Catalogs Preview Cache Size

[BobT]

Lightroom Version Number

14.0.1

Operating System

1. Windows 11

In Catalog Settings>Previews>Preview Cache, it states the total size as 5GB. Further down, in "Limit Preview Cache Size", if that is set to say 10GB, the preview cache size above, stays at 5GB. Am I misunderstanding something?
Also, if using the other option "Automatically Discard 1:1 Previews" after 30 days or whatever, what happens if the cache is full before that? I can guess but it's not stated.

 

[Johan Elzenga]

The 5GB is the actual size of the previews cache right now. You ask Lightroom to start deleting previews if the cache size gets to 10GB. Obviously that does not change the current size, because that is only 5GB. If you use ’Discard 1:1 previews after 30 days’, then Lightroom will not do anything when the cache size gets to 10GB.

 

[BobT]

The 5GB is the actual size of the previews cache right now. You ask Lightroom to start deleting previews if the cache size gets to 10GB. Obviously that does not change the current size, because that is only 5GB. If you use ’Discard 1:1 previews after 30 days’, then Lightroom will not do anything when the cache size gets to 10GB.

The thing is that the 5GB preview cache size figure seems to be fixed. As a test, I reduced the max. preview cache size to 3GB. I got the warning that some previews will be lost, but went ahead anyway, closed LrC, waited a while, opened LrC. The preview cache size at the top remained at 5GB and the max. preview cache size remained at the 3GB I entered before. It doesn't make a lot of sense.

 

[Johan Elzenga]

The thing is that the 5GB preview cache size figure seems to be fixed. As a test, I reduced the max. preview cache size to 3GB. I got the warning that some previews will be lost, but went ahead anyway, closed LrC, waited a while, opened LrC. The preview cache size at the top remained at 5GB and the max. preview cache size remained at the 3GB I entered before. It doesn't make a lot of sense.

This is a known issue. It seems the purging does not work very well at this moment.

 

[clee01l]

The thing is that the 5GB preview cache size figure seems to be fixed. As a test, I reduced the max. preview cache size to 3GB. I got the warning that some previews will be lost, but went ahead anyway, closed LrC, waited a while, opened LrC. The preview cache size at the top remained at 5GB and the max. preview cache size remained at the 3GB I entered before. It doesn't make a lot of sense.

I don't think the reduction in size occurs immediately. Initially my Preview cache was set to 50GB. I increased that to 100GB. It was not until my Total Size reached 103GB did I get a pop up message (in yellow) that I had reached the limit and did I want to increase it. I'm not sure there is an issue. as Johan says or if the process has some over limit (3GB perhaps?) that has to be reached before the Cache is reduced? If the over limit that triggers the action is 3GB , as mine indicates, you would need to hit a total size of 6GB before you get the message. Alternately the over limit could be 3%, in which case, you would see your pop up messagethe next time LrC built a preview.

 

[Johan Elzenga]

https://community.adobe.com/t5/ligh...-size-taking-too-long-to-purge/idi-p/14957931

 

[clee01l]

https://community.adobe.com/t5/ligh...-size-taking-too-long-to-purge/idi-p/14957931

I have no problem with this being under review as a possible bug, I am just saying that the process may allow some size over the limit before producing the warning message. Those in that thread don't appear to be getting the warning message that I get. And this may be a Windows bug that I don't see in MacOS version of LrC

 

[Johan Elzenga]

I haven’t tried it myself, but what I understand is that even if you do get that message, the purging does not actually take place.