> in retrospect you may have meant to say exactly that

Yes, but in retrospect I can see that maybe I should have more clearly separated the two questions. Thank you for the video. I watched it. I didn't know that SQLite looked so often at Postgres. But other parts of it were vaguely familiar. Maybe I saw it a long time ago and forgot about it.

  > there are some mostly-ready-only situations where a file-lock
  > isn't a problem (perhaps a small CMS, blog or similar)

I haven't used SQLite much, but it promises greater size and speed than most people would guess. As you can see from its website and the video you shared, D. Richard Hipp keeps tabs on where it's being used. "Developers report that SQLite is often faster than a client/server SQL database engine [when used as the database back-end on an application server]" (https://www.sqlite.org/whentouse.html) --- which is exactly what most people use a database for.

  > The sibling post of this comment gives a real-world SQLite example

--- of an application that I wouldn't use SQLite for. His mention of the writer blocking readers suggests that he wasn't using it in WAL mode. I had thought that the rollback journal and WAL were two names for the same thing. But SQLite didn't come out with the WAL until 2010. As it explains on its website, the rollback journal and WAL are alike, just backwards versions of each other. In rollback-journal mode (still the default) SQLite writes changes directly to its original database file but first backs up a snapshot of the data to the journal. With WAL mode turned on, the database first writes to the WAL, which eventually writes back to the original database (https://www.sqlite.org/wal.html).