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Constants

The following sections contain the module constants, also known as parameter types. These can only be changed as part of a runtime upgrade. On the api, these are exposed via api.consts.<module>.<method>.

(NOTE: These were generated from a static/snapshot view of a recent default asset-hub-polkadot runtime. Some items may not be available in older nodes, or in any customized implementations.)

assetConversion​

liquidityWithdrawalFee: Permill​

  • interface: api.consts.assetConversion.liquidityWithdrawalFee
  • summary: A fee to withdraw the liquidity.

lpFee: u32​

  • interface: api.consts.assetConversion.lpFee
  • summary: A % the liquidity providers will take of every swap. Represents 10ths of a percent.

maxSwapPathLength: u32​

  • interface: api.consts.assetConversion.maxSwapPathLength
  • summary: The max number of hops in a swap.

mintMinLiquidity: u128​

  • interface: api.consts.assetConversion.mintMinLiquidity
  • summary: The minimum LP token amount that could be minted. Ameliorates rounding errors.

palletId: FrameSupportPalletId​

  • interface: api.consts.assetConversion.palletId
  • summary: The pallet's id, used for deriving its sovereign account ID.

poolSetupFee: u128​

  • interface: api.consts.assetConversion.poolSetupFee
  • summary: A one-time fee to setup the pool.

poolSetupFeeAsset: StagingXcmV4Location​

  • interface: api.consts.assetConversion.poolSetupFeeAsset
  • summary: Asset class from [Config::Assets] used to pay the [Config::PoolSetupFee].

assets​

approvalDeposit: u128​

  • interface: api.consts.assets.approvalDeposit
  • summary: The amount of funds that must be reserved when creating a new approval.

assetAccountDeposit: u128​

  • interface: api.consts.assets.assetAccountDeposit
  • summary: The amount of funds that must be reserved for a non-provider asset account to be maintained.

assetDeposit: u128​

  • interface: api.consts.assets.assetDeposit
  • summary: The basic amount of funds that must be reserved for an asset.

metadataDepositBase: u128​

  • interface: api.consts.assets.metadataDepositBase
  • summary: The basic amount of funds that must be reserved when adding metadata to your asset.

metadataDepositPerByte: u128​

  • interface: api.consts.assets.metadataDepositPerByte
  • summary: The additional funds that must be reserved for the number of bytes you store in your metadata.

removeItemsLimit: u32​

  • interface: api.consts.assets.removeItemsLimit

  • summary: Max number of items to destroy per destroy_accounts and destroy_approvals call.

    Must be configured to result in a weight that makes each call fit in a block.

stringLimit: u32​

  • interface: api.consts.assets.stringLimit
  • summary: The maximum length of a name or symbol stored on-chain.

aura​

slotDuration: u64​

  • interface: api.consts.aura.slotDuration

  • summary: The slot duration Aura should run with, expressed in milliseconds. The effective value of this type should not change while the chain is running.

    For backwards compatibility either use [MinimumPeriodTimesTwo] or a const.

balances​

existentialDeposit: u128​

  • interface: api.consts.balances.existentialDeposit

  • summary: The minimum amount required to keep an account open. MUST BE GREATER THAN ZERO!

    If you really need it to be zero, you can enable the feature insecure_zero_ed for this pallet. However, you do so at your own risk: this will open up a major DoS vector. In case you have multiple sources of provider references, you may also get unexpected behaviour if you set this to zero.

    Bottom line: Do yourself a favour and make it at least one!

maxFreezes: u32​

  • interface: api.consts.balances.maxFreezes
  • summary: The maximum number of individual freeze locks that can exist on an account at any time.

maxLocks: u32​

  • interface: api.consts.balances.maxLocks

  • summary: The maximum number of locks that should exist on an account. Not strictly enforced, but used for weight estimation.

    Use of locks is deprecated in favour of freezes. See https://github.com/paritytech/substrate/pull/12951/

maxReserves: u32​

  • interface: api.consts.balances.maxReserves

  • summary: The maximum number of named reserves that can exist on an account.

