My user-ID number showing as per your method is user_id=1.

User IDs as determined by the same method for all users increase chronologically and jump from 7 to 11 (included). So I have no idea what/who user_id_9 is, or was.

Would a deleted user keep its user_id in the Piwigo databse and possibly register an event if they attempt to log in? Which would imply that their username is still present there and associated with their previously attributed user_ID. But it does not make sense since the log shows "log out" events, which implies their log in attempts were successful, even though they would have been deleted.

There is no reason you would see user#9 if user#1 is connecting.

I have no idea what you mean by that.


I see user#9 activity when I select user#9 (6 Activities) from the drop-down list provided beside "Selected user". User#9 does not appear in the user list itself but appears in that drop-down list.

You should be able to find in the history of activities when a user was deleted.

Yes, both creation and deletion of user#9 are listed in my activity log as admin:

add 1 user added Friday 14 June 2024 14:04:32 * ******** **.***.**.*** pwg.users.add user#9
deletion 1 user deleted Sunday 4 May 2025 12:31:35 * ******** **.***.**.*** pwg.users.delete user#9

All 6 activities listed for ex-user#9 are dated between  Friday 14 June 2024 14:08:42 and  Thursday 25 July 2024, so during user#9 existence as valid user.

So your system apparently allows for activities from ex users to be displayed even after their deletion (which is good). To that effect, the list offered from the Acitivity /  Selected user drop down list includes deleted users... which is not entirely trivial a priori.