Stuck construction bots
Posted: Mon Nov 14, 2016 12:58 am
We have a very large and sprawling base (~1.3k roboports), all of which is covered by the same logistics network. This game started as multiplayer and has been continued as multiplayer for the most part, though with some playtime via single player.
Currently there are a large number of ghost entities placed via blueprints which the construction bots have not yet built. Now, that may not sound like a bug, but said ghost entities have been lingering for multiple hours now, still not built, while everything around them that was blueprinted at the same time was constructed multiple hours ago. All of the materials necessary for construction are available in network, there are lots of available construction bots (~5500/6000), and there is lots of storage space available in storage chests in network. Even if they were to run out of power mid flight, the bots should have been able to go from one end of the base to the other multiple times by now.
This all started happening around the time I expanded the base to the south, blueprinting the long southern wall. Due to the Roboport coverage, I fully expected that to take a long time to construct (and it did - though there are some "stuck" ghost entities in it too). I don't recall now the timing of the solar array blueprinting in relation to the southern wall, but they probably overlapped. I believe at one point the southern wall logistics network was disconnected from the rest of the network, as a biter attack took out some power poles and/or Roboports. However, currently the southern logistics network is connected to the rest of the network via multiple points.
I first noticed the problem when I saw that the solar array expansion still hadn't been completed. When I went to investigate, I noticed that there was a number of items still queued for deconstruction in the way of some of the blueprinted items. Clearing the buildings (belts, mostly) queued for deconstruction manually allowed a number of the blueprinted buildings to be placed immediately, as there was a construction bot waiting there. I left the bots to their work (again), thinking they would figure things out eventually, and added (many) more storage chests just in case. A couple hours later, I started placing blueprints in the newly secured southern area and noticed again that some of the blueprinted buildings were not getting constructed, even though everything around them had been constructed a long time ago, I manually constructed most of what was missing here, but there are still a few ghosts left in that area. At this point I again noticed that the bots had made zero progress on the solar array construction, and tried to force the issue by walking past the ghost buildings with a Personal Roboport and the requisite items, but to no effect. If I manually place the items ghosted for the blueprint, I can see that the number of available construction bots increases by one per ghost removed.
I've been letting the game run while writing this bug report while keeping an eye on the number of available construction bots. Over the course of half an hour or so, the number of available construction bots has never risen above 5520/6027. The number will waver slightly as they respond to biter attacks, but it never rises back above 5520/6027. This confirms a more casual observation I had earlier, that there seemed to be 500 or so "stuck" construction bots, as even when I wasn't constructing anything, there was still some 500 construction bots unavailable.
Unfortunately, I can't tell where the 500ish unavailable bots are exactly, but they seem to be assigned to the ghost items on the map, as the Personal Roboport bots don't respond to them, and clearing each ghost frees up a construction bot. I assumed this problem would clear if I waited long enough, but it's not improving over the course of multiple hours, and the problem of ghost buildings never getting constructed is also affecting newly placed blueprints.
Just now I scoured the entire south wall and noticed one area where construction bots were flying to a destination over a large area not covered by Roboports, realizing they would run out of power before they got there, turning around, running out of power, and then eventually getting back to the original Roboport to charge, only to repeat the cycle again. These construction bots seemed happen to repeat this cycle forever. I added some additional Roboports to cover the uncovered area and they were then able to make it to their destination, and several of the ghosted buildings got built. However, there are still several hundred construction bots unavailable and corresponding building ghosts, which may be repeating this same pattern somewhere else I haven't noticed yet.
Why would the construction bots repeatedly choose a path that they know they won't complete? It would be much much better if they either:
a) completed the path anyways, even though it'll take a long time because they'll run out of power part of the way there, or
b) chose a longer path (ie, not a straight line), but with more intermediate charging points available
Particularly smart bots would choose the faster of the above two options.
Alternatively, if we could at least see where construction bots are (via a map overlay or similar), or get some sort of warning when they're stuck in a loop like described, we could at least manually address this problem. As it is, it is very difficult to diagnose.
