Table of Contents
- RFC-0123: Introduce
:pending_codeas intermediate storage key for the runtime code @@ -245,11 +245,11 @@ For Polkadot/Kusama this means that also the parachain nodes need to be running
DepositReserveAsset, I
-
+
@@ -327,7 +327,7 @@ Following the same logic, the existing DepositReserveAsset, I
-
+
diff --git a/proposed/0123-pending-code-as-storage-location-for-runtime-upgrades.html b/approved/0123-pending-code-as-storage-location-for-runtime-upgrades.html
similarity index 78%
rename from proposed/0123-pending-code-as-storage-location-for-runtime-upgrades.html
rename to approved/0123-pending-code-as-storage-location-for-runtime-upgrades.html
index d9f9e33..3dfc873 100644
--- a/proposed/0123-pending-code-as-storage-location-for-runtime-upgrades.html
+++ b/approved/0123-pending-code-as-storage-location-for-runtime-upgrades.html
@@ -90,7 +90,7 @@
@@ -174,7 +174,7 @@
-
+
Table of Contents
- RFC-0123: Introduce
:pending_code as intermediate storage key for the runtime code
@@ -245,11 +245,11 @@ For Polkadot/Kusama this means that also the parachain nodes need to be running
diff --git a/approved/0125-xcm-asset-metadata.html b/approved/0125-xcm-asset-metadata.html
index f8c974c..65bac53 100644
--- a/approved/0125-xcm-asset-metadata.html
+++ b/approved/0125-xcm-asset-metadata.html
@@ -90,7 +90,7 @@
@@ -402,7 +402,7 @@ This RFC proposes to use the Undefined variant of a collection iden
The maximum size of a response is set to an arbitrary 16kiB. The responding side should make sure to conform to this limit. Given that fork_id is typically very small and that the only variable-length field is addrs, this is easily achieved by limiting the number of addresses.
Implementers should be aware that addrs might be very large, and are encouraged to limit the number of addrs to an implementation-defined value.
-Drawbacks
+Drawbacks
The peer_id and addrs fields are in theory not strictly needed, as the PeerId and addresses could be always equal to the PeerId and addresses of the node being registered as the provider and serving the response. However, the Cumulus implementation currently uses two different networking stacks, one of the parachain and one for the relay chain, using two separate PeerIds and addresses, and as such the PeerId and addresses of the other networking stack must be indicated. Asking them to use only one networking stack wouldn't feasible in a realistic time frame.
The values of the genesis_hash and fork_id fields cannot be verified by the requester and are expected to be unused at the moment. Instead, a client that desires connecting to a parachain is expected to obtain the genesis hash and fork ID of the parachain from the parachain chain specification. These fields are included in the networking protocol nonetheless in case an acceptable solution is found in the future, and in order to allow use cases such as discovering parachains in a not-strictly-trusted way.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
Because not all nodes want to be used as bootnodes, implementers are encouraged to provide a way to disable this mechanism. However, it is very much encouraged to leave this mechanism on by default for all parachain nodes.
This mechanism doesn't add or remove any security by itself, as it relies on existing mechanisms.
However, if the principle of chain specification bootnodes is entirely replaced with the mechanism described in this RFC (which is the objective), then it becomes important whether the mechanism in this RFC can be abused in order to make a parachain unreachable.
@@ -2434,22 +2368,22 @@ Furthermore, when a large number of providers (here, a provider is a bootnode) a
For this reason, an attacker can abuse this mechanism by randomly generating libp2p PeerIds until they find the 20 entries closest to the key representing the target parachain. They are then in control of the parachain bootnodes.
Because the key changes periodically and isn't predictable, and assuming that the Polkadot DHT is sufficiently large, it is not realistic for an attack like this to be maintained in the long term.
Furthermore, parachain clients are expected to cache a list of known good nodes on their disk. If the mechanism described in this RFC went down, it would only prevent new nodes from accessing the parachain, while clients that have connected before would not be affected.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
The DHT mechanism generally has a low overhead, especially given that publishing providers is done only every 24 hours.
Doing a Kademlia iterative query then sending a provider record shouldn't take more than around 50 kiB in total of bandwidth for the parachain bootnode.
Assuming 1000 parachain full nodes, the 20 Polkadot full nodes corresponding to a specific parachain will each receive a sudden spike of a few megabytes of networking traffic when the key rotates. Again, this is relatively negligible. If this becomes a problem, one can add a random delay before a parachain full node registers itself to be the provider of the key corresponding to BabeApi_next_epoch.
Maybe the biggest uncertainty is the traffic that the 20 Polkadot full nodes will receive from light clients that desire knowing the bootnodes of a parachain. Light clients are generally encouraged to cache the peers that they use between restarts, so they should only query these 20 Polkadot full nodes at their first initialization.
If this every becomes a problem, this value of 20 is an arbitrary constant that can be increased for more redundancy.
-Ergonomics
+Ergonomics
Irrelevant.
-Compatibility
+Compatibility
Irrelevant.
-Prior Art and References
+Prior Art and References
None.
-Unresolved Questions
+Unresolved Questions
While it fundamentally doesn't change much to this RFC, using BabeApi_currentEpoch and BabeApi_nextEpoch might be inappropriate. I'm not familiar enough with good practices within the runtime to have an opinion here. Should it be an entirely new pallet?
-Future Directions and Related Material
+Future Directions and Related Material
It is possible that in the future a client could connect to a parachain without having to rely on a trusted parachain specification.
Table of Contents
@@ -2482,9 +2416,9 @@ If this every becomes a problem, this value of 20 is an arbitrary constant that
Authors Pierre Krieger Summary
+Summary
Improve the networking messages that query storage items from the remote, in order to reduce the bandwidth usage and number of round trips of light clients.
-Motivation
+Motivation
Clients on the Polkadot peer-to-peer network can be divided into two categories: full nodes and light clients. So-called full nodes are nodes that store the content of the chain locally on their disk, while light clients are nodes that don't. In order to access for example the balance of an account, a full node can do a disk read, while a light client needs to send a network message to a full node and wait for the full node to reply with the desired value. This reply is in the form of a Merkle proof, which makes it possible for the light client to verify the exactness of the value.
