[11.3] Bug/crash with powerlines in network mode

[ӔO]

There is an issue with powerlines in network mode.

If active powerlines or transformers are either built or destroyed, it can crash the server.
Whether or not the server crashes seems to be luck, but more often than not, the server will crash.
This does not crash the client, nor is this reproducible with a single player game.

I have also noticed that when powerline usage is checked through the minimap, despite there being more demand than generation, shows as very low usage.


I have tried to reproduce this with a local network game (127.0.0.1), but I cannot stay connected for more than a few seconds, even if the save game was edited to remove all power generation with there only being demand.

[jamespetts]

Thank you for that - were you not able to reproduce the client crash that you got with this?

[ӔO]

The client did not crash, but it also did not accept any new commands, nor did it disconnect from the server.

I would guess the server side froze

[jamespetts]

Looking into this now. As to the minimap issue: is the error with the map per se, or does the map accurately reflect reported usage, suggesting that the usage is too low (and therefore a substantive error with electricity distribution code)?

[ӔO]

usage on the powerlines themselves indicates 100% usage, but on the minimap, it shows as minimum.

This shows up on a local saved game.

There are three powerline networks in service.
Central Island shows maximum. 10000MW demand, 1200MW generation
Eastern Island shows maximum. 3000MW demand, 440MW generation
Continent shows minimum. 59500MW demand, 4500MW generation

[jamespetts]

So this is a minimap error, you think?

[ӔO]

After some investigation, I think there might be a bug with having more than 50,000MW demand.

Breaking up the powerline network in segments, to bring it below 49,000MW, will rectify the minimap indicator.
It is slightly difficult to get 50,000MW exactly...

[jamespetts]

Thank you for that.

My initial test running with Dr. Memory and deleting two active substations and some power lines has no effect. Investigating furhter...

[jamespetts]

Hmm - cannot reproduce this: running with a debugger on the server, no crashes or freezes could be identified on either client or server adding or deleting electrical infrastructure in the Crohead area. In what precise circumstances did these errors occur for you?

[ӔO]

I was using the remove powerline tool to remove the line from 1920,1265 to 1879,1256 when the server last crashed and did not come back up.

In the other crash, I connected Nutish to the powerline network via underground transformer.

[ӔO]

okay, I think I have reproduced this locally.
https://dl.dropboxusercontent.com/u/17111233/powerlinecrash.sve

Let the game run for a while in fast forward, keep it in FWD, maybe 3 to 4 months, then delete the sub station at 1229,1292 as my company.

For me, I got the game to crash after the colliery closed and I deleted the sub station. And a second time when I ran the game until January, at the very least, and deleted the sub station, even with the colliery still remaining open.


I think one of the key parts of this crash is that the game has to run for a while before deleting the sub station causes a crash. Immediately deleting the substation upon loading does not cause a crash.

[jamespetts]

Thank you for that: that is most helpful. After much testing, this is found and fixed on the 11.x branch.