Red Hat Capsule 6 synchronization fails with deadlock detected errors.

Issue

• Capsule Synchronization fails with DeadLock detected on table core_artifact or core_contentartifact.

  Task errors: deadlock detected
  DETAIL:  Process 00001 waits for ShareLock on transaction 1000001; blocked by process 00001.
  Process 00001 waits for ShareLock on transaction 1000001; blocked by process 00002.
  HINT:  See server log for query details.
  CONTEXT:  while rechecking updated tuple (0001,1) in relation "core_artifact"
  
  deadlock detected
  DETAIL:  Process 11111 waits for ShareLock on transaction 11111112; blocked by process 11112.
  Process 11112 waits for ShareLock on transaction 11111111; blocked by process 11111.
  HINT:  See server log for query details.
  CONTEXT:  while inserting index tuple (1,2) in relation "core_artifact_sha256_key"
  
  deadlock detected
  DETAIL:  Process 11114 waits for ShareLock on transaction 11111114; blocked by process 11113.
  Process 11113 waits for ShareLock on transaction 11111113; blocked by process 11114.
  HINT:  See server log for query details.
  CONTEXT:  while rechecking updated tuple (123,45) in relation "core_contentartifact"
  

• If the mentioned relation is rpm_package and/or you are on Satellite/Capsule 6.12.1+, then please read this Solution / this BZ and follow this solution for remedy steps (that apply to both types of deadlocks).

• If the mentioned relation is rpm_modulemd and/or you are on Satellite/Capsule 6.13, follow the resolution as mentioned in this article.