Bugzilla

this is indeed just the effect of us limiting the database size when available disk size is small, nowadays Firefox profile can take multiple GiB of space, so 800MiB is not enough.
Bug 1753729 should improve the situation by using a larger limit, but we'll keep limiting the size when disk doesn't have enough space.
You can override the limit setting the hidden places.history.expiration.max_pages pref, though I really don't suggest doing it, as it may cause other problems and we would unlikely spend time fixing issues caused by hidden prefs.

this is indeed just the effect of us limiting the database size when available disk size is small, nowadays Firefox profile can take multiple GiB of space, so 800MiB is not enough.
Bug 1753729 should improve the situation by using a larger limit, but we'll keep limiting the size when disk doesn't have enough space.
You can override the limit setting the hidden `places.history.expiration.max_pages` pref, though I really don't suggest doing it, as it may cause other problems and we would unlikely spend time fixing issues caused by hidden prefs.