It has become normal to see a significant number of outbox-related DB serialization errors in the inventory-api logs. For example:

2026/02/26 13:39:30 /workspace/internal/data/outboxeventsrepository.go:16 ERROR: could not serialize access due to read/write dependencies among transactions (SQLSTATE 40001) 

These errors seem to relate to the delete in the code:

func PublishOutboxEvent(tx *gorm.DB, event *model_legacy.OutboxEvent) error {
	if err := tx.Create(event).Error; err != nil {
		return err
	}
	if err := tx.Delete(event).Error; err != nil {
		return err
	}
	return nil
} 

It is understood that this error can occur from time to time due to the use of Postgres' Serializable isolation level; however, it seems to be happening a lot. After a recent inventory-api deployment, it was observed in the logs of 1 pod 223 times in 7 minutes.

This task is to investigate why this is happening and to do something about it.

Slack thread:

https://redhat-internal.slack.com/archives/C059NUD49PD/p1772113343941489?thread_ts=1772034632.534889&cid=C059NUD49PD