Unfortunately, this network protocol is suffering from some issues:
@@ -2494,9 +2428,9 @@ If this every becomes a problem, this value of 20 is an arbitrary constant that
Once Polkadot and Kusama will have transitioned to state_version = 1, which modifies the format of the trie entries, it will be possible to generate Merkle proofs that contain only the hashes of values in the storage. Thanks to this, it is already possible to prove the existence of a key without sending its entire value (only its hash), or to prove that a value has changed or not between two blocks (by sending just their hashes).
Thus, the only reason why aforementioned issues exist is because the existing networking messages don't give the possibility for the querier to query this. This is what this proposal aims at fixing.
-Stakeholders
+Stakeholders
This is the continuation of https://github.com/w3f/PPPs/pull/10, which itself is the continuation of https://github.com/w3f/PPPs/pull/5.
-Explanation
+Explanation
The protobuf schema of the networking protocol can be found here: https://github.com/paritytech/substrate/blob/5b6519a7ff4a2d3cc424d78bc4830688f3b184c0/client/network/light/src/schema/light.v1.proto
The proposal is to modify this protocol in this way:
@@ -11,6 +11,7 @@ message Request {
@@ -2554,26 +2488,26 @@ An alternative could have been to specify the child_trie_info for e
Also note that child tries aren't considered as descendants of the main trie when it comes to the includeDescendants flag. In other words, if the request concerns the main trie, no content coming from child tries is ever sent back.
This protocol keeps the same maximum response size limit as currently exists (16 MiB). It is not possible for the querier to know in advance whether its query will lead to a reply that exceeds the maximum size. If the reply is too large, the replier should send back only a limited number (but at least one) of requested items in the proof. The querier should then send additional requests for the rest of the items. A response containing none of the requested items is invalid.
The server is allowed to silently discard some keys of the request if it judges that the number of requested keys is too high. This is in line with the fact that the server might truncate the response.
-Drawbacks
+Drawbacks
This proposal doesn't handle one specific situation: what if a proof containing a single specific item would exceed the response size limit? For example, if the response size limit was 1 MiB, querying the runtime code (which is typically 1.0 to 1.5 MiB) would be impossible as it's impossible to generate a proof less than 1 MiB. The response size limit is currently 16 MiB, meaning that no single storage item must exceed 16 MiB.
Unfortunately, because it's impossible to verify a Merkle proof before having received it entirely, parsing the proof in a streaming way is also not possible.
A way to solve this issue would be to Merkle-ize large storage items, so that a proof could include only a portion of a large storage item. Since this would require a change to the trie format, it is not realistically feasible in a short time frame.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
The main security consideration concerns the size of replies and the resources necessary to generate them. It is for example easily possible to ask for all keys and values of the chain, which would take a very long time to generate. Since responses to this networking protocol have a maximum size, the replier should truncate proofs that would lead to the response being too large. Note that it is already possible to send a query that would lead to a very large reply with the existing network protocol. The only thing that this proposal changes is that it would make it less complicated to perform such an attack.
Implementers of the replier side should be careful to detect early on when a reply would exceed the maximum reply size, rather than inconditionally generate a reply, as this could take a very large amount of CPU, disk I/O, and memory. Existing implementations might currently be accidentally protected from such an attack thanks to the fact that requests have a maximum size, and thus that the list of keys in the query was bounded. After this proposal, this accidental protection would no longer exist.
Malicious server nodes might truncate Merkle proofs even when they don't strictly need to, and it is not possible for the client to (easily) detect this situation. However, malicious server nodes can already do undesirable things such as throttle down their upload bandwidth or simply not respond. There is no need to handle unnecessarily truncated Merkle proofs any differently than a server simply not answering the request.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
It is unclear to the author of the RFC what the performance implications are. Servers are supposed to have limits to the amount of resources they use to respond to requests, and as such the worst that can happen is that light client requests become a bit slower than they currently are.
-Ergonomics
+Ergonomics
Irrelevant.
-Compatibility
+Compatibility
The prior networking protocol is maintained for now. The older version of this protocol could get removed in a long time.
-Prior Art and References
+Prior Art and References
None. This RFC is a clean-up of an existing mechanism.
-Unresolved Questions
+Unresolved Questions
None
-Future Directions and Related Material
+Future Directions and Related Material
The current networking protocol could be deprecated in a long time. Additionally, the current "state requests" protocol (used for warp syncing) could also be deprecated in favor of this one.
Table of Contents
@@ -2594,13 +2528,13 @@ Also note that child tries aren't considered as descendants of the main trie whe
Authors Jonas Gehrlein Summary
+Summary
The Polkadot UC will generate revenue from the sale of available Coretime. The question then arises: how should we handle these revenues? Broadly, there are two reasonable paths – burning the revenue and thereby removing it from total issuance or divert it to the Treasury. This Request for Comment (RFC) presents arguments favoring burning as the preferred mechanism for handling revenues from Coretime sales.
-Motivation
+Motivation
How to handle the revenue accrued from Coretime sales is an important economic question that influences the value of DOT and should be properly discussed before deciding for either of the options. Now is the best time to start this discussion.
-Stakeholders
+Stakeholders
Polkadot DOT token holders.
-Explanation
+Explanation
This RFC discusses potential benefits of burning the revenue accrued from Coretime sales instead of diverting them to Treasury. Here are the following arguments for it.
It's in the interest of the Polkadot community to have a consistent and predictable Treasury income, because volatility in the inflow can be damaging, especially in situations when it is insufficient. As such, this RFC operates under the presumption of a steady and sustainable Treasury income flow, which is crucial for the Polkadot community's stability. The assurance of a predictable Treasury income, as outlined in a prior discussion here, or through other equally effective measures, serves as a baseline assumption for this argument.
Consequently, we need not concern ourselves with this particular issue here. This naturally begs the question - why should we introduce additional volatility to the Treasury by aligning it with the variable Coretime sales? It's worth noting that Coretime revenues often exhibit an inverse relationship with periods when Treasury spending should ideally be ramped up. During periods of low Coretime utilization (indicated by lower revenue), Treasury should spend more on projects and endeavours to increase the demand for Coretime. This pattern underscores that Coretime sales, by their very nature, are an inconsistent and unpredictable source of funding for the Treasury. Given the importance of maintaining a steady and predictable inflow, it's unnecessary to rely on another volatile mechanism. Some might argue that we could have both: a steady inflow (from inflation) and some added bonus from Coretime sales, but burning the revenue would offer further benefits as described below.