I have attached a save file near some of the oldest ghost entities in the solar array.
Currently there are a large number of ghost entities placed via blueprints which the construction bots have not yet built. Now, that may not sound like a bug, but said ghost entities have been lingering for multiple hours now, still not built, while everything around them that was blueprinted at the same time was constructed multiple hours ago. All of the materials necessary for construction are available in network, there are lots of available construction bots (~5500/6000), and there is lots of storage space available in storage chests in network. Even if they were to run out of power mid flight, the bots should have been able to go from one end of the base to the other multiple times by now.
This all started happening around the time I expanded the base to the south, blueprinting the long southern wall. Due to the Roboport coverage, I fully expected that to take a long time to construct (and it did - though there are some "stuck" ghost entities in it too). I don't recall now the timing of the solar array blueprinting in relation to the southern wall, but they probably overlapped. I believe at one point the southern wall logistics network was disconnected from the rest of the network, as a biter attack took out some power poles and/or Roboports. However, currently the southern logistics network is connected to the rest of the network via multiple points.
I first noticed the problem when I saw that the solar array expansion still hadn't been completed. When I went to investigate, I noticed that there was a number of items still queued for deconstruction in the way of some of the blueprinted items. Clearing the buildings (belts, mostly) queued for deconstruction manually allowed a number of the blueprinted buildings to be placed immediately, as there was a construction bot waiting there. I left the bots to their work (again), thinking they would figure things out eventually, and added (many) more storage chests just in case. A couple hours later, I started placing blueprints in the newly secured southern area and noticed again that some of the blueprinted buildings were not getting constructed, even though everything around them had been constructed a long time ago, I manually constructed most of what was missing here, but there are still a few ghosts left in that area. At this point I again noticed that the bots had made zero progress on the solar array construction, and tried to force the issue by walking past the ghost buildings with a Personal Roboport and the requisite items, but to no effect. If I manually place the items ghosted for the blueprint, I can see that the number of available construction bots increases by one per ghost removed.
I've been letting the game run while writing this bug report while keeping an eye on the number of available construction bots. Over the course of half an hour or so, the number of available construction bots has never risen above 5520/6027. The number will waver slightly as they respond to biter attacks, but it never rises back above 5520/6027. This confirms a more casual observation I had earlier, that there seemed to be 500 or so "stuck" construction bots, as even when I wasn't constructing anything, there was still some 500 construction bots unavailable.
Unfortunately, I can't tell where the 500ish unavailable bots are exactly, but they seem to be assigned to the ghost items on the map, as the Personal Roboport bots don't respond to them, and clearing each ghost frees up a construction bot. I assumed this problem would clear if I waited long enough, but it's not improving over the course of multiple hours, and the problem of ghost buildings never getting constructed is also affecting newly placed blueprints.
Just now I scoured the entire south wall and noticed one area where construction bots were flying to a destination over a large area not covered by Roboports, realizing they would run out of power before they got there, turning around, running out of power, and then eventually getting back to the original Roboport to charge, only to repeat the cycle again. These construction bots seemed happen to repeat this cycle forever. I added some additional Roboports to cover the uncovered area and they were then able to make it to their destination, and several of the ghosted buildings got built. However, there are still several hundred construction bots unavailable and corresponding building ghosts, which may be repeating this same pattern somewhere else I haven't noticed yet.
Why would the construction bots repeatedly choose a path that they know they won't complete? It would be much much better if they either:
a) completed the path anyways, even though it'll take a long time because they'll run out of power part of the way there, or
b) chose a longer path (ie, not a straight line), but with more intermediate charging points available
Particularly smart bots would choose the faster of the above two options.
Alternatively, if we could at least see where construction bots are (via a map overlay or similar), or get some sort of warning when they're stuck in a loop like described, we could at least manually address this problem. As it is, it is very difficult to diagnose.
I have attached a save file near some of the oldest ghost entities in the solar array.