint64_t max();
 	uint64_t min();
 }
+
+struct ircd::m::vm::sequence::refresh
+{
+	uint64_t database[2] {0, 0};
+	uint64_t retired[2] {0, 0};
+	m::event::id::buf event_id;
+
+	refresh();
+};

matrix/homeserver.cc

@@ -227,6 +227,41 @@ ircd::m::homeserver::rehash(homeserver *const homeserver)
 	return true;
 }
 
+bool
+IRCD_MODULE_EXPORT
+ircd::m::homeserver::refresh(homeserver *const homeserver)
+try
+{
+	if(!homeserver)
+		return false;
+
+	const ctx::uninterruptible::nothrow ui;
+	const vm::sequence::refresh refresh;
+	if(ircd::debugmode)
+		log::logf
+		{
+			log, log::level::DEBUG,
+			"refreshed events[%12lu -> %-12lu] vm[%10lu -> %-10lu] %s",
+			refresh.database[0],
+			refresh.database[1],
+			refresh.retired[0],
+			refresh.retired[1],
+			string_view{refresh.event_id},
+		};
+
+	return true;
+}
+catch(const std::exception &e)
+{
+	log::error
+	{
+		log, "refresh :%s",
+		e.what(),
+	};
+
+	return false;
+}
+
 //
 // homeserver::homeserver::homeserver
 //

matrix/vm_seq.cc

@@ -20,6 +20,34 @@ ircd::m::vm::sequence::committed;
 decltype(ircd::m::vm::sequence::uncommitted)
 ircd::m::vm::sequence::uncommitted;
 
+//
+// refresh::refresh
+//
+
+ircd::m::vm::sequence::refresh::refresh()
+{
+	auto &database
+	{
+		db::database::get("events")
+	};
+
+	if(!database.slave)
+		return;
+
+	this->database[0] = db::sequence(database);
+	this->retired[0] = sequence::retired;
+
+	db::refresh(database);
+	sequence::retired = sequence::get(this->event_id);
+
+	this->database[1] = db::sequence(database);
+	this->retired[1] = sequence::retired;
+}
+
+//
+// tools
+//
+
 uint64_t
 ircd::m::vm::sequence::min()
 {