I recently came across a reference manual for an SoC that came in at over 24,000 pages - a new personal record. The tools for working with such large PDFs generally suck.

I'd be so happy with a 24,000 page PDF, cause then at least you know where too look, and you can the search tool. I programme Siemens hardware and the docs I need are spread out over many tens of PDFs (of 100-1500 pages). I haven't found a proper tool than can let me search and view all this documentation properly. Best I found is ripgrep with some PDF extension to search which document I need, and then use SumatraPDF for finding the right page... ughh

Use Agent Ransack (free) or better, File Locator Pro ($69) from Mythicsoft. Both include comprehensive PDF text searching. AR includes the full functionality of FLP as a 30 day trial. Money you'll recover many times over and a product you'll be using for the rest of your life. https://www.mythicsoft.com/

How about joining all the PDFs together and doing ctrl-F? Sounds like it could save you the grep step.

In the particular case of Siemens, they already did that for you.

(Migrating from S7-300 PLCs to the current S7-1500 range, I found the complete documentation package for the 1500 universe in one whopper of a pdf. Just north of 11,000 pages IIRC.)

I shared the OPs frustration when working on the S7-300, though. The docs are excellent, there's just so many of them...

Acrobat reader used to let you search all PDFs in a directory; not sure if it still lets you do that.

Use Recoll, a desktop full text search tool which uses Xapian as the backend.

Evince on Linux is by far the best program I've found for reading large PDFs. It's worth the trouble to setup a VM or WSL just to run Evince if you're not natively on Linux.

Another terrific option is Okular. It actually has a setting to reduce memory usage on large PDF files by not prerendering pages that are not being viewed.

Eek, Okular. The one time I resorted to downgrading a package in 20+ years of using Linux. A few years back, someone drank too much design Kool-Aid and introduced smooth scrolling without making it optional. That did not get a very good reception from everyone, as browsing 20,000-page reference manuals with buttery smooth scrolling is, literally, dizzying.

I don't know if it ever got fixed. I stopped using Linux around the time when it was introduced, and having had to revert to using xpdf for browsing large PDFs like it was 1994 again was part of why I ragequit :-(.

I've never opened a 20,000 page document, but I've opened documents of several hundred pages with no noticeable issues. Pressing either Space or PgDown instantly moves the page down, no scrolling animation. The option still does not exist, but it seems that the feature doesn't exist either.

IIRC the eventual fix was to have it respect the global compositor settings, so if you have animation speed set to instant, while it does actually smooth scroll, it does so instantly. However, when it was introduced, it did not; for similar reasons (i.e. I don't like nausea), I had animations disabled, but Okular did its thing, and slowly.

It took some time for it to land though and not without the kind of discussions that you see on the Gnome bug tracker. It was pretty disheartening.

I've actually been using an (ancient) build of Evince for Windows [0] for quite some time now.

[0] https://www.fosshub.com/Evince.html

I've never had to read a large PDFs (probably, ~400 pages) but what's so great about Evince? Is it just speed or is it because of it's features?

One feature I really like is that if you hover over a link Evince previews the target of the link in a little box. Perfect for "see Table X on page Y"

I use Evince on Linux and PDF Expert on MacOS. They both do okay, but neither does search indexing, so searching goes irritatingly slow. Also neither support the public key encrypted PDFs that a certain SoC vendor likes to give me.

Sumatra PDF on windows is very fast.

I like it so much in fact that I've been looking for a linux alternative and haven't been satisfied yet. I will try evince though.

Preview.app used to be very good for large pdfs, back in what I suddenly realize must be considered "the early days" of OS X, maybe 8 years ago.

Now? Eh, Firefox. If that doesn't work, well, find an old Mac which hasn't been "upgraded" I guess.

SumatraPDF works far better than Firefox for me for service manuals (half a gigabyte or so usually). It doesn't have fancy features but it's very quick to load and render.

It seems like any PDF viewer that runs in a browser just can't handle big documents and often will be terribly slow on even medium sized ones. I always have to use standalone viewers to get them to load.

I usually use SumatraPDF on Windows, it's super lightweight, fast, and can handle large documents. However, I never tried it with more than 1500 pages or so. No idea if it would survive a 24k pages PDF, would be a good test...