@justinwyllie the second time I attempted to open a Lightroom database during DxPL 5 Beta testing it failed to open. They both use SQLite databases and in general use I have not found there to be problems with DxPL db but I destroy the database frequently so that I can more easily inspect the database entries.
There were problems for some users during the DxPL4 to DxPL5 transition where DxPL5 lost its way and created a new database but hopefully DxO have learned from that situation.
@Franky there is no data with respect to ‘Projects’ in the DOP but all other data pertaining to the image contained in the database is written to the DOP after being updated to the database within a maximum of 20 seconds.
The database is the primary data storage mechanism used by DxPL and the DOP is a copy which will be “adopted” if it discovers an image with DOP that is not already in the database.
Hence you can “throw” the database away regularly providing you do not want to use ‘Projects’.
Please be aware that the DOP will always contain the metadata that DxPL knows about and the xmp sidecar will contain the metadata that DxPL and the user chooses to write back out which makes this statement true and false at the same time!?
Arguably also right and wrong at the same time. DxPL will do nothing to actually recover a database it will start with an empty database and if you visit no directories with images and DOPs it will continue to be empty, i.e. it does not actively seek images and/or DOPs.
As the user traverses directories so all the pertinent data contained in the directory will automatically be imported into the database, using DOPs if they are present, using xmp sidecar files if they are present according to the “first discovery” rules.
There is no selectivity with respect to images in a directory, all will be imported when the directory is “discovered”/selected by the user for the “first time” with respect to the contents of the database, i.e. the database does not already have an entry for the directory in the database.
Only the directory selected will be “imported”, no adjoining directories nor any sub-directories will be automatically “discovered” and imported, unless and until the user chooses to “visit” those directories and sub-directories.
The DxPL db backup and restore options are available and adequate but not exemplary but there will be no prompt on closedown offering/reminding to backup the database, that is entirely a user decision.