github.com/cockroachdb/cockroach@v20.2.0-alpha.1+incompatible/docs/tech-notes/txn_coord_sender/txncoordsender.puml (about)

     1  @startuml
     2  box "On any node using txns"
     3    participant "SQL executor\nor distsql server" as SQL
     4    participant "RootTxn\nor LeafTxn" as Txn
     5    participant TxnCoordSender
     6  end box
     7  participant cluster
     8  
     9  note over SQL: SQL transaction starts
    10  create Txn
    11  SQL -> Txn : client.NewTxn(Txn)
    12  create TxnCoordSender
    13  Txn -> TxnCoordSender : db.factory.TransactionalSender()
    14  TxnCoordSender -> TxnCoordSender : initialize txn object
    15  ...
    16  note over SQL: during query execution
    17  SQL -> Txn : txn.Run(client.Batch)
    18  Txn -> Txn : translate Batch into BatchRequest
    19  Txn -> TxnCoordSender: sender.Send(BatchRequest)
    20  TxnCoordSender -> TxnCoordSender: populate txn object into batch
    21  TxnCoordSender -> cluster : distsender.Send(BatchRequest)
    22  ...
    23  cluster --> TxnCoordSender : BatchResponse w/ txn object update
    24  TxnCoordSender -> TxnCoordSender: txn.Update(resp.Txn)
    25  TxnCoordSender --> Txn : BatchResponse
    26  Txn --> SQL : Batch modified in-place
    27  ...
    28  note over SQL
    29    when SQL txn completes
    30    (only on the SQL gateway / RootTxn)
    31  end note
    32  SQL -> Txn : Commit/Rollback/CleanupOnError
    33  Txn -> Txn : construct BatchRequest with EndTxnRequest
    34  Txn -> TxnCoordSender : sender.Send(BatchRequest)
    35  TxnCoordSender --> cluster : clean up (not always)
    36  TxnCoordSender -> TxnCoordSender : finalize txn
    37  @enduml