Indexing on all my iOS devices?

I’m new to roon, and couldn’t find an answer to this in the manuals.
I’m using an iMac as my core, and it’s furiously indexing all my stuff…
however I want to access my music via a couple of iPads and iPhones - when I open roon up on these devices it seems to want to sync all my files in a database on the device!
I’m sure this is not right, perhaps just an effect of the fact that all my tracks have not been captured by the core on my iMac…
…I hope!
anyone able to answer this?
best regards,

No they don’t.
Why do you think they do?
What does “sync” mean?

thanks Anders,
here’s a screen shot of I’m iMac (the core system) below, followed by a screen shot on my iPad Pro (just a ‘player’ using the iMac ‘core’)
they both seem to be adding music to library - my iPhone is doing the same, made me think that each device needs to index!! seemed strange to me, and my thinking was that it was just because the system is still gathering all the files and indexing on the core database…
should I just ignore the iPad ‘adding music to library’ or will this corrupt things?
best regards,

iMac - core screen shot below

iPad Pro screen shot below

Funny, I have never seen that message.
Anyway, the iPad is just informing you what the Mac is doing. The iPad doesn’t do any such work itself. You can turn it off.

I am not sure, but I imagine you can start playing music while the Mac is adding music.

thanks @AndersVinberg

your right, I can play music while it is adding music to library (now almost 50%, it’s taking its time!)

it does seem a bit strange. when I set up my iPad as a control, it asked me if I wanted to back up the database. I’m taking it that this is redundant as it will just be a duplicate o the main database on the Core run on my iMac…

best regards,