@@ -2643,13 +2577,13 @@ Also note that child tries aren't considered as descendants of the main trie whe
Authors Joe Petrowski Summary
+Summary
Since the introduction of the Collectives parachain, many groups have expressed interest in forming
new -- or migrating existing groups into -- on-chain collectives. While adding a new collective is
relatively simple from a technical standpoint, the Fellowship will need to merge new pallets into
the Collectives parachain for each new collective. This RFC proposes a means for the network to
ratify a new collective, thus instructing the Fellowship to instate it in the runtime.
-Motivation
+Motivation
Many groups have expressed interest in representing collectives on-chain. Some of these include:
- Parachain technical fellowship (new)
@@ -2665,12 +2599,12 @@ path to having its collective accepted on-chain as part of the protocol. Accepta
the Fellowship to include the new collective with a given initial configuration into the runtime.
However, the network, not the Fellowship, should ultimately decide which collectives are in the
interest of the network.
-Stakeholders
+Stakeholders
- Polkadot stakeholders who would like to organize on-chain.
- Technical Fellowship, in its role of maintaining system runtimes.
-Explanation
+Explanation
The group that wishes to operate an on-chain collective should publish the following information:
- Charter, including the collective's mandate and how it benefits Polkadot. This would be similar
@@ -2704,22 +2638,22 @@ Fellowship would help them identify the pallet indices associated with a given c
or not the Fellowship member agrees with removal.
Collective removal may also come with other governance calls, for example voiding any scheduled
Treasury spends that would fund the given collective.
-Drawbacks
+Drawbacks
Passing a Root origin referendum is slow. However, given the network's investment (in terms of code
maintenance and salaries) in a new collective, this is an appropriate step.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
No impacts.
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
Generally all new collectives will be in the Collectives parachain. Thus, performance impacts
should strictly be limited to this parachain and not affect others. As the majority of logic for
collectives is generalized and reusable, we expect most collectives to be instances of similar
subsets of modules. That is, new collectives should generally be compatible with UIs and other
services that provide collective-related functionality, with little modifications to support new
ones.
-Prior Art and References
+Prior Art and References
The launch of the Technical Fellowship, see the
initial forum post.
-Unresolved Questions
+Unresolved Questions
None at this time.
Table of Contents
@@ -2756,13 +2690,13 @@ ones.
Authors Oliver Tale-Yazdi Summary
+Summary
Introduces breaking changes to the Core runtime API by letting Core::initialize_block return an enum. The versions of Core is bumped from 4 to 5.
-Motivation
+Motivation
The main feature that motivates this RFC are Multi-Block-Migrations (MBM); these make it possible to split a migration over multiple blocks.
Further it would be nice to not hinder the possibility of implementing a new hook poll, that runs at the beginning of the block when there are no MBMs and has access to AllPalletsWithSystem. This hook can then be used to replace the use of on_initialize and on_finalize for non-deadline critical logic.
In a similar fashion, it should not hinder the future addition of a System::PostInherents callback that always runs after all inherents were applied.
-Stakeholders
+Stakeholders
- Substrate Maintainers: They have to implement this, including tests, audit and
maintenance burden.
@@ -2770,7 +2704,7 @@ maintenance burden.
- Polkadot Parachain Teams: They have to adapt to the breaking changes but then eventually have
multi-block migrations available.
-Explanation
+Explanation
Core::initialize_block
This runtime API function is changed from returning () to ExtrinsicInclusionMode:
fn initialize_block(header: &<Block as BlockT>::Header)
@@ -2791,23 +2725,23 @@ multi-block migrations available.
1. Multi-Block-Migrations: The runtime is being put into lock-down mode for the duration of the migration process by returning OnlyInherents from initialize_block. This ensures that no user provided transaction can interfere with the migration process. It is absolutely necessary to ensure this, otherwise a transaction could call into un-migrated storage and violate storage invariants.
2. poll is possible by using apply_extrinsic as entry-point and not hindered by this approach. It would not be possible to use a pallet inherent like System::last_inherent to achieve this for two reasons: First is that pallets do not have access to AllPalletsWithSystem which is required to invoke the poll hook on all pallets. Second is that the runtime does currently not enforce an order of inherents.
3. System::PostInherents can be done in the same manner as poll.
-Drawbacks
+Drawbacks
The previous drawback of cementing the order of inherents has been addressed and removed by redesigning the approach. No further drawbacks have been identified thus far.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
The new logic of initialize_block can be tested by checking that the block-builder will skip transactions when OnlyInherents is returned.
Security: n/a
Privacy: n/a
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
The performance overhead is minimal in the sense that no clutter was added after fulfilling the
requirements. The only performance difference is that initialize_block also returns an enum that needs to be passed through the WASM boundary. This should be negligible.
-Ergonomics
+Ergonomics
The new interface allows for more extensible runtime logic. In the future, this will be utilized for
multi-block-migrations which should be a huge ergonomic advantage for parachain developers.
-Compatibility
+Compatibility
The advice here is OPTIONAL and outside of the RFC. To not degrade
user experience, it is recommended to ensure that an updated node can still import historic blocks.
-Prior Art and References
+Prior Art and References
The RFC is currently being implemented in polkadot-sdk#1781 (formerly substrate#14275). Related issues and merge
requests:
@@ -2817,14 +2751,14 @@ transactions
- There is no module hook after inherents and before
transactions
-Unresolved Questions
+Unresolved Questions
Please suggest a better name for BlockExecutiveMode. We already tried: RuntimeExecutiveMode,
ExtrinsicInclusionMode. The names of the modes Normal and Minimal were also called
AllExtrinsics and OnlyInherents, so if you have naming preferences; please post them.
=> renamed to ExtrinsicInclusionMode
Is post_inherents more consistent instead of last_inherent? Then we should change it.
=> renamed to last_inherent
-Future Directions and Related Material
+Future Directions and Related Material
The long-term future here is to move the block building logic into the runtime. Currently there is a tight dance between the block author and the runtime; the author has to call into different runtime functions in quick succession and exact order. Any misstep causes the block to be invalid.
