Because you get to have fun with lots of spinning colourfull balls.
I thought it was how good it makes me look. 
Dollars to doughnuts, you are getting slowdowns because all free RAM has been exhausted, and the ongoing procedure requires moving data back and forth between RAM and Virtual Memory swap files on your drive. Especially on conventional hard drives, read/write speeds are orders of magnitude slower than in RAM.
When you next see a “beach ball”, launch Activity Monitor and you will probably see little or no available free RAM, and sizable VM swap files.
There are two approaches to keeping your database operations running at the full speed of your Mac.
- Hold database size down to a total word count (the most important size measurement - displayed in Database Properties) that will fit comfortably within your available free RAM.
Until recently, DEVONthink ran as a 32-bit application, with a maximum addressable memory space of 4 GB. The upper limit on databases was that the loaded database and the current procedures couldn’t address more than 4 GB memory, else memory errors would start. Having 8 or 16 or 32 GB installed RAM didn’t help.
And until recently I was doing most of my database work on a laptop that held a total of 4 GB installed RAM. But the operating system needs RAM, as do any other open applications, so my databases had less than 4 GB physical RAM available. And Apple’s memory management, while good, doesn’t prevent “crud” (unused data that’s not being removed) from building up in RAM, so it’s common to see free RAM decrease over time.
My rule of thumb was that I could avoid spinning balls (at least for a considerable time) by holding the maximum word count total of open databases at or below 40 million words. I monitored available free RAM, keeping it to at least 750 MB free RAM, so that everything ran at full speed. My topical databases designed in this way worked well for me, for years. But I had to manage free RAM and take action to restore it when necessary, to keep a spinning ball from showing up.
- Now there’s a better way, with the current 64-bit DEVONthink and a current Mac loaded with more RAM. Running in 64-bit mode means DEVONthink can address a lot more memory space. And my current MacBook Pro (Retina) has 16 GB RAM. I can run larger databases or a larger (in total word count) set of open databases that could use more than 4 GB addressable memory space, and without creating Virtual Memory swap files and slowing down (within reason, of course).
Right now I’ve got my “standard” set of 5 open databases running under DEVONthink Pro Office. I’ve got several other applications running. Wonder of wonders, there’s 9 GB free RAM. No pageouts, no VM swap file use, no beach balls.
DEVONthink is FAST! 
bill, mind telling us/me what machine you are using for DT?
As noted, a 2012 MacBook Pro (Retina) with 2.6 GHz Intel Core i7, 16 GB RAM, 500.28 GB SSD. It’s the fastest Mac I’ve ever owned, and yet is light enough to carry around. It absolutely blows away my iMac with an earlier version of the i7 CPU and a conventional hard drive.
But by managing database sizes and managing free RAM, I had for years avoided spinning balls on laptops with 4 GB RAM.
Thanks for all that information, Bill.
Unfortunately I’m on a machine that has a maximum memory allowed of 3 GB. Which I already have. I see the spinning beachball a lot as well. I’ve manages to split databases up a bit and that helps but not enough.
Can’t get a newer, more memory machine until a few key apps are avaialable under the latest operating system. Which given it’s been 5 years since an update may be never… :sigh:
Any tips when you are memory limited and cannot fix that?
Bill, so I’ve been keeping my activity monitor open and have noted that it’s not the case that DT is using an abundance of CPU. The use is fine (6% for example) but what does happen - and I don’t know what it means - is that the name of the software goes red in the activity monitor. Any idea what that is about? Thanks.
Have you checked the Console logs for any information, especially repeated entries?
I’m not sure what that means, but I’ll look into it. Thanks,
When the name goes red it means the app has stalled or become unresponsive. This may be a transient condition as some process is working and needs more resources or it may eventually hang.
In the Finder, press Command-Shift-G and paste: /Applications/Utilities/Console.app . Looking at All Messages you can see if there’s a repeated statement. You can even search for a particular app in the searchField at the top right.