The whole manuscript. Even for a speed reader, this would have been a significant investment of her time.
She then, somehow, persuaded the big name editor at the imprint to read the manuscript. He, too, could have said no right after reading the query, or right after finding out how long the book was. Or right after the first paragraph, for that matter.
Instead, the junior editor had this to say, after the usual riff about how the market does not favor long books these days:
I want to stress again how much we both enjoyed the writing. The characters were engrossing, and the worldbuilding fascinating. It's with regret that we are passing on this. We hope you will consider us for other projects.
Rejectomancy is one of the most perilous of the divinatory arts, but I suspect the big name editor may have read the whole manuscript, too. I like to imagine they might have gotten as far as the profit and loss projections before making a final decision.
I went in through the plain old slush pile, unagented, with an unpublishably long manuscript, and now have an ardent invitation to submit future projects to a major editor who's been on my short list for years. And to think that, when I combed over their guidelines for an upper limit on word count and didn't find one, I said out loud to my computer screen, "What are you people thinking? Don't you know you'll get 300,000 word manuscripts from crackpots like me?" The odds were still as much against me as ever, but I figured the Big Book might as well gather virtual dust in the slush reader's email in-box as on my hard drive.
Fortune favors the bold.