KVSRead

• from Shard

Purpose

Executors have to read data from keys to execute TransactionCandidates. When a Shard has determined what the value read is at the appropriate timestamp, it sends a KVSRead to the appropriate Executor.

Structure

Field	Type	Description
timestamp	TxFingerprint	the timestamp at which the datum was read
key	KVSKey	the key from which the datum is read
data	KVSDatum	the datum read

The timestamp should match the timestamp of the TransactionCandidate for this Executor.

Effects

These read values are input for the TransactionExecutable. Some may be lazy inputs, and some may never be used, but they're all inputs. If this lets us finish the TransactionExecutable, it may trigger KVSWrites (outputs of the executable), and shutting down the Executor entirely.

Triggers

• to Shard: KVSWrite for each value the TransactionExecutable outputs to write send a KVSWrite message to the appropriate Shard
• to Shard: KVSReadRequest for each lazy read the TransactionExecutable now requires, and each lazy read the TransactionExecutable hasn't read when it terminates: send a KVSReadRequest message to the appropriate Shard
• to Worker Engine: ExecutorFinished If TransactionExecutable has terminated then notify the curator specified in ExecuteTransaction

that the transaction is done with an ExecutorFinished. - to User,Solver: ExecutionSummary The issuer of the transaction request is always provided with the ExecutionSummary