Why does a shallow-synced database take up exactly the same amount of space as the database on the Mac? For example, both my iPad and iPhone report the size of one particular shallow-synced database as 604.5 MB, which is identical to the size reported by Database Properties on the Mac.
I understand that the database index could be quite large on the iOS devices, but the database has a lot of images and so some difference should be expected. My other shallow-synced databases similarly report a size identical to that on the Mac. They do seem to be occupying that full amount of space, according to the size of Documents & Date as reported by Settings/Manage Storage in iOS for the DTTG2 app.
The database properties use the actual file size (but don’t include the size of metadata caches or indexes), no matter whether the files were downloaded or not. Therefore the properties are always the same & comparable.
So, does that mean that anyone using shallow sync to save space on their device is wasting their time? IOS seems to be reporting that a shallow-synced database is using the full amount of space.
I note that your feature comparison says shallow sync is “Space-saving metadata-only synchronization”
I am having difficulty understanding. The size displayed in a shallow-synced database iOS is the actual size of the database on the Mac. Yes? But it also seems to be the size of the shallow-synced iOS database too. Yes? So what do I make of the claim that the Pro Package offers “Space-saving metadata-only synchronization”?
Which means that a shallow sync of a database will require less storage space on the target device than if the database document files had all been downloaded by sync.
I understand what shallow sync is supposed to do, and that it is supposed to take up less storage space on the iOS device, and that the size reported in the app for a shallow-synced database is the size of the database on the Mac as if it had been fully synced. But from my original post: “They do seem to be occupying that full amount of space, according to the size of Documents & Date as reported by Settings/Manage Storage in iOS for the DTTG2 app.”
So to add some data: I have 9 databases, all shallow-synced to an iPad. The size of each one reported in the iOS app (from the info button) is identical to the size reported in Database Properties on the Mac. That I understand. When I add up these reported sizes I get a total of 1940 MB. As they have been shallow-synced, I expect the space taken up on the iPad to be less than that (and by a reasonable amount if shallow sync is to be worth bothering with). So I look in Settings/General/Manage Storage on the iPad and it tells me the DTTG2 Documents & Data are taking up 1860 MB. So a saving of 80 MB by shallow syncing from what would have been 1940 MB with a full sync. Yet I would expect a far larger saving than that. For example, a search on the Mac of all imported jpeg files in those 9 databases gives a total of 350 MB. As these shouldn’t figure in the storage for the shallow-synced databases then I would expect a saving of at least that. What don’t I understand?
Settings/General/Manage Storage is the required disk space whereas the database properties count only the files inside the database (e.g. metadata storage, search index, backups or temporary files aren’t counted).
Thanks for the clarifications. So in my example given. the Settings/General Manage Storage figure of 1860 MB is just metadata storage and search index (there are no backups or temporary files - I did a fresh install and sync for the data quoted). In other words the metadata and search index take up almost the same amount of storage (1940 MB in my example) as the files themselves if I had done a full sync.
The storage space saving of shallow sync compared to download all will vary with a database’s document file content.
For example, if all your document files are plain text, the saving will be much less than if all your document files were heavy in non-text content such as formatting and images - such as WebArchive or PDF+Text and even more drastically for image files such as JPEG or image-only PDFs - assuming that the same amount of text content, metadata about group organization, tags, etc. in the two databases.
I must agree that the apparently very large file size of even a wholly shallow-synced database defies the purpose of the whole setup. I gave up syncing my main database (40 GB, mostly pdfs, 82.000.000 words altogether) to my iphone when roughly 5% of the database already took up 2GB of space.