    Use of reserves is deprecated in favour of holds. See https://github.com/paritytech/substrate/pull/12951/

foreignAssets​

approvalDeposit: u128​

  • interface: api.consts.foreignAssets.approvalDeposit
  • summary: The amount of funds that must be reserved when creating a new approval.

assetAccountDeposit: u128​

  • interface: api.consts.foreignAssets.assetAccountDeposit
  • summary: The amount of funds that must be reserved for a non-provider asset account to be maintained.

assetDeposit: u128​

  • interface: api.consts.foreignAssets.assetDeposit
  • summary: The basic amount of funds that must be reserved for an asset.

metadataDepositBase: u128​

  • interface: api.consts.foreignAssets.metadataDepositBase
  • summary: The basic amount of funds that must be reserved when adding metadata to your asset.

metadataDepositPerByte: u128​

  • interface: api.consts.foreignAssets.metadataDepositPerByte
  • summary: The additional funds that must be reserved for the number of bytes you store in your metadata.

removeItemsLimit: u32​

  • interface: api.consts.foreignAssets.removeItemsLimit

  • summary: Max number of items to destroy per destroy_accounts and destroy_approvals call.

    Must be configured to result in a weight that makes each call fit in a block.

stringLimit: u32​

  • interface: api.consts.foreignAssets.stringLimit
  • summary: The maximum length of a name or symbol stored on-chain.

messageQueue​

heapSize: u32​

  • interface: api.consts.messageQueue.heapSize

  • summary: The size of the page; this implies the maximum message size which can be sent.

    A good value depends on the expected message sizes, their weights, the weight that is available for processing them and the maximal needed message size. The maximal message size is slightly lower than this as defined by [MaxMessageLenOf].

idleMaxServiceWeight: Option<SpWeightsWeightV2Weight>​

  • interface: api.consts.messageQueue.idleMaxServiceWeight

  • summary: The maximum amount of weight (if any) to be used from remaining weight on_idle which should be provided to the message queue for servicing enqueued items on_idle. Useful for parachains to process messages at the same block they are received.

    If None, it will not call ServiceQueues::service_queues in on_idle.

maxStale: u32​

  • interface: api.consts.messageQueue.maxStale
  • summary: The maximum number of stale pages (i.e. of overweight messages) allowed before culling can happen. Once there are more stale pages than this, then historical pages may be dropped, even if they contain unprocessed overweight messages.

serviceWeight: Option<SpWeightsWeightV2Weight>​

  • interface: api.consts.messageQueue.serviceWeight

  • summary: The amount of weight (if any) which should be provided to the message queue for servicing enqueued items on_initialize.

    This may be legitimately None in the case that you will call ServiceQueues::service_queues manually or set [Self::IdleMaxServiceWeight] to have it run in on_idle.

multisig​

depositBase: u128​

  • interface: api.consts.multisig.depositBase

  • summary: The base amount of currency needed to reserve for creating a multisig execution or to store a dispatch call for later.

    This is held for an additional storage item whose value size is 4 + sizeof((BlockNumber, Balance, AccountId)) bytes and whose key size is 32 + sizeof(AccountId) bytes.

depositFactor: u128​

  • interface: api.consts.multisig.depositFactor

  • summary: The amount of currency needed per unit threshold when creating a multisig execution.

    This is held for adding 32 bytes more into a pre-existing storage value.

maxSignatories: u32​

  • interface: api.consts.multisig.maxSignatories
  • summary: The maximum amount of signatories allowed in the multisig.

nfts​

approvalsLimit: u32​

  • interface: api.consts.nfts.approvalsLimit
  • summary: The maximum approvals an item could have.

attributeDepositBase: u128​

  • interface: api.consts.nfts.attributeDepositBase
  • summary: The basic amount of funds that must be reserved when adding an attribute to an item.

collectionDeposit: u128​

  • interface: api.consts.nfts.collectionDeposit
  • summary: The basic amount of funds that must be reserved for collection.

depositPerByte: u128​

  • interface: api.consts.nfts.depositPerByte
  • summary: The additional funds that must be reserved for the number of bytes store in metadata, either "normal" metadata or attribute metadata.

features: u64​

  • interface: api.consts.nfts.features
  • summary: Disables some of pallet's features.

itemAttributesApprovalsLimit: u32​

  • interface: api.consts.nfts.itemAttributesApprovalsLimit
  • summary: The maximum attributes approvals an item could have.

itemDeposit: u128​

  • interface: api.consts.nfts.itemDeposit
  • summary: The basic amount of funds that must be reserved for an item.

keyLimit: u32​

  • interface: api.consts.nfts.keyLimit
  • summary: The maximum length of an attribute key.