This can be unified and simplified by moving both parts into the runtime.
@@ -2861,14 +2795,14 @@ This can be unified and simplified by moving both parts into the runtime.
Authors Bryan Chen Summary
+Summary
This RFC proposes a set of changes to the parachain lock mechanism. The goal is to allow a parachain manager to self-service the parachain without root track governance action.
This is achieved by remove existing lock conditions and only lock a parachain when:
- A parachain manager explicitly lock the parachain
- OR a parachain block is produced successfully
-Motivation
+Motivation
The manager of a parachain has permission to manage the parachain when the parachain is unlocked. Parachains are by default locked when onboarded to a slot. This requires the parachain wasm/genesis must be valid, otherwise a root track governance action on relaychain is required to update the parachain.
The current reliance on root track governance actions for managing parachains can be time-consuming and burdensome. This RFC aims to address this technical difficulty by allowing parachain managers to take self-service actions, rather than relying on general public voting.
The key scenarios this RFC seeks to improve are:
@@ -2887,12 +2821,12 @@ This can be unified and simplified by moving both parts into the runtime.
A parachain SHOULD be locked when it successfully produced the first block.
A parachain manager MUST be able to perform lease swap without having a running parachain.
-Stakeholders
+Stakeholders
- Parachain teams
- Parachain users
-Explanation
+Explanation
Status quo
A parachain can either be locked or unlocked3. With parachain locked, the parachain manager does not have any privileges. With parachain unlocked, the parachain manager can perform following actions with the paras_registrar pallet:
@@ -2932,31 +2866,31 @@ This can be unified and simplified by moving both parts into the runtime.
- Parachain never produced a block. Including from expired leases.
- Parachain manager never explicitly lock the parachain.
-Drawbacks
+Drawbacks
Parachain locks are designed in such way to ensure the decentralization of parachains. If parachains are not locked when it should be, it could introduce centralization risk for new parachains.
For example, one possible scenario is that a collective may decide to launch a parachain fully decentralized. However, if the parachain is unable to produce block, the parachain manager will be able to replace the wasm and genesis without the consent of the collective.
It is considered this risk is tolerable as it requires the wasm/genesis to be invalid at first place. It is not yet practically possible to develop a parachain without any centralized risk currently.
Another case is that a parachain team may decide to use crowdloan to help secure a slot lease. Previously, creating a crowdloan will lock a parachain. This means crowdloan participants will know exactly the genesis of the parachain for the crowdloan they are participating. However, this actually providers little assurance to crowdloan participants. For example, if the genesis block is determined before a crowdloan is started, it is not possible to have onchain mechanism to enforce reward distributions for crowdloan participants. They always have to rely on the parachain team to fulfill the promise after the parachain is alive.
Existing operational parachains will not be impacted.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
The implementation of this RFC will be tested on testnets (Rococo and Westend) first.
An audit maybe required to ensure the implementation does not introduce unwanted side effects.
There is no privacy related concerns.
-Performance
+Performance
This RFC should not introduce any performance impact.
-Ergonomics
+Ergonomics
This RFC should improve the developer experiences for new and existing parachain teams
-Compatibility
+Compatibility
This RFC is fully compatibility with existing interfaces.
-Prior Art and References
+Prior Art and References
- Parachain Slot Extension Story: https://github.com/paritytech/polkadot/issues/4758
- Allow parachain to renew lease without actually run another parachain: https://github.com/paritytech/polkadot/issues/6685
- Always treat parachain that never produced block for a significant amount of time as unlocked: https://github.com/paritytech/polkadot/issues/7539
-Unresolved Questions
+Unresolved Questions
None at this stage.
-Future Directions and Related Material
+Future Directions and Related Material
This RFC is only intended to be a short term solution. Slots will be removed in future and lock mechanism is likely going to be replaced with a more generalized parachain manage & recovery system in future. Therefore long term impacts of this RFC are not considered.
1
https://github.com/paritytech/cumulus/issues/377
@@ -2990,19 +2924,19 @@ This can be unified and simplified by moving both parts into the runtime.
Authors @brenzi for Encointer Association, 8000 Zurich, Switzerland Summary
+Summary
Encointer is a system chain on Kusama since Jan 2022 and has been developed and maintained by the Encointer association. This RFC proposes to treat Encointer like any other system chain and include it in the fellowship repo with this PR.
-Motivation
+Motivation
Encointer does not seek to be in control of its runtime repository. As a decentralized system, the fellowship has a more suitable structure to maintain a system chain runtime repo than the Encointer association does.
Also, Encointer aims to update its runtime in batches with other system chains in order to have consistency for interoperability across system chains.
-Stakeholders
+Stakeholders
- Fellowship: Will continue to take upon them the review and auditing work for the Encointer runtime, but the process is streamlined with other system chains and therefore less time-consuming compared to the separate repo and CI process we currently have.
- Kusama Network: Tokenholders can easily see the changes of all system chains in one place.
- Encointer Association: Further decentralization of the Encointer Network necessities like devops.
- Encointer devs: Being able to work directly in the Fellowship runtimes repo to streamline and synergize with other developers.
-Explanation
+Explanation
Our PR has all details about our runtime and how we would move it into the fellowship repo.
Noteworthy: All Encointer-specific pallets will still be located in encointer's repo for the time being: https://github.com/encointer/pallets
It will still be the duty of the Encointer team to keep its runtime up to date and provide adequate test fixtures. Frequent dependency bumps with Polkadot releases would be beneficial for interoperability and could be streamlined with other system chains but that will not be a duty of fellowship. Whenever possible, all system chains could be upgraded jointly (including Encointer) with a batch referendum.
@@ -3011,17 +2945,17 @@ This can be unified and simplified by moving both parts into the runtime.
Encointer will publish all its crates crates.io
Encointer does not carry out external auditing of its runtime nor pallets. It would be beneficial but not a requirement from our side if Encointer could join the auditing process of other system chains.
