Zugg Software :: View topic

Posted: Fri Jan 29, 2010 6:43 pm

Now then, I'm not sure how to get this happen again but i just had an odd catastrophic loss of data.

My system froze up, no blue screen, just stopped updating, so i give the system a soft boot.
Upon booting i try to open CMUD and return to my game.

CMUD throws a fit layout is all out of whack with no windows at all showing.
So i retstart CMUD and hold down shift to open the session. Still out of whack.
So i go into settings editor and try turning visability of my main window off and on.

Restart CMUD again holding shift... windows pop up at last, but are still semi docked even though i held down shift.

Finally i get things looking right visually, log in and my first tip of something is wrong, none of my highlights are working.
So i go into my settings to see what is wrong..

All triggers, aliases, variables and buttons are gone.
The class infrastructure is still there, as are windows, events, statuses, and defined mapper room scripts.

I have no idea what happened, but it seems i must start from scratch.

It did this not only to my session, but also for any shared packages as well, such as the colourwheel i got off the package library.

Posted: Fri Jan 29, 2010 7:58 pm

This is on my bug list, but I haven't found any way to reproduce it yet. It seems that CMUD will sometimes freeze in the background thread that is saving your settings to disk. If you open the *.pkg file in Notepad, you can usually see and recover most of your scripts via manual copy/paste, but for some reason SQLite has all of the database records marked as deleted.

Since CMUD never deletes all of your settings unless you use #killall, I am unsure how this can ever happen. The whole reason for writing CMUD from scratch to use databases was to avoid this kind of catastrophic data loss. CMUD is even using proper Transactions to protect the *.pkg file from ever being corrupted.

All I can think of is that the background database updater happens to run exactly at the time CMUD is closing and has removed the settings from memory, making the database think that the settings all need to be deleted from the disk. But it doesn't sound like this happened to you when closing CMUD.

Unfortunately, since nobody has found a way to reproduce this yet and it seems to be a pretty rare occurrence, it's a very hard problem for me to track down, even though it is also a really high priority (anything that corrupts or loses data like this is a very high priority with me).

Posted: Fri Jan 29, 2010 10:10 pm

I am more surprised by the fact that any settings survived at all to be honest.