@md999 I have so far documented a variety of potential solutions in the forum but with no response from other forum members or you, which is a little disappointing?!
I believe that the issue with large directories is only relevant insofar as when it is not possible to pass a file (preferably more than one) to PL5 it then becomes necessary to open the entire directory in PL5 with all the problems that can cause , i.e. the time taken to open all the thumbnails in the directory which is further exacerbated because PL5 renders and re-renders the thumbnails with PL5 edits (and does this every time that the directory is opened and re-opened and traversed and …).
With respect to improving directory opening I believe that this could be improved if PL5 abandoned its current thumbnail caching scheme and replaced it with a full time SQLite database for the thumbnails, i.e. “persist” the thumbnails.
This would be complicated with PL5 because as photos are edited their thumbnail would need to be updated in the SQLite thumbnail database and worse, if a “rogue” DOP or DOPs were added to a directory the thumbnails would need to re-rendered in the light of these changes and even worse new DOPs being added might cause the introduction of Virtual Copy thumbnails which would need to be added to the thumbnail database and any other complications that you can think of. But it would improve general speed in PL5 and reduce the amount of spinning icons (if all the ramifications can be satisfactorily resolved)!
However, the database would be large and the whole thing becomes extremely complicated when thumbnail sizes as changed and what happens when the main PL5 database is destroyed (in my case mostly deliberately)? and…
I have a DigiKam system only up to date as of early 2021 which is now updating itself automatically so I will get a better idea of the issues of thumbnails in a SQLite database from that.
Failing such a radical new feature the only other alternative is to never browse the big directories in PL5 but do that browsing elsewhere and submit requests for editing directly to PL5. Now the problems really start because while some programs play nicely others do not or (vice versa) PL5 plays well with some programs but not with others, whichever way you want to present the problem, i.e. try to get your other supplier to change or get DxO to change or find a product that does all that you want with respect to management and searching but including (I would suggest) passing one or many photos from one or many directories to PL5 in a single submission!?
Some programs when passing a group of files will be greeted by PL5 starting to scan the entire directory, this also seems to happen with Photo Mechanic when drag and drop is used (at least in my tests).
Some programs when passing a group will actually have only one opened by PL5, better than nothing but …
Others packages will cause all the photos to be opened but effectively in multiple windows, in PL5 this manifests itself as one entry for every photo in the group with each photo represented as a single item in the ‘External selections’, they are all there - well sort of! With PM and PL5 if PL5 is shut down only one photo will make it to PL5 but with PL5 already running all the photos will be available but as separate selections making it impossible to compare and contrast etc. in PL5.
XnViewMP and Photo Supreme seem to “play” nicely and pass the list of files in a manner that results in PL5 opening all the selected files as members of the ‘same external selection’ where they can easily be reviewed and edited etc…
The above must come with a disclaimer that not all variations of the scenarios have been full explored by me, and that the results were actually what I thought I saw etc. etc.
**However, what would be really nice is if those forum users with DAM systems and other photo managers could use those products to take a selection of photos and pass them to PL5 in a single operation with PL5 already running and also with PL5 shutdown. We can then compile a list of those that “play” in any way, those that “play” nicely and those that do not “play” at all (e.g, nothing happens or PL5 starts reading the entire directory).
In addition it would be useful to know which programs work well with other editing products and how well or otherwise they also work with PL5. If there are many that do well with other editors but run into problems with PL5 then there is a real case to press for PL5 to be improved**
The tests do not need to be done on particularly large directories of files just as long as it is easy to determine whether the files passed have been opened versus the entire directory. The tests are pertinent to both Mac and Windows systems albeit it might work out that no MAC system has a problem or …
The next part of the equation is how useful are the programs available for executing metadata searches in order to come up with clusters of photos to be passed to PL5 for editing etc. BUT if there is no way to get the photos across to PL5 in the way that the user wants then are they really that useful or should another program be used or should we be campaigning for changes to PL5.