What is the significance of Comrade Ogilvy in Orwell's 1984?

Winston Smith's work at the Ministry of Truth is to
rectify or update  the historical record so that it corresponds with previously
published newspaper articles. A case in point is Comrade Ogilvy. He is entirely
Winston's creation, invented to replace Comrade Withers, an Inner Party member whom Big
Brother had awarded with the Order of Conspicuous Merit, Second Class, but who has since
fallen into disgrace and been vaporized. Rather than complicate Big Brother's panegyric,
Winston decides to lift Withers clean out of history and replace him with a fictitious
character, Ogilvy. For this reason he is a flawless patriot and Party member whose 'only
goals in life were the defeat of Eurasia, and the hunting down of enemy spies,
saboteurs, thoughtcriminals, and traitors'. In fact, Ogilvy, who did not exist in the
past, but is called into existence in the present, can be considered a caricature of the
world of Big Brother. And herein lies the significance of Comrade Ogilvy. His world,
where a man can disappear from history, but a fictional character can appear in history
at the stroke of a pen (or Winston's speakwrite!), is above all else stamped with
arbitrariness. In this world, reality is no longer written about.
Rather, it is the written record - at the behest of the Party - which creates
reality.