Function begin_replication_step

src/backend/replication/logical/worker.c:289–303

* Begin one step (one INSERT, UPDATE, etc) of a replication transaction. * * Start a transaction, if this is the first step (else we keep using the * existing transaction). * Also provide a global snapshot and ensure we run in ApplyMessageContext. */

 * Also provide a global snapshot and ensure we run in ApplyMessageContext.
 */
static void
begin_replication_step(void)
{
	SetCurrentStatementStartTimestamp();

	if (!IsTransactionState())
	{
		StartTransactionCommand();
		maybe_reread_subscription();
	}

	PushActiveSnapshot(GetTransactionSnapshot());

	MemoryContextSwitchTo(ApplyMessageContext);
}

/*
 * Finish up one step of a replication transaction.