-Drawbacks
+Drawbacks
Other than all other system chains, development and maintenance of the Encointer Network is mainly financed by the KSM Treasury and possibly the DOT Treasury in the future. Encointer is dedicated to maintaining its network and runtime code for as long as possible, but there is a dependency on funding which is not in the hands of the fellowship. The only risk in the context of funding, however, is that the Encointer runtime will see less frequent updates if there's less funding.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
No changes to the existing system are proposed. Only changes to how maintenance is organized.
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
No changes
-Prior Art and References
+Prior Art and References
Existing Encointer runtime repo
-Unresolved Questions
+Unresolved Questions
None identified
-Future Directions and Related Material
+Future Directions and Related Material
More info on Encointer: encointer.org
Table of Contents
@@ -3941,11 +3875,11 @@ other privacy-enhancing mechanisms to address this concern.
Authors Joe Petrowski, Gavin Wood Summary
+Summary
The Relay Chain contains most of the core logic for the Polkadot network. While this was necessary
prior to the launch of parachains and development of XCM, most of this logic can exist in
parachains. This is a proposal to migrate several subsystems into system parachains.
-Motivation
+Motivation
Polkadot's scaling approach allows many distinct state machines (known generally as parachains) to
operate with common guarantees about the validity and security of their state transitions. Polkadot
provides these common guarantees by executing the state transitions on a strict subset (a backing
@@ -3957,13 +3891,13 @@ blockspace) to the network.
By minimising state transition logic on the Relay Chain by migrating it into "system chains" -- a
set of parachains that, with the Relay Chain, make up the Polkadot protocol -- the Polkadot
Ubiquitous Computer can maximise its primary offering: secure blockspace.
-Stakeholders
+Stakeholders
- Parachains that interact with affected logic on the Relay Chain;
- Core protocol and XCM format developers;
- Tooling, block explorer, and UI developers.
-Explanation
+Explanation
The following pallets and subsystems are good candidates to migrate from the Relay Chain:
- Identity
@@ -4109,36 +4043,36 @@ sensible to rehearse a migration.
Staking is the subsystem most constrained by PoV limits. Ensuring that elections, payouts, session
changes, offences/slashes, etc. work in a parachain on Kusama -- with its larger validator set --
will give confidence to the chain's robustness on Polkadot.
-Drawbacks
+Drawbacks
These subsystems will have reduced resources in cores than on the Relay Chain. Staking in particular
may require some optimizations to deal with constraints.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
Standard audit/review requirements apply. More powerful multi-chain integration test tools would be
useful in developement.
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
Describe the impact of the proposal on the exposed functionality of Polkadot.
-Performance
+Performance
This is an optimization. The removal of public/user transactions on the Relay Chain ensures that its
primary resources are allocated to system performance.
-Ergonomics
+Ergonomics
This proposal alters very little for coretime users (e.g. parachain developers). Application
developers will need to interact with multiple chains, making ergonomic light client tools
particularly important for application development.
For existing parachains that interact with these subsystems, they will need to configure their
runtimes to recognize the new locations in the network.
-Compatibility
+Compatibility
Implementing this proposal will require some changes to pallet APIs and/or a pub-sub protocol.
Application developers will need to interact with multiple chains in the network.
-Prior Art and References
+Prior Art and References
-Unresolved Questions
+Unresolved Questions
There remain some implementation questions, like how to use balances for both Staking and
Governance. See, for example, Moving Staking off the Relay
Chain.
-Future Directions and Related Material
+Future Directions and Related Material
Ideally the Relay Chain becomes transactionless, such that not even balances are represented there.
With Staking and Governance off the Relay Chain, this is not an unreasonable next step.
With Identity on Polkadot, Kusama may opt to drop its People Chain.
@@ -4173,13 +4107,13 @@ With Staking and Governance off the Relay Chain, this is not an unreasonable nex
Authors Vedhavyas Singareddi Summary
+Summary
At the moment, we have system_version field on RuntimeVersion that derives which state version is used for the
Storage.
We have a use case where we want extrinsics root is derived using StateVersion::V1. Without defining a new field
under RuntimeVersion,
we would like to propose adding system_version that can be used to derive both storage and extrinsic state version.
-Motivation
+Motivation
Since the extrinsic state version is always StateVersion::V0, deriving extrinsic root requires full extrinsic data.
This would be problematic when we need to verify the extrinsics root if the extrinsic sizes are bigger. This problem is
further explored in https://github.com/polkadot-fellows/RFCs/issues/19
@@ -4191,11 +4125,11 @@ One of the main challenge here is some extrinsics could be big enough that this
included in the Consensus block due to Block's weight restriction.
If the extrinsic root is derived using StateVersion::V1, then we do not need to pass the full extrinsic data but
rather at maximum, 32 byte of extrinsic data.
-Stakeholders
+Stakeholders
- Technical Fellowship, in its role of maintaining system runtimes.
-Explanation
+Explanation
In order to use project specific StateVersion for extrinsic roots, we proposed
an implementation that introduced
parameter to frame_system::Config but that unfortunately did not feel correct.
@@ -4221,26 +4155,26 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
system_version: 1,
};
}
-Drawbacks
+Drawbacks
There should be no drawbacks as it would replace state_version with same behavior but documentation should be updated
so that chains know which system_version to use.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
AFAIK, should not have any impact on the security or privacy.
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
These changes should be compatible for existing chains if they use state_version value for system_verision.
-Performance
+Performance
I do not believe there is any performance hit with this change.
-Ergonomics
+Ergonomics
This does not break any exposed Apis.
-Compatibility
+Compatibility
This change should not break any compatibility.
-Prior Art and References
+Prior Art and References
We proposed introducing a similar change by introducing a
parameter to frame_system::Config but did not feel that
is the correct way of introducing this change.
-Unresolved Questions
+Unresolved Questions
I do not have any specific questions about this change at the moment.
-Future Directions and Related Material
+Future Directions and Related Material
IMO, this change is pretty self-contained and there won't be any future work necessary.
Table of Contents
@@ -4269,9 +4203,9 @@ is the correct way of introducing this change.
Authors Sebastian Kunert Summary
+Summary
This RFC proposes a new host function for parachains, storage_proof_size. It shall provide the size of the currently recorded storage proof to the runtime. Runtime authors can use the proof size to improve block utilization by retroactively reclaiming unused storage weight.
