P: Adding to/Creation of a new Target collection takes minutes unless Sync is paused

Same issues for me. Catalog with 500k images, 400k synchronized. All was working fine before sync mechanism changed (on another platform?) and the conversion on my catalog. I think issues are related to the structure of the catalog (bug in the database?) . it work with a new catalog but i need several days/weeks to import old one. And I lost too much information with sync. collections . This is a nightmare ..

My RAM usage is "kind of" withing normal - 11-12Gb after several hours syncing

Same here, Lightroom Classic is still unusable. 

However, right now I've noticed that as soon as the synchronization starts, RAM fills slowly up.

With sync deactivated Lightroom uses between 2GB and 5GB of the 32GB RAM of my Mac and works as intended.

When I start the synchronization Lightroom tries to reserve more and more memory. 

After an hour it still has not uploaded any photos, but tries to use 85GB RAM....which just does not work.

Lightroom Classic becomes unusable at this point.

Strangely enough, this continues even if I pause sync again.

The bug is still rampant and makes my Lightroom impossible to use, as of 21 Septermber 2024! I have also noticed that if the sync queue is above 10 thousand images, the lags become atrocious! 

Hey Rikk,

Despite the fact that  you've now been forced to accept  that my thread which you worked so hard to dumb down and downgrade and silence is indeed indicative of an issue,  you are still continuing with your old tricks!

You merged it with the bug report which only deals with specific "Lag in new target collection creation"  and was filed September 15. My thread was much more broad and descriptive, it reflected the nature of the issue more fully, since it is not limited to only Collections, and it was initially posted in early July!

May I observe here that your Process Version update lag (which you were able to reproduce, halliluja!)  is just one of the dozen possible lags happening as a result of this bug. Similarly,  updating the Loop preview can lag (after editing in Develop module, switch back to Loop and the preview is not updated to reflect edits), the apply auto tone corrections command lags, export image lags, create new collection lags, add image to collection, apply AI masked presets, and several others. What is interesting, is the fact that other commands, like making edits with sliders, etc - all work fine.

So the lags are present only within a specific set of commands (that somehow got intertwined with the background sync processor thread which is only allowed a very limited CPU resource). Please update the title and issue descriptoin to reflect all the above,  if you are indeed interested in helping the community to fix the issue, and not only in exercising you moderation powers by locking, merging and editing titles in a way that makes it very hard to find the issue or understand its nature (senior management is now watching you, so tread carefully)!

Do you by any chance have sync and automatic xmp writes turned on. There are some reports of a bug that leads to extreme slowdowns if both of these are on even when doing simple stuff such as adding to a collection. Try turning off automatic xmp writes and pausing sync. 

Thas all started when they changed the sync mechanism (13.3 I think) , and has been living hell since then. I try to create new collection - have to wait 2 minutes for it to appear in the list. I hit B to add a picture to current target collection - have to wait 2 minutes for it to register in the collection. Apply Portrait effect (auto masking) - have to wait 2 minutes for it to appear. The bug is intermittent - sometimes all works fine (rare occasions) - and the AI masks themselve take only 1-2 sec to calculate on my M2 MaX Macbook Pro.  But when it lags, oh boy!  the lags and freezes are unbearable, they happen with many library operations, especially related to collections creations, adding pics to collections and enabling/disabling cloud sync for a given collection - that all makes Lightroom barely usable. 
the lags are all tied to the cloud sync operation - when there are images in the sync queue many operations lag unbearably, including quitting the app. 

P.S. whats with the "topics" that this forum suggest to select "to help users find my post" and selection is FROM THREE topics - macOS, Windows and SDK! WHere are other topics???