Execution of Cassandra's logged batch

batches.puml

@startuml

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participant "Client" as client
database "Coordinator DSE node" as cnode
database "Batchlog DSE nodes" as bnode
database "DSE Nodes" as onode

alt successful case
        client -> cnode: send batch request
        activate cnode
                cnode -> bnode: 2 copies of batchlog\n(could be less in some edge cases)
                bnode --> cnode: confirmed
                alt successful batch execution
                        loop number of statements (done async)
                             cnode -> onode: execute statements
                             onode --> cnode: result
                        end
                cnode -> bnode: remove batchlog
                cnode --> client: confirm execution
                deactivate cnode
        else batch execution failed
                cnode --> client: batch write timeout
                loop until applied
                        activate bnode
                                bnode --> bnode: detects that batch still exist
                                loop number of statements (done async)
                                     bnode -> onode: execute statements
                                     onode --> bnode: result
                                end
                                bnode -> bnode: remove batchlog from other nodes
                        deactivate bnode
                end
        end
else batchlog write problem
        cnode --> client: batchlog write timeout
        client -> cnode: retry request
        note right of cnode: retry request on other coordinator
end

@enduml