-Motivation
+Motivation
The number of extrinsics that are included in a parachain block is limited by two constraints: execution time and proof size. FRAME weights cover both concepts, and block-builders use them to decide how many extrinsics to include in a block. However, these weights are calculated ahead of time by benchmarking on a machine with reference hardware. The execution-time properties of the state-trie and its storage items are unknown at benchmarking time. Therefore, we make some assumptions about the state-trie:
- Trie Depth: We assume a trie depth to account for intermediary nodes.
@@ -4280,12 +4214,12 @@ is the correct way of introducing this change.
These pessimistic assumptions lead to an overestimation of storage weight, negatively impacting block utilization on parachains.
In addition, the current model does not account for multiple accesses to the same storage items. While these repetitive accesses will not increase storage-proof size, the runtime-side weight monitoring will account for them multiple times. Since the proof size is completely opaque to the runtime, we can not implement retroactive storage weight correction.
A solution must provide a way for the runtime to track the exact storage-proof size consumed on a per-extrinsic basis.
-Stakeholders
+Stakeholders
- Parachain Teams: They MUST include this host function in their runtime and node.
- Light-client Implementors: They SHOULD include this host function in their runtime and node.
-Explanation
+Explanation
This RFC proposes a new host function that exposes the storage-proof size to the runtime. As a result, runtimes can implement storage weight reclaiming mechanisms that improve block utilization.
This RFC proposes the following host function signature:
#![allow(unused)]
@@ -4293,14 +4227,14 @@ is the correct way of introducing this change.
fn ext_storage_proof_size_version_1() -> u64;
}
The host function MUST return an unsigned 64-bit integer value representing the current proof size. In block-execution and block-import contexts, this function MUST return the current size of the proof. To achieve this, parachain node implementors need to enable proof recording for block imports. In other contexts, this function MUST return 18446744073709551615 (u64::MAX), which represents disabled proof recording.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
Parachain nodes need to enable proof recording during block import to correctly implement the proposed host function. Benchmarking conducted with balance transfers has shown a performance reduction of around 0.6% when proof recording is enabled.
-Ergonomics
+Ergonomics
The host function proposed in this RFC allows parachain runtime developers to keep track of the proof size. Typical usage patterns would be to keep track of the overall proof size or the difference between subsequent calls to the host function.
-Compatibility
+Compatibility
Parachain teams will need to include this host function to upgrade.
-Prior Art and References
+Prior Art and References
- Pull Request including proposed host function: PoV Reclaim (Clawback) Node Side.
- Issue with discussion: [FRAME core] Clawback PoV Weights For Dispatchables
@@ -4354,12 +4288,12 @@ is the correct way of introducing this change.
Authors Aurora Poppyseed, Just_Luuuu, Viki Val, Joe Petrowski Summary
+Summary
This RFC proposes changing the current deposit requirements on the Polkadot and Kusama Asset Hub for
creating an NFT collection, minting an individual NFT, and lowering its corresponding metadata and
attribute deposits. The objective is to lower the barrier to entry for NFT creators, fostering a
more inclusive and vibrant ecosystem while maintaining network integrity and preventing spam.
-Motivation
+Motivation
The current deposit of 10 DOT for collection creation (along with 0.01 DOT for item deposit and 0.2
DOT for metadata and attribute deposits) on the Polkadot Asset Hub and 0.1 KSM on Kusama Asset Hub
presents a significant financial barrier for many NFT creators. By lowering the deposit
@@ -4376,7 +4310,7 @@ low.
- Deposits SHOULD be derived from
deposit function, adjusted by correspoding pricing mechansim.
-Stakeholders
+Stakeholders
- NFT Creators: Primary beneficiaries of the proposed change, particularly those who found the
current deposit requirements prohibitive.
@@ -4390,7 +4324,7 @@ collections, enhancing the overall ecosystem.
Previous discussions have been held within the Polkadot
Forum, with
artists expressing their concerns about the deposit amounts.
-Explanation
+Explanation
This RFC proposes a revision of the deposit constants in the configuration of the NFTs pallet on the
Polkadot Asset Hub. The new deposit amounts would be determined by a standard deposit formula.
As of v1.1.1, the Collection Deposit is 10 DOT and the Item Deposit is 0.01 DOT (see
@@ -4461,7 +4395,7 @@ application to avoid sudden rate changes, as in:
where the constant a moves the inflection to lower or higher x values, the constant b adjusts
the rate of the deposit increase, and the independent variable x is the number of collections or
items, depending on application.
-Drawbacks
+Drawbacks
Modifying deposit requirements necessitates a balanced assessment of the potential drawbacks.
Highlighted below are cogent points extracted from the discourse on the Polkadot Forum
conversation,
@@ -4490,22 +4424,22 @@ stakeholders wouldn't be much affected. As of date 9th January 2024 there are 42
Polkadot Asset Hub and 191 on Kusama Asset Hub with a relatively low volume.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
Security concerns
As noted above, state bloat is a security concern. In the case of abuse, governance could adapt by
increasing deposit rates and/or using forceDestroy on collections agreed to be spam.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
The primary performance consideration stems from the potential for state bloat due to increased
activity from lower deposit requirements. It's vital to monitor and manage this to avoid any
negative impact on the chain's performance. Strategies for mitigating state bloat, including
efficient data management and periodic reviews of storage requirements, will be essential.
-Ergonomics
+Ergonomics
The proposed change aims to enhance the user experience for artists, traders, and utilizers of
Kusama and Polkadot Asset Hubs, making Polkadot and Kusama more accessible and user-friendly.
-Compatibility
+Compatibility
The change does not impact compatibility as a redeposit function is already implemented.
-Unresolved Questions
+Unresolved Questions
If this RFC is accepted, there should not be any unresolved questions regarding how to adapt the
implementation of deposits for NFT collections.
Addendum
@@ -4593,11 +4527,11 @@ Polkadot and Kusama networks.
Authors Alin Dima Summary
+Summary
Propose a way of permuting the availability chunk indices assigned to validators, in the context of
recovering available data from systematic chunks, with the
purpose of fairly distributing network bandwidth usage.
-Motivation
+Motivation
Currently, the ValidatorIndex is always identical to the ChunkIndex. Since the validator array is only shuffled once
per session, naively using the ValidatorIndex as the ChunkIndex would pose an unreasonable stress on the first N/3
validators during an entire session, when favouring availability recovery from systematic chunks.