maxAttributesPerCall: u32​

  • interface: api.consts.nfts.maxAttributesPerCall
  • summary: The max number of attributes a user could set per call.

maxDeadlineDuration: u32​

  • interface: api.consts.nfts.maxDeadlineDuration
  • summary: The max duration in blocks for deadlines.

maxTips: u32​

  • interface: api.consts.nfts.maxTips
  • summary: The max number of tips a user could send.

metadataDepositBase: u128​

  • interface: api.consts.nfts.metadataDepositBase
  • summary: The basic amount of funds that must be reserved when adding metadata to your item.

stringLimit: u32​

  • interface: api.consts.nfts.stringLimit
  • summary: The maximum length of data stored on-chain.

valueLimit: u32​

  • interface: api.consts.nfts.valueLimit
  • summary: The maximum length of an attribute value.

parachainSystem​

selfParaId: u32​

  • interface: api.consts.parachainSystem.selfParaId
  • summary: Returns the parachain ID we are running with.

poolAssets​

approvalDeposit: u128​

  • interface: api.consts.poolAssets.approvalDeposit
  • summary: The amount of funds that must be reserved when creating a new approval.

assetAccountDeposit: u128​

  • interface: api.consts.poolAssets.assetAccountDeposit
  • summary: The amount of funds that must be reserved for a non-provider asset account to be maintained.

assetDeposit: u128​

  • interface: api.consts.poolAssets.assetDeposit
  • summary: The basic amount of funds that must be reserved for an asset.

metadataDepositBase: u128​

  • interface: api.consts.poolAssets.metadataDepositBase
  • summary: The basic amount of funds that must be reserved when adding metadata to your asset.

metadataDepositPerByte: u128​

  • interface: api.consts.poolAssets.metadataDepositPerByte
  • summary: The additional funds that must be reserved for the number of bytes you store in your metadata.

removeItemsLimit: u32​

  • interface: api.consts.poolAssets.removeItemsLimit

  • summary: Max number of items to destroy per destroy_accounts and destroy_approvals call.

    Must be configured to result in a weight that makes each call fit in a block.

stringLimit: u32​

  • interface: api.consts.poolAssets.stringLimit
  • summary: The maximum length of a name or symbol stored on-chain.

proxy​

announcementDepositBase: u128​

  • interface: api.consts.proxy.announcementDepositBase

  • summary: The base amount of currency needed to reserve for creating an announcement.

    This is held when a new storage item holding a Balance is created (typically 16 bytes).

announcementDepositFactor: u128​

  • interface: api.consts.proxy.announcementDepositFactor

  • summary: The amount of currency needed per announcement made.

    This is held for adding an AccountId, Hash and BlockNumber (typically 68 bytes) into a pre-existing storage value.

maxPending: u32​

  • interface: api.consts.proxy.maxPending
  • summary: The maximum amount of time-delayed announcements that are allowed to be pending.

maxProxies: u32​

  • interface: api.consts.proxy.maxProxies
  • summary: The maximum amount of proxies allowed for a single account.

proxyDepositBase: u128​

  • interface: api.consts.proxy.proxyDepositBase

  • summary: The base amount of currency needed to reserve for creating a proxy.

    This is held for an additional storage item whose value size is sizeof(Balance) bytes and whose key size is sizeof(AccountId) bytes.

proxyDepositFactor: u128​

  • interface: api.consts.proxy.proxyDepositFactor

  • summary: The amount of currency needed per proxy added.

    This is held for adding 32 bytes plus an instance of ProxyType more into a pre-existing storage value. Thus, when configuring ProxyDepositFactor one should take into account 32 + proxy_type.encode().len() bytes of data.

system​

blockHashCount: u32​

  • interface: api.consts.system.blockHashCount
  • summary: Maximum number of block number to block hash mappings to keep (oldest pruned first).

blockLength: FrameSystemLimitsBlockLength​

  • interface: api.consts.system.blockLength
  • summary: The maximum length of a block (in bytes).

blockWeights: FrameSystemLimitsBlockWeights​

  • interface: api.consts.system.blockWeights
  • summary: Block & extrinsics weights: base values and limits.

dbWeight: SpWeightsRuntimeDbWeight​

  • interface: api.consts.system.dbWeight
  • summary: The weight of runtime database operations the runtime can invoke.

ss58Prefix: u16​

  • interface: api.consts.system.ss58Prefix

  • summary: The designated SS58 prefix of this chain.

