Very large Collections / ~sets slow down Lightroom Classic?

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Active Member
Nov 28, 2010
The Netherlands
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Operating System
  1. macOS 11 Big Sur
My main Lr machine is still a 2013 MacBook Pro 15" Retina w/ 16GB RAM. My "private" catalog holds 150,000 images and tends to be quite slow, whereas a fresh catalog is still reasonably responsive. I always thought that my 150,000 images catalog was slow because there are so many images.

Then, while discussing config options on a Mac users forum, a contributor comes up with an interesting observation about collections. He says when his collection goes over say 15,000 images, and he has several of those in a collection set, at some point Lr will slow down. Then when he moves some of his collections to a different Collection Set, he's back up to speed. His guess is Adobe reserves a predefined block of memory for a collection set and then when that memory is full, trouble starts.

My question here is have you ever heard of this?

As soon as I get back home I will try to experiment with this myself. I have a bunch of smart collections, all in one collection set, containing my workflow, i.e. which images don't have flags, don't have ratings, no keywords and so on. For statistics I also have smart collections counting finished images, unfinished images etc. These smart collections may contain 50,000 or more images each, and they're all in the same collection set.


crossposted on Adobe forums
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