@@ -4605,9 +4539,9 @@ validators during an entire session, when favouring availability recovery from s
systematic availability chunks to different validators, based on the relay chain block and core.
The main purpose is to ensure fair distribution of network bandwidth usage for availability recovery in general and in
particular for systematic chunk holders.
-Stakeholders
+Stakeholders
Relay chain node core developers.
-Explanation
+Explanation
Systematic erasure codes
An erasure coding algorithm is considered systematic if it preserves the original unencoded data as part of the
resulting code.
@@ -4761,7 +4695,7 @@ struct (added in https://github.com/paritytech/polkadot-sdk/pull/2177Configuration::set_node_feature extrinsic. Once the feature is enabled and new configuration is live, the
validator->chunk mapping ceases to be a 1:1 mapping and systematic recovery may begin.
-Drawbacks
+Drawbacks
- Getting access to the
core_index that used to be occupied by a candidate in some parts of the dispute protocol is
very complicated (See appendix A). This RFC assumes that availability-recovery processes initiated during
@@ -4771,28 +4705,28 @@ mitigate this problem and will likely be needed in the future for CoreJam and/or
Related discussion about updating CandidateReceipt
- It's a breaking change that requires all validators and collators to upgrade their node version at least once.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
Extensive testing will be conducted - both automated and manual.
This proposal doesn't affect security or privacy.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
This is a necessary data availability optimisation, as reed-solomon erasure coding has proven to be a top consumer of
CPU time in polkadot as we scale up the parachain block size and number of availability cores.
With this optimisation, preliminary performance results show that CPU time used for reed-solomon coding/decoding can be
halved and total POV recovery time decrease by 80% for large POVs. See more
here.
-Ergonomics
+Ergonomics
Not applicable.
-Compatibility
+Compatibility
This is a breaking change. See upgrade path section above.
All validators and collators need to have upgraded their node versions before the feature will be enabled via a
governance call.
-Prior Art and References
+Prior Art and References
See comments on the tracking issue and the
in-progress PR
-Unresolved Questions
+Unresolved Questions
Not applicable.
-Future Directions and Related Material
+Future Directions and Related Material
This enables future optimisations for the performance of availability recovery, such as retrieving batched systematic
chunks from backers/approval-checkers.
Appendix A
@@ -4867,7 +4801,7 @@ dispute scenarios.
Authors Bastian Köcher Summary
+Summary
This RFC proposes to changes the SessionKeys::generate_session_keys runtime api interface. This runtime api is used by validator operators to
generate new session keys on a node. The public session keys are then registered manually on chain by the validator operator.
Before this RFC it was not possible by the on chain logic to ensure that the account setting the public session keys is also in
@@ -4875,7 +4809,7 @@ possession of the private session keys. To solve this the RFC proposes to pass t
registration on chain to generate_session_keys. Further this RFC proposes to change the return value of the generate_session_keys
function also to not only return the public session keys, but also the proof of ownership for the private session keys. The
validator operator will then need to send the public session keys and the proof together when registering new session keys on chain.
-Motivation
+Motivation
When submitting the new public session keys to the on chain logic there doesn't exist any verification of possession of the private session keys.
This means that users can basically register any kind of public session keys on chain. While the on chain logic ensures that there are
no duplicate keys, someone could try to prevent others from registering new session keys by setting them first. While this wouldn't bring
@@ -4883,13 +4817,13 @@ the "attacker" any kind of advantage, more like disadvantages (potenti
e.g. changing its session key in the event of a private session key leak.
After this RFC this kind of attack would not be possible anymore, because the on chain logic can verify that the sending account
is in ownership of the private session keys.
-Stakeholders
+Stakeholders
- Polkadot runtime implementors
- Polkadot node implementors
- Validator operators
-Explanation
+Explanation
We are first going to explain the proof format being used:
#![allow(unused)]
fn main() {
@@ -4923,31 +4857,31 @@ actual exported function signature looks like:
already gets the proof passed as Vec<u8>. This proof needs to be decoded to
the actual Proof type as explained above. The proof and the SCALE encoded
account_id of the sender are used to verify the ownership of the SessionKeys.
-Drawbacks
+Drawbacks
Validator operators need to pass the their account id when rotating their session keys in a node.
This will require updating some high level docs and making users familiar with the slightly changed ergonomics.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
Testing of the new changes only requires passing an appropriate owner for the current testing context.
The changes to the proof generation and verification got audited to ensure they are correct.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
The session key generation is an offchain process and thus, doesn't influence the performance of the
chain. Verifying the proof is done on chain as part of the transaction logic for setting the session keys.
The verification of the proof is a signature verification number of individual session keys times. As setting
the session keys is happening quite rarely, it should not influence the overall system performance.
-Ergonomics
+Ergonomics
The interfaces have been optimized to make it as easy as possible to generate the ownership proof.
-Compatibility
+Compatibility
Introduces a new version of the SessionKeys runtime api. Thus, nodes should be updated before
a runtime is enacted that contains these changes otherwise they will fail to generate session keys.
The RPC that exists around this runtime api needs to be updated to support passing the account id
and for returning the ownership proof alongside the public session keys.
UIs would need to be updated to support the new RPC and the changed on chain logic.
-Prior Art and References
+Prior Art and References
None.
-Unresolved Questions
+Unresolved Questions
None.
-Future Directions and Related Material
+Future Directions and Related Material
Substrate implementation of the RFC.
Table of Contents
@@ -4985,10 +4919,10 @@ and for returning the ownership proof alongside the public session keys.
Authors Joe Petrowski, Gavin Wood Summary
+Summary
The Fellowship Manifesto states that members should receive a monthly allowance on par with gross
income in OECD countries. This RFC proposes concrete amounts.
-Motivation
+Motivation
One motivation for the Technical Fellowship is to provide an incentive mechanism that can induct and
retain technical talent for the continued progress of the network.
In order for members to uphold their commitment to the network, they should receive support to
@@ -4998,12 +4932,12 @@ on par with a full-time job. Providing a livable wage to those making such contr
pragmatic to work full-time on Polkadot.
