Try to improve index usage for Job collection
Removing some indexes already covered for other existing ones to speed query plan decision


Index, | Proposal | Index Alternative  
-- | -- | --
"dataset", | DELETE: No query using only dataset |  
("dataset", "revision", "status"), | DELETE | ("type", "dataset", "revision", "config", "split", "status", "priority"),
("type", "dataset", "status"), | KEEP |  
("type", "dataset", "revision", "config", "split", "status", "priority"), | KEEP |  
("priority", "status", "created_at", "type", "namespace"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"), | KEEP |  
("priority", "status", "namespace", "type", "created_at"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
("priority", "status", "created_at", "namespace", "-difficulty"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
("status", "type"), | KEEP |  
("status", "namespace", "priority", "type", "created_at"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
("status", "namespace", "unicity_id", "priority", "type", "created_at"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
"-created_at", | DELETE: No query using only created_at |  
"finished_at" | KEEP |  
("unicity", "status", "created_at"), | KEEP |  


Try to improve index usage for Job collection: Removing some indexes already covered for other existing ones to speed query plan decision


Index, | Proposal | Index Alternative  
-- | -- | --
"dataset", | DELETE: No query using only dataset |  
("dataset", "revision", "status"), | DELETE | ("type", "dataset", "revision", "config", "split", "status", "priority"),
("type", "dataset", "status"), | KEEP |  
("type", "dataset", "revision", "config", "split", "status", "priority"), | KEEP |  
("priority", "status", "created_at", "type", "namespace"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"), | KEEP |  
("priority", "status", "namespace", "type", "created_at"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
("priority", "status", "created_at", "namespace", "-difficulty"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
("status", "type"), | KEEP |  
("status", "namespace", "priority", "type", "created_at"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
("status", "namespace", "unicity_id", "priority", "type", "created_at"), | DELETE | ("priority", "status", "created_at", "difficulty", "namespace", "type", "unicity_id"),
"-created_at", | DELETE: No query using only created_at |  
"finished_at" | KEEP |  
("unicity", "status", "created_at"), | KEEP |  

