What, exactly is "Synchronize Service"?

[LordP666]

I've searched this forum and found a bunch of posts about slow, or excessive "Synchronize Service", but I still don't understand what exactly is being synchronized.

BTW, the program seems to do this Synchronize quite a bit on my PC - I am making allowances since I'm currently doing a global "Convert Metadata to XMP" on over 33K images.

Can anyone explain it a bit more in-depth?

Thanks.

[G8DHE]

It synchronises the database and the metadata held within the image files or .xmp files.
You can choose to only hold the data only in the database or in both places, its an option in the Preferences.
Its described in the Manuals the CATALOGING section.

[LordP666]

Thanks G8DHE.

I thought that might be it, but the "Service" confused me a bit.

Is there an advantage to holding metadata within the image vs xmp files? I can see that having the database itself is useful as a backup, so I guess I'll keep that default.

[G8DHE]

Not all Image files can hold metadata so some will need to use .xmp anyway automatically, its swings and roundabouts if you decide to save as .xmp in all cases I'm not sure that it will not hold it in the image file if allowed anyway! Biggest problem is forgetting to move .xmps with the images themselves. I let PSU decide, but note that not all metadata will be held in the images some is only available in the database where it applies only to the database itself.
The whole area of metadata in images is so messy with competing and proprietary standards that there is no one solution, let alone the "problem" of social media platforms stripping all metadata and file names out these days!

[snowman1]

The database, aka the PSU catalog, is the heart of PSU and is what underlies your catalog structure, searches etc etc. Whilst you _could_ not read in any metadata from the image files (by altering PSU's default settings) it makes no sense that I can think of to do so.
Simply put, the main question is whether you bother writing data that you add in PSU, explicitly or implicitly - catalog structure, labels, etc - out to the files. Doing so takes more time but does mean all the data is also in the file, useful if you wish to transfer the file to someone else, upload it to a website outside of PSU, etc etc, or if you ever need to reconstruct the catalog from the files (better IMO to keep good catalog backups, but belt and braces and all that!).
And a secondary question is whether you write the data to the image file itself (and not all image file formats can contain metadata) or to sidecar files.

[LordP666]

Interesting.

Since I have Geotagged all the photos, and identified landmarks as well as some people I guess I'll leave well enough alone and keep updating the xmp + file, when applicable.

Thanks for all the help.