    This replaces the "ss58Format" property declared in the chain spec. Reason is that the runtime should know about the prefix in order to make use of it as an identifier of the chain.

version: SpVersionRuntimeVersion​

  • interface: api.consts.system.version
  • summary: Get the chain's in-code version.

timestamp​

minimumPeriod: u64​

  • interface: api.consts.timestamp.minimumPeriod

  • summary: The minimum period between blocks.

    Be aware that this is different to the expected period that the block production apparatus provides. Your chosen consensus system will generally work with this to determine a sensible block time. For example, in the Aura pallet it will be double this period on default settings.

transactionPayment​

operationalFeeMultiplier: u8​

  • interface: api.consts.transactionPayment.operationalFeeMultiplier

  • summary: A fee multiplier for Operational extrinsics to compute "virtual tip" to boost their priority

    This value is multiplied by the final_fee to obtain a "virtual tip" that is later added to a tip component in regular priority calculations. It means that a Normal transaction can front-run a similarly-sized Operational extrinsic (with no tip), by including a tip value greater than the virtual tip.

    ``rust,ignore // For Normal` let priority = priority_calc(tip);

    // For Operational let virtual_tip = (inclusion_fee + tip) * OperationalFeeMultiplier; let priority = priority_calc(tip + virtual_tip); ```

    Note that since we use final_fee the multiplier applies also to the regular tip sent with the transaction. So, not only does the transaction get a priority bump based on the inclusion_fee, but we also amplify the impact of tips applied to Operational transactions.

uniques​

attributeDepositBase: u128​

  • interface: api.consts.uniques.attributeDepositBase
  • summary: The basic amount of funds that must be reserved when adding an attribute to an item.

collectionDeposit: u128​

  • interface: api.consts.uniques.collectionDeposit
  • summary: The basic amount of funds that must be reserved for collection.

depositPerByte: u128​

  • interface: api.consts.uniques.depositPerByte
  • summary: The additional funds that must be reserved for the number of bytes store in metadata, either "normal" metadata or attribute metadata.

itemDeposit: u128​

  • interface: api.consts.uniques.itemDeposit
  • summary: The basic amount of funds that must be reserved for an item.

keyLimit: u32​

  • interface: api.consts.uniques.keyLimit
  • summary: The maximum length of an attribute key.

metadataDepositBase: u128​

  • interface: api.consts.uniques.metadataDepositBase
  • summary: The basic amount of funds that must be reserved when adding metadata to your item.

stringLimit: u32​

  • interface: api.consts.uniques.stringLimit
  • summary: The maximum length of data stored on-chain.

valueLimit: u32​

  • interface: api.consts.uniques.valueLimit
  • summary: The maximum length of an attribute value.

utility​

batchedCallsLimit: u32​

  • interface: api.consts.utility.batchedCallsLimit
  • summary: The limit on the number of batched calls.

vesting​

maxVestingSchedules: u32​

  • interface: api.consts.vesting.maxVestingSchedules

minVestedTransfer: u128​

  • interface: api.consts.vesting.minVestedTransfer
  • summary: The minimum amount transferred to call vested_transfer.

xcmpQueue​

maxActiveOutboundChannels: u32​

  • interface: api.consts.xcmpQueue.maxActiveOutboundChannels

  • summary: Maximal number of outbound XCMP channels that can have messages queued at the same time.

    If this is reached, then no further messages can be sent to channels that do not yet have a message queued. This should be set to the expected maximum of outbound channels which is determined by [Self::ChannelInfo]. It is important to set this large enough, since otherwise the congestion control protocol will not work as intended and messages may be dropped. This value increases the PoV and should therefore not be picked too high. Governance needs to pay attention to not open more channels than this value.

maxInboundSuspended: u32​

  • interface: api.consts.xcmpQueue.maxInboundSuspended

  • summary: The maximum number of inbound XCMP channels that can be suspended simultaneously.

    Any further channel suspensions will fail and messages may get dropped without further notice. Choosing a high value (1000) is okay; the trade-off that is described in [InboundXcmpSuspended] still applies at that scale.

maxPageSize: u32​

  • interface: api.consts.xcmpQueue.maxPageSize

  • summary: The maximal page size for HRMP message pages.

    A lower limit can be set dynamically, but this is the hard-limit for the PoV worst case benchmarking. The limit for the size of a message is slightly below this, since some overhead is incurred for encoding the format.