ripple::TxQ::FeeMetrics Class Reference

Track and use the fee escalation metrics of the current open ledger. More...

Collaboration diagram for ripple::TxQ::FeeMetrics:

Classes
struct	Snapshot
	Snapshot of the externally relevant FeeMetrics fields at any given time. More...

Public Member Functions
	FeeMetrics (Setup const &setup, beast::Journal j)
	Constructor. More...
std::size_t	update (Application &app, ReadView const &view, bool timeLeap, TxQ::Setup const &setup)
	Updates fee metrics based on the transactions in the ReadView for use in fee escalation calculations. More...
Snapshot	getSnapshot () const
	Get the current Snapshot. More...

Static Public Member Functions
static FeeLevel64	scaleFeeLevel (Snapshot const &snapshot, OpenView const &view)
	Use the number of transactions in the current open ledger to compute the fee level a transaction must pay to bypass the queue. More...
static std::pair< bool, FeeLevel64 >	escalatedSeriesFeeLevel (Snapshot const &snapshot, OpenView const &view, std::size_t extraCount, std::size_t seriesSize)
	Computes the total fee level for all transactions in a series. More...

Private Attributes
const std::size_t	minimumTxnCount_
	Minimum value of txnsExpected. More...
const std::size_t	targetTxnCount_
	Number of transactions per ledger that fee escalation "works towards". More...
const std::optional< std::size_t >	maximumTxnCount_
	Maximum value of txnsExpected. More...
std::size_t	txnsExpected_
	Number of transactions expected per ledger. More...
boost::circular_buffer< std::size_t >	recentTxnCounts_
	Recent history of transaction counts that exceed the targetTxnCount_. More...
FeeLevel64	escalationMultiplier_
	Based on the median fee of the LCL. More...
const beast::Journal	j_
	Journal. More...

Detailed Description

Track and use the fee escalation metrics of the current open ledger.

Does the work of scaling fees as the open ledger grows.

Definition at line 374 of file TxQ.h.

Constructor & Destructor Documentation

FeeMetrics()

ripple::TxQ::FeeMetrics::FeeMetrics	(	Setup const &	setup,
		beast::Journal	j
	)

Constructor.

Definition at line 399 of file TxQ.h.

Member Function Documentation

update()

std::size_t ripple::TxQ::FeeMetrics::update	(	Application &	app,
		ReadView const &	view,
		bool	timeLeap,
		TxQ::Setup const &	setup
	)

Updates fee metrics based on the transactions in the ReadView for use in fee escalation calculations.

Parameters

app	Rippled Application object.
view	View of the LCL that was just closed or received.
timeLeap	Indicates that rippled is under load so fees should grow faster.
setup	Customization params.

Definition at line 86 of file TxQ.cpp.

getSnapshot()

Snapshot ripple::TxQ::FeeMetrics::getSnapshot

(

)

const

Get the current Snapshot.

Definition at line 452 of file TxQ.h.

scaleFeeLevel()

FeeLevel64 ripple::TxQ::FeeMetrics::scaleFeeLevel ( Snapshot const &  snapshot, OpenView const &  view  )

static

Use the number of transactions in the current open ledger to compute the fee level a transaction must pay to bypass the queue.

Parameters

view	Current open ledger.

Returns

A fee level value.

Definition at line 170 of file TxQ.cpp.

escalatedSeriesFeeLevel()

std::pair< bool, FeeLevel64 > ripple::TxQ::FeeMetrics::escalatedSeriesFeeLevel ( Snapshot const &  snapshot, OpenView const &  view, std::size_t  extraCount, std::size_t  seriesSize  )

static

Computes the total fee level for all transactions in a series.

Assumes that there are already more than txnsExpected_ txns between the view and extraCount. If there aren't, the result will be sensible (e.g. there won't be any underflows or overflows), but the level will be higher than actually required.

Note

A "series" is a set of transactions for the same account. In the context of this function, the series is already in the queue, and the series starts with the account's current sequence number. This function is called by tryClearAccountQueueUpThruTx to figure out if a newly submitted transaction is paying enough to get all of the queued transactions plus itself out of the queue and into the open ledger while accounting for the escalating fee as each one is processed. The idea is that if a series of transactions are taking too long to get out of the queue, a user can "rescue" them without having to resubmit each one with an individually higher fee.

Parameters

view	Current open / working ledger. (May be a sandbox.)
extraCount	Number of additional transactions to count as in the ledger. (If view is a sandbox, should be the number of transactions in the parent ledger.)
seriesSize	Total number of transactions in the series to be processed.

Returns

A std::pair as returned from mulDiv indicating whether the calculation result overflows.

Definition at line 230 of file TxQ.cpp.

Member Data Documentation

minimumTxnCount_

const std::size_t ripple::TxQ::FeeMetrics::minimumTxnCount_

private

Minimum value of txnsExpected.

Definition at line 378 of file TxQ.h.

targetTxnCount_

const std::size_t ripple::TxQ::FeeMetrics::targetTxnCount_

private

Number of transactions per ledger that fee escalation "works towards".

Definition at line 381 of file TxQ.h.

maximumTxnCount_

const std::optional<std::size_t> ripple::TxQ::FeeMetrics::maximumTxnCount_

private

Maximum value of txnsExpected.

Definition at line 383 of file TxQ.h.

txnsExpected_

std::size_t ripple::TxQ::FeeMetrics::txnsExpected_

private

Number of transactions expected per ledger.

One more than this value will be accepted before escalation kicks in.

Definition at line 387 of file TxQ.h.

recentTxnCounts_

boost::circular_buffer<std::size_t> ripple::TxQ::FeeMetrics::recentTxnCounts_

private

Recent history of transaction counts that exceed the targetTxnCount_.

Definition at line 390 of file TxQ.h.

escalationMultiplier_

FeeLevel64 ripple::TxQ::FeeMetrics::escalationMultiplier_

private

Based on the median fee of the LCL.

Used when fee escalation kicks in.

Definition at line 393 of file TxQ.h.

j_

const beast::Journal ripple::TxQ::FeeMetrics::j_

private

Journal.

Definition at line 395 of file TxQ.h.