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Juvix imports 

module arch.node.engines.shard_messages;

import prelude open;
import arch.node.types.basics open;
import arch.node.types.identities open;

Shard Messages

These are the messages that the Shard engine can receive/respond to.

Message interface

type ShardMsg KVSKey KVSDatum :=
  | ShardMsgKVSReadRequest (KVSReadRequestMsg KVSKey)
  | ShardMsgKVSWrite (KVSWriteMsg KVSKey KVSDatum)
  | ShardMsgKVSAcquireLock (KVSAcquireLockMsg KVSKey)
  | ShardMsgKVSLockAcquired (KVSLockAcquiredMsg)
  | ShardMsgKVSRead (KVSReadMsg KVSKey KVSDatum)
  | ShardMsgUpdateSeenAll (UpdateSeenAllMsg);

Message sequence diagrams

Transaction lock and read flow

sequenceDiagram
    participant WorkerEngine
    participant Shard
    participant Executor
    participant Mempool
    participant Consensus

    WorkerEngine->>Shard: KVSAcquireLock
    Shard->>WorkerEngine: KVSLockAcquired
    Executor->>Shard: KVSReadRequest
    Mempool->>Shard: UpdateSeenAll
    Consensus->>Shard: AnchorChosen
    Shard->>Executor: KVSRead
    Executor->>Shard: KVSWrite
Sequence Diagram: Transaction Lock and Read Flow

Message types

KVSReadRequestMsg

Read request from an Executor Engine.

type KVSReadRequestMsg KVSKey :=
  mkKVSReadRequestMsg@{
    timestamp : TxFingerprint;
    key : KVSKey;
    actual : Bool;
  };
Arguments
timestamp
The logical timestamp identifying the transaction at which to read
key
The key to read
actual
True if value is actually needed, false if just cleaning up a lazy read

KVSWriteMsg

Write request from an Executor Engine.

type KVSWriteMsg KVSKey KVSDatum :=
  mkKVSWriteMsg@{
    timestamp : TxFingerprint;
    key : KVSKey;
    datum : Option KVSDatum;
  };
Arguments
timestamp
The logical timestamp identifying the transaction in which to write
key
The key to write to
datum
The data to write, or none to indicate no write

UpdateSeenAllMsg

Update about seen transactions from a Mempool Worker Engine.

type UpdateSeenAllMsg :=
  mkUpdateSeenAllMsg@{
    timestamp : TxFingerprint;
    write : Bool;
  };
Arguments
timestamp
The logical timestamp at which to push the SeenAll value.
write
Whether it is the SeenAllReads or SeenAllWrites to update.

KVSAcquireLockMsg

Request to acquire locks for transaction execution.

type KVSAcquireLockMsg KVSKey :=
  mkKVSAcquireLockMsg@{
    lazy_read_keys : Set KVSKey;
    eager_read_keys : Set KVSKey;
    will_write_keys : Set KVSKey;
    may_write_keys : Set KVSKey;
    worker : EngineID;
    executor : EngineID;
    timestamp : TxFingerprint;
  };
Arguments
lazy_read_keys
Keys this transaction may read (only send values read in response to KVSReadRequests)
eager_read_keys
Keys this transaction will read (send values read as soon as possible)
will_write_keys
Keys this transaction will write
may_write_keys
Keys this transaction may write
worker
The Worker Engine in charge of the transaction
executor
The Executor for this transaction
timestamp
Specifies the transaction affiliated with these locks

KVSLockAcquiredMsg

Confirmation that locks were acquired.

type KVSLockAcquiredMsg :=
  mkKVSLockAcquiredMsg@{
    timestamp : TxFingerprint;
  };
Arguments
timestamp
The timestamp of the transaction which was locked.

KVSReadMsg

Value read response to executor.

type KVSReadMsg KVSKey KVSDatum :=
  mkKVSReadMsg@{
    timestamp : TxFingerprint;
    key : KVSKey;
    data : KVSDatum;
  };
Arguments
timestamp
The timestamp of the transaction which was read.
key
The key which was read.
data
The the data read.

ShardMsg

type ShardMsg KVSKey KVSDatum :=
  | ShardMsgKVSReadRequest (KVSReadRequestMsg KVSKey)
  | ShardMsgKVSWrite (KVSWriteMsg KVSKey KVSDatum)
  | ShardMsgKVSAcquireLock (KVSAcquireLockMsg KVSKey)
  | ShardMsgKVSLockAcquired (KVSLockAcquiredMsg)
  | ShardMsgKVSRead (KVSReadMsg KVSKey KVSDatum)
  | ShardMsgUpdateSeenAll (UpdateSeenAllMsg);

Engine components