Struct pallet_transaction_payment::TargetedFeeAdjustment[−][src]

pub struct TargetedFeeAdjustment<T, S, V, M>(_);
Expand description

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.

given: s = previous block weight s’= ideal block weight m = maximum block weight diff = (s - s’)/m v = 0.00001 t1 = (v * diff) t2 = (v * diff)^2 / 2 then: next_multiplier = prev_multiplier * (1 + t1 + t2)

Where (s', v) must be given as the Get implementation of the T generic type. Moreover, M must provide the minimum allowed value for the multiplier. Note that a runtime should ensure with tests that the combination of this M and V is not such that the multiplier can drop to zero and never recover.

note that s' is interpreted as a portion in the normal transaction capacity of the block. For example, given s' == 0.25 and AvailableBlockRatio = 0.75, then the target fullness is 0.25 of the normal capacity and 0.1875 of the entire block.

This implementation implies the bound:

  • v ≤ p / k * (s − s')
  • or, solving for p: p >= v * k * (s - s')

where p is the amount of change over k blocks.

Hence:

  • in a fully congested chain: p >= v * k * (1 - s').
  • in an empty chain: p >= v * k * (-s').

For example, when all blocks are full and there are 28800 blocks per day (default in substrate-node) and v == 0.00001, s’ == 0.1875, we’d have:

p >= 0.00001 * 28800 * 0.8125 p >= 0.234

Meaning that fees can change by around ~23% per day, given extreme congestion.

More info can be found at: https://research.web3.foundation/en/latest/polkadot/overview/2-token-economics.html

Trait Implementations

Make conversion.

Minimum multiplier

Target block saturation level

Variability factor

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Convert from a value of T into an equivalent instance of Option<Self>. Read more

Consume self to return Some equivalent value of Option<T>. Read more

Converts self into T using Into<T>. Read more

Converts self into a target type. Read more

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait. Read more

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait. Read more

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s. Read more

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s. Read more

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait. Read more

Causes self to use its Binary implementation when Debug-formatted.

Causes self to use its Display implementation when Debug-formatted. Read more

Causes self to use its LowerExp implementation when Debug-formatted. Read more

Causes self to use its LowerHex implementation when Debug-formatted. Read more

Causes self to use its Octal implementation when Debug-formatted.

Causes self to use its Pointer implementation when Debug-formatted. Read more

Causes self to use its UpperExp implementation when Debug-formatted. Read more

Causes self to use its UpperHex implementation when Debug-formatted. Read more

Performs the conversion.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Performs the conversion.

Cast reference.

Cast reference.

Cast mutable reference.

Cast mutable reference.

Get a reference to the inner from the outer.

Get a mutable reference to the inner from the outer.

Pipes by value. This is generally the method you want to use. Read more

Borrows self and passes that borrow into the pipe function. Read more

Mutably borrows self and passes that borrow into the pipe function. Read more

Borrows self, then passes self.borrow() into the pipe function. Read more

Mutably borrows self, then passes self.borrow_mut() into the pipe function. Read more

Borrows self, then passes self.as_ref() into the pipe function.

Mutably borrows self, then passes self.as_mut() into the pipe function. Read more

Borrows self, then passes self.deref() into the pipe function.

Mutably borrows self, then passes self.deref_mut() into the pipe function. Read more

Pipes a value into a function that cannot ordinarily be called in suffix position. Read more

Pipes a trait borrow into a function that cannot normally be called in suffix position. Read more

Pipes a trait mutable borrow into a function that cannot normally be called in suffix position. Read more

Pipes a trait borrow into a function that cannot normally be called in suffix position. Read more

Pipes a trait mutable borrow into a function that cannot normally be called in suffix position. Read more

Pipes a dereference into a function that cannot normally be called in suffix position. Read more

Pipes a mutable dereference into a function that cannot normally be called in suffix position. Read more

Pipes a reference into a function that cannot ordinarily be called in suffix position. Read more

Pipes a mutable reference into a function that cannot ordinarily be called in suffix position. Read more

Should always be Self

Convert from a value of T into an equivalent instance of Self. Read more

Consume self to return an equivalent value of T. Read more

Immutable access to a value. Read more

Mutable access to a value. Read more

Immutable access to the Borrow<B> of a value. Read more

Mutable access to the BorrowMut<B> of a value. Read more

Immutable access to the AsRef<R> view of a value. Read more

Mutable access to the AsMut<R> view of a value. Read more

Immutable access to the Deref::Target of a value. Read more

Mutable access to the Deref::Target of a value. Read more

Calls .tap() only in debug builds, and is erased in release builds.

Calls .tap_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_borrow() only in debug builds, and is erased in release builds. Read more

Calls .tap_borrow_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_ref() only in debug builds, and is erased in release builds. Read more

Calls .tap_ref_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_deref() only in debug builds, and is erased in release builds. Read more

Calls .tap_deref_mut() only in debug builds, and is erased in release builds. Read more

Provides immutable access for inspection. Read more

Calls tap in debug builds, and does nothing in release builds.

Provides mutable access for modification. Read more

Calls tap_mut in debug builds, and does nothing in release builds.

Provides immutable access to the reference for inspection.

Calls tap_ref in debug builds, and does nothing in release builds.

Provides mutable access to the reference for modification.

Calls tap_ref_mut in debug builds, and does nothing in release builds.

Provides immutable access to the borrow for inspection. Read more

Calls tap_borrow in debug builds, and does nothing in release builds.

Provides mutable access to the borrow for modification.

Calls tap_borrow_mut in debug builds, and does nothing in release builds. Read more

Immutably dereferences self for inspection.

Calls tap_deref in debug builds, and does nothing in release builds.

Mutably dereferences self for modification.

Calls tap_deref_mut in debug builds, and does nothing in release builds. Read more

Attempts to convert self into T using TryInto<T>. Read more

Attempts to convert self into a target type. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

The counterpart to unchecked_from.

Consume self to return an equivalent value of T.

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more