I just want to give a perspective of someone that uses the 'eternal history' in bash per Eli Bandersky [1] and reluctance to use something like atuin (without/ignoring shared history).

First, as for speed and responsiveness, if there is a degradation, it is imperceptible to me. I wouldn't have a clue that my interactive shell is slowing down because it is logging a command to ~/.persistent_history.

My persistent_history is 4MB and has been migrated from machine to machine as I've upgraded, it's never felt slow to edit with (neo)vim or search with system supplied grep.

Eli's way of doing it also includes the timestamps for all commands, so it's easy to trace back when I had run the command, and duplicates are suppressed. In fact my longest persistent_history goes back to 2019-07-04, so I've been using it for quite some time now.

But the larger point I wanted to make is that I wouldn't feel comfortable switching this, in my opinion, quite efficient setup to displace it with an sqlite database. That would require a special tool to drill through the history and search rendering simple unix utilities useless. As Eli suggested, if your history gets too big, simply rotate the file and carry on. I have the alias phgrep to grep ~/.persistent_history, but I can easily have another alias to grep ~/.persistent_history*.

[1]: https://eli.thegreenplace.net/2013/06/11/keeping-persistent-...

You don't have to setup shared history with Atuin if you don't want to and that's what's holding you back. Otherwise it hits the rest of your requirements. Just don't hesitate to change from the default config.