There are several background tasks that Dgraph runs on the fly. It is “random” cuz some other tasks are prioritized more than others. So, a current task is paused in order to other with high priority to run.
Depending on the intensity of the Load, the configuration of your set up. How many resources you have available, how many Alphas are available. How many shards, the location of the tablets. Depending on many factors. This can cause resource drain. If you have a single Alpha where the vast majority of tablets are located and you are loading pointing only to that Alpha. It will choke.
Try to balance the load.
You can also remove compression with the flag --badger compression=none;
Change these values too --raft snapshot-after-entries=10000; snapshot-after-duration=30m; pending-proposals=256;
But don’t let your cluster with those configs changes for a long period. Dgraph needs log compaction, snapshots and so on.