An unstable situation. A curious case of lag.

  • Please make sure you are posting in the correct place. Server ads go here and modpack bugs go here
  • The FTB Forum is now read-only, and is here as an archive. To participate in our community discussions, please join our Discord! https://ftb.team/discord

GreenZombie

New Member
Jul 29, 2019
2,402
-1
0
While investigating a somewhat laggy direwolf20 server it became apparent that one of the causes of the very high frame time were 16,000 aspect orbs, discovered in an Opis report.

Opis was not kind enough to provide a Teleport To function on the Tracking / Entities report but a Kill-All removed them, and the servers frame time returned to more manageable levels.

Soon enough however, the Aspect Orbs were back at 5,000 and climbing, with a corresponding decrease in frame times and general block lag.

This time I found a chunk with an exceptionally high mean time, and Opis (For once) was not acting bloody stupid and actually teleported me there.

Aspect Orbs, all over the floor, of an empty cave. WTF? With a player present they quickly faded away, leaving me with a conundrum - there was no chunk loader. No mob farm. No player created structures in the area at all. Where had all the aspect orbs come from?

I investigated the cave for a bit and noticed a faint glow - equipping a thaumcraft hemlet - I see a node - a node with extremely low aspect counts. An Unstable Node that had been decaying in the cave, emitting aspect orbs as it decayed.

The Nodes undue influence on the server was almost done anyway - The highest aspect total it had on its 4 remaining aspects was 2, and two of the remaining aspects were at zero. Nonetheless, I smashed it so there would not have to be a cleanup later.

One problem solved.
Many problems remain - including a question - why on earth was the chunk with the node even loaded? The server has 10-20 clusters of chunks out in the wilderness that remain loaded - even over server restarts - that are not associated with any chunkloading tickets that /chunkloaders - or Opis - can show. They are not near spawn. They are not associated with any visible player structures at all: Watching the chunks in the Opis Mapwriter map shows that they seem to play the game of life - where the clusters change shape over time - sometimes as little as a single chunk is loaded - then back to 4 or 5. Wish I could figure this out.
 
Was this node, by chance, within two chunks of the edge of a chunkloaded area (either chunkloader-loaded, spawn-loaded, or player-loaded)? In chunks that are loaded, but are within a 5x5 chunk area of an unloaded chunk, entities are not processed, but blocks are. So, an unstable node would drop aspect orbs, but the orbs wouldn't despawn.

Is there a player's base between 120 and 160 blocks of the location of the node? If so, that could be the cause.
 
The area in question was in a chunk that was more than 10 chunks from spawn, a player, or a chunkloader ticket. It was in a small patch of loaded chunks, about 5 or so, so was definately less than five chunks away from unloaded chunks :P
 
Occurrence #2 - a player wanders past an activated Forgotten Sentinel.
The server starts to lag - all the players leave.
I investigate with Opis. The chunks list contains an entry for a chunk in dimension -7, with 13k tile entities. I center the map on it using the Mean Time overlay and Opis fills in the tile entity list with 'aspect orb'. I visit dimension -7 (FZHammer) at co-ordinates 500,64,90500 - I find pieces of a Sentinel - and another unstable node.

!@##$