Excessive memory use in 4.2.1 build 56

If I open a folder that has not previously had thumbnails generated, PL is rapidly consuming memory and never releasing it.

I moved some of my folders from an external drive to my internal SSD and was browsing their contents. I noticed memory pressure rising and then could see the memory used by PL was growing quite fast. If I let it go it consumes all available memory (I only have 16 GB so it doesn’t take long).

I think this was probably the cause of running out of memory on a previous occasion also, when I had the prior version of PL installed (I just installed 4.2.1 today). All files are camera-native DNG files.

I just did some observations. If I let it generate thumbnails offscreen it’s about 0.9GB per minute gets consumed. If I scroll to follow the current generation, that skyrockets to 4.0GB per minute.

By switching back to a folder that already had thumbnails generated, the climb stops, and there is even some small movement downwards, but as soon as I switch to a folder in need of thumbnail generation, up it goes.

A single folder with 566 16 megapixel DNG files is more than enough to eat up all approx 14GB of free memory I have.

What computer are you using? What graphics hardware does it have, and do you know how much video RAM it includes - or if it depends a lot on system RAM?

It’s an M1 MacBook Pro with 16GB of RAM (shared for graphics). I’ve been running PhotoLab on this since December without encountering any out-of-memory errors, but perhaps I have not had to first-index large folders in that time. In any case it seems excessive.

Hi zkarj,

How many images are in these large folders your indexing and what is the average size of the raw files?


OK, real figures here from a new observation.

I open PL and it returns me to an already-indexed folder of 66 images of average size 31 MB. Memory usage is around 1.75 GB at this time.

I then switch to a folder not yet indexed which contains 19 images of around 34 MB average size. Memory goes up to 3.58 GB by the time it has rendered the thumbnails. By my calculations that’s around 96 MB per image — around 3 times the image size.

Finally, I switch to a new unindexed folder of 98 images averaging 31 MB again. Memory climbs to 8.38 GB — this time adding only 49 MB per image, or ~1.6x the RAW size.

Also note the Mac mini I have used for over a year with PL3 & 4 also has 16 GB of RAM and shares it with the GPU, being an Intel integrated one.

There appear to be two issues here:

  1. The large amount of RAM consumed in generating the thumbnails.
  2. The RAM seems never to get released.

This means I need to be careful opening folders, sometimes requiring me to switch back to an already-indexed one to stop the memory grab, then restart the app and reselect the folder to continue indexing.

The folders that are giving me most grief are much larger. I have one folder that has 1320 images in it. Note that this has previously been indexed on one or other of these 16 GB, shared memory Macs. It needs reindexing now because I moved it to another drive.

Paging @sgospodarenko — can this please be raised with the appropriate people?

You should tag @SebinParis or @kettch for this issue.

Svetlana G.

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Sorry for the late reply, we’re working on it.

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I did some work today in PhotoLab and didn’t worry too much about rampant memory use because it was a small folder. When I checked after I had edited one photo it was showing 28 GB used, much of which was swapped to SSD I guess, seeing as there is only physically 16 GB of RAM. I’m not sure why I got the “Run out of application memory” error the other day. I guess stuff that could not be swapped out? I did have another hungry photo app running at that time.