Ledger Recovery flow parameters

The Ledger Recovery flow takes the following parameters:

val recoveryPeers: Collection<Party>,
val timeWindow: RecoveryTimeWindow? = null,
val useAllNetworkNodes: Boolean = false,
val dryRun: Boolean = false,
val useTimeWindowNarrowing: Boolean = true,
val verboseLogging: Boolean = false,
val recoveryBatchSize: Int = 1000,
val alsoFinalize: Boolean = false

recoveryPeers

recoveryPeers refers to a list of peer nodes to use for recovery. This parameter is mandatory unless using useAllNetworkNodes.

timeWindows

timeWindow refers to the recovery time window and defines a fromTime and untilTime. This parameter is mandatory, if not explicitly defined in configuration.

If a value is not specified by the user, the flow attempts to use the Corda Network or node configuration configured time window. The precedence order for this parameter is user-specified first, then node configuration, then Corda Network parameter.

useAllNetworkNodes

useAllNetworkNodes specifies if all peer nodes in the network map (excluding notary nodes) are to be used for recovery. This parameter is optional. The default value is false. If set to true, this parameter overrides the recoveryPeers list.

dryRun

dryRun can be used to identify missing transactions without performing actual recovery. This parameter is optional. It defaults to false.

useTimeWindowNarrowing

useTimeWindowNarrowing specifies whether to use a window narrowing algorithm to determine the optimal time window of transactions that are recoverable from a peer. It defaults to true. For example, if the original time window specifies 30 days and there are only three consecutive days of missing transactions from day 10 to day 12, a narrowed time window will determine that reconciliation only needs to take place for that three-day time period.

verboseLogging

verboseLogging specifies whether to log details of each recovered transaction. By default, the flow only reports total counts of recovered records.

recoveryBatchSize

recoveryBatchSize is a performance-tuning parameter that specifies how many records should be recovered in each interaction with a recovery peer. It has been fine-tuned to a value of 1,000 and can be tweaked to take into account the amount of physical memory available on a node host.

alsoFinalize

alsoFinalize specifies whether to attempt recovery of any IN_FLIGHT transactions recovered from a peer. It defaults to false. See also Finality Flow Recovery.

LedgerRecoverFlow

LedgerRecoverFlow returns a LedgerRecoveryResult which includes the following information:

• totalRecoveredRecords: Long; total number of recovered transaction distribution records. For the purpose of recovery counting, there is a one-to-one association with a single transaction on a node.
• totalRecoveredTransactions: Long; total number of recovered transactions. This may be less than the total number of distribution records if there are any transactions that already exist in the recovering node’s database.
• totalRecoveredInFlightTransactions: Long; total number of in-flight transactions recovered where the alsoFinalize option has been specified.
• totalErrors: Long; total number of errors encountered upon attempting recovery. See the node logs for details of these errors.

A LedgerRecoveryException is thrown if a fatal error occurs upon attempting recovery; for example, if no time window is specified and no time window configuration is defined.