>> sqlite insert statements can be very fast. sqlite.org claims 50000
>> or...
>
> I tried it, and got it down to... 30s!

That's great! :-)

> - Or do you think SQLite patterns (using "%") would do for now?  As
>   Mathieu pointed out, it's an unfortunate inconsistency with the rest of
>   Guix.  But maybe regexp support can be added in a second stage.

The inconsistency is unfortunate. Personally, I am in favor of dropping
regexp support everywhere in Guix, and only having literal string
search. But that is backward incompatible, and may be controversial.

In this specific case of file search, we could use the sqlite like
patterns, but not expose them to the user. For example, if the search
query is "<query>", we search for the LIKE pattern "%<query>%". I think
this addresses how users normally search for files. I don't think
regexps add much value.

Full text search may not be relevant to file search. Full text search is
more suited for natural language search involving such things as
stemming algorithms.