In what way would I get you wrong Andreas? I made two extra databases since I posted the screenshot just to see. I could add a dozen without any problem.
Before I finish on this thread since I clearly have nothing to add or to assist some of you I will make a couple of remarks: don’t get me wrong though… Maybe the thread should be moved and retitled. “3PV for users with HUGE datasets” or something like that? Since my own view, which I am not pushing it on this forum, is that much, though not all of course and I don’t make it an initial assumption in any given case, regarding this ‘problem’ is really at the User strategy level. I think it is time for me to quit.
I don’t have any problems on DEVONthink 3, partly because I have chosen a good strategy for my use of DEVONthink 3: that is how I see it I am afraid. I don’t have a huge folder structure or multiple databases as a consequence, partly, of wise strategic decisions I have made regarding IT in general and DEVONthink 3 in particular. In fact decision I made years ago when I decided that though Filing Cabinet Skeumorphism was inevitable and necessary at UI to some extent, it was not de rigeur and not irreplacable, indeed I spent some time reconsidering my folder layout on DEVONthink 2 for those reasons. Of course the use of latin letters is Skeumorphic if you go hard enough at this distinction 
but the issue does arise sometimes when talking about Markdown and so on and its counterintuitive initial impression to those trained on quill and parchment.
We sometimes make bad decisions regarding data storage, file name conventions and so on? I certainly have. I though do not expect my IT to follow and cope with those poor decisions indefinitely. That included putting some files on Word docs that I can no longer open by the way, however easy they are to find.
It would and will be interesting to me to have to deal with a different kind of data set than the ones I currently use? I hope I get the opportunity and if and when I do I will report back as to any problems I get onto this forum. I won’t be surprised if I get none, well none due to deficiencies in DEVONthink 3 anyway. It is partly of academic interest to me now since my own usage of DEVONthink 3 is fine and has no friction points.
I don’t think I have had any significant IT bottlenecks in my own work for a couple of years now. Including on, I admit, the old DEVONthink. I still think the new one is an improvement regarding shortcuts and so on and performance in some sense.
“Huge Database” is a movable feast on IT. I am going to say, though it is not germane to this topic though it is, in my mind, starting to intrude. That much of the problem here is down to “user error” and poor strategic thinking. That is debatable and contentious of course and something I have enough grief dealing with in places other than this forum.
Since I also hold a contrarian view on much ‘date retention’ it is again best that I retreat before we fall into another contentious rabbit hole. I will make some remarks first though. I think we are running, as a society, into a situation where we have so much data ‘stored’ that we can’t sort through it in any useful way and its retention has negative but unintended effects in other ways.
This has a direct bearing on much of what I do by the way. I include in all this, endless and pointless and intrusive ‘video’ footage from Ring and other paranoia based companies, saved text messages and emails and photographic records of every trivial event. It is true though, that some of us, lawyers and so on in particular, don’t have a free hand in this. I know professionals now who save every text message. I now use Confide myself. Just as a kind of reminder to myself not to save stuff, not out of ‘security’ concerns.
In my own case, though to some of you my data base is ‘small’. It is probably ten times bigger than it really needs to be. I moved my personal photos out of DEVONthink 3 recently and reduced them to about 2% of what they were. I had what some consider a ‘small’ collection in the first place.
. I would say to Patrick though what I said before. There is a small learning curve on the upgrade. That is unavoidable and it was well over a week of heavy use before muscle memory returned on the ‘views’ for me.