Subj : Concurrent logins and data concurrency (last read msg pointers)
To   : Matthew Asham
From : Digital Man
Date : Mon Sep 05 2022 11:55 am

  Re: Concurrent logins and data concurrency (last read msg pointers)
  By: Matthew Asham to All on Mon Sep 05 2022 10:53 am

 > Greetings!
 >
 > New Synchronet operator here - used to run some boards back in the 90s and
 > am really happy to see Synchronet's longevity and open source model.
 >
 > While testing my board (Synchronet 3.19c on Debian 11 / git
 > 2458bfc3e336939c4893a36007ad34bb11c646b2) I've noticed that if I am logged
 > in via multiple nodes, my last message pointers don't seem to take affect on
 > any other node that I'm logged in to

That's correct. Message pointers are stored in memory until the user logs off.

 > or if reading messages through other
 > protocols such as NNTP.

Reading messages via NNTP does not use or change user's message pointers.

 > eg:
 >
 > user #1234 - login to node 1
 > user #1234 - login to node 2
 >
 > user #1234 - read all messages on node 1 - no new messages are present
 > user #1234 - session on node 2 continues to see the messages as unread

This is expected. That's why by default, concurrent user logins are not allowed.

 > This leads me to wonder whether it is safe to allow concurrent logins if
 > data for a session on node1 updates but the user has logged into another
 > node performing work and if things like login time or other data might be
 > overwritten when logging out.

Correct, the "last" type user data fields are overwritten upon logout (the last concurrent user to logout 'wins' the data race).

 > What can I expect in terms of data consistency when a user is logged in via
 > multiple services (NNTP/IMAP) or nodes?

NNTP is safe. IMAP, I'm not sure of, but you have the source in exec/imapservice.js (I didn't write that one). I suspect at least for email use, concurrent users with IMAP are "safe".
-- 
                                            digital man (rob)

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