Expand description
Transaction Payment Pallet
This pallet provides the basic logic needed to pay the absolute minimum amount needed for a transaction to be included. This includes:
- base fee: This is the minimum amount a user pays for a transaction. It is declared
as a base weight in the runtime and converted to a fee using
WeightToFee. - weight fee: A fee proportional to amount of weight a transaction consumes.
- length fee: A fee proportional to the encoded length of the transaction.
- tip: An optional tip. Tip increases the priority of the transaction, giving it a higher chance to be included by the transaction queue.
The base fee and adjusted weight and length fees constitute the inclusion fee, which is the minimum fee for a transaction to be included in a block.
The formula of final fee:
inclusion_fee = base_fee + length_fee + [targeted_fee_adjustment * weight_fee];
final_fee = inclusion_fee + tip;targeted_fee_adjustment: This is a multiplier that can tune the final fee based on the congestion of the network.
Additionally, this pallet allows one to configure:
- The mapping between one unit of weight to one unit of fee via
Config::WeightToFee. - A means of updating the fee for the next block, via defining a multiplier, based on the
final state of the chain at the end of the previous block. This can be configured via
Config::FeeMultiplierUpdate - How the fees are paid via
Config::OnChargeTransaction.
Re-exports
pub use pallet::*;Modules
Structs
Require the transactor pay for themselves and maybe include a tip to gain additional priority in the queue.
Implements the transaction payment for a pallet implementing the Currency
trait (eg. the pallet_balances) using an unbalance handler (implementing
OnUnbalanced).
The FeeDetails is composed of:
The base fee and adjusted weight and length fees constitute the inclusion fee.
Information related to a dispatchable’s class, weight, and fee that can be queried from the runtime.
A struct to update the weight multiplier per block. It implements Convert<Multiplier, Multiplier>, meaning that it can convert the previous multiplier to the next one. This should
be called on on_finalize of a block, prior to potentially cleaning the weight data from the
system pallet.
Traits
Something that can convert the current multiplier to the next one.
Handle withdrawing, refunding and depositing of transaction fees.
Type Definitions
Fee multiplier.