Note: Goals of the Fellowship, expectations for each Dan, and conditions for promotion and demotion
are all explained in the Manifesto. This RFC is only to propose concrete values for allowances.
-Stakeholders
+Stakeholders
- Fellowship members
- Polkadot Treasury
-Explanation
+Explanation
This RFC proposes agreeing on salaries relative to a single level, the III Dan. As such, changes to
the amount or asset used would only be on a single value, and all others would adjust relatively. A
III Dan is someone whose contributions match the expectations of a full-time individual contributor.
@@ -5063,19 +4997,19 @@ other hand, more people will likely join the Fellowship in the coming years.
Updates
Updates to these levels, whether relative ratios, the asset used, or the amount, shall be done via
RFC.
-Drawbacks
+Drawbacks
By not using DOT for payment, the protocol relies on the stability of other assets and the ability
to acquire them. However, the asset of choice can be changed in the future.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
N/A.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
N/A
-Ergonomics
+Ergonomics
N/A
-Compatibility
+Compatibility
N/A
-Prior Art and References
+Prior Art and References
- The Polkadot Fellowship
Manifesto
@@ -5083,7 +5017,7 @@ Manifesto
- Indeed: Average Salary for Engineers, United
States
-Unresolved Questions
+Unresolved Questions
None at present.
Table of Contents
@@ -5116,11 +5050,11 @@ States
Authors Pierre Krieger Summary
+Summary
When two peers connect to each other, they open (amongst other things) a so-called "notifications protocol" substream dedicated to gossiping transactions to each other.
Each notification on this substream currently consists in a SCALE-encoded Vec<Transaction> where Transaction is defined in the runtime.
This RFC proposes to modify the format of the notification to become (Compact(1), Transaction). This maintains backwards compatibility, as this new format decodes as a Vec of length equal to 1.
-Motivation
+Motivation
There exists three motivations behind this change:
-
@@ -5133,9 +5067,9 @@ States
It makes the implementation way more straight-forward by not having to repeat code related to back-pressure. See explanations below.
-Stakeholders
+Stakeholders
Low-level developers.
-Explanation
+Explanation
To give an example, if you send one notification with three transactions, the bytes that are sent on the wire are:
concat(
leb128(total-size-in-bytes-of-the-rest),
@@ -5155,23 +5089,23 @@ A SCALE-compact encoded 1 is one byte of value 4. In o
This is equivalent to forcing the Vec<Transaction> to always have a length of 1, and I expect the Substrate implementation to simply modify the sending side to add a for loop that sends one notification per item in the Vec.
As explained in the motivation section, this allows extracting scale(transaction) items without having to know how to decode them.
By "flattening" the two-steps hierarchy, an implementation only needs to back-pressure individual notifications rather than back-pressure notifications and transactions within notifications.
-Drawbacks
+Drawbacks
This RFC chooses to maintain backwards compatibility at the cost of introducing a very small wart (the Compact(1)).
An alternative could be to introduce a new version of the transactions notifications protocol that sends one Transaction per notification, but this is significantly more complicated to implement and can always be done later in case the Compact(1) is bothersome.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
Irrelevant.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
Irrelevant.
-Ergonomics
+Ergonomics
Irrelevant.
-Compatibility
+Compatibility
The change is backwards compatible if done in two steps: modify the sender to always send one transaction per notification, then, after a while, modify the receiver to enforce the new format.
-Prior Art and References
+Prior Art and References
Irrelevant.
-Unresolved Questions
+Unresolved Questions
None.
-Future Directions and Related Material
+Future Directions and Related Material
None. This is a simple isolated change.
Table of Contents
@@ -5211,20 +5145,20 @@ This is equivalent to forcing the Vec<Transaction> to always
Authors Pierre Krieger Summary
+Summary
This RFC proposes to make the mechanism of RFC #8 more generic by introducing the concept of "capabilities".
Implementations can implement certain "capabilities", such as serving old block headers or being a parachain bootnode.
The discovery mechanism of RFC #8 is extended to be able to discover nodes of specific capabilities.
-Motivation
+Motivation
The Polkadot peer-to-peer network is made of nodes. Not all these nodes are equal. Some nodes store only the headers of recent blocks, some nodes store all the block headers and bodies since the genesis, some nodes store the storage of all blocks since the genesis, and so on.
It is currently not possible to know ahead of time (without connecting to it and asking) which nodes have which data available, and it is not easily possible to build a list of nodes that have a specific piece of data available.
If you want to download for example the header of block 500, you have to connect to a randomly-chosen node, ask it for block 500, and if it says that it doesn't have the block, disconnect and try another randomly-chosen node.
In certain situations such as downloading the storage of old blocks, nodes that have the information are relatively rare, and finding through trial and error a node that has the data can take a long time.
This RFC attempts to solve this problem by giving the possibility to build a list of nodes that are capable of serving specific data.
-Stakeholders
+Stakeholders
Low-level client developers.
People interested in accessing the archive of the chain.
-Explanation
+Explanation
Reading RFC #8 first might help with comprehension, as this RFC is very similar.
Please keep in mind while reading that everything below applies for both relay chains and parachains, except mentioned otherwise.
Capabilities
@@ -5260,30 +5194,30 @@ If blocks pruning is enabled and the chain is a relay chain, then Substrate unfo
Implementations that have the head of the chain provider capability do not register themselves as providers, but instead are the nodes that participate in the main DHT. In other words, they are the nodes that serve requests of the /<genesis_hash>/kad protocol.
Any implementation that isn't a head of the chain provider (read: light clients) must not participate in the main DHT. This is already presently the case.
Implementations must not participate in the main DHT if they don't fulfill the capability yet. For example, a node that is still in the process of warp syncing must not participate in the main DHT. However, assuming that warp syncing doesn't last more than a few seconds, it is acceptable to ignore this requirement in order to avoid complicating implementations too much.
-Drawbacks
+Drawbacks
None that I can see.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
The content of this section is basically the same as the one in RFC 8.
This mechanism doesn't add or remove any security by itself, as it relies on existing mechanisms.
Due to the way Kademlia works, it would become the responsibility of the 20 Polkadot nodes whose sha256(peer_id) is closest to the key (described in the explanations section) to store the list of nodes that have specific capabilities.
Furthermore, when a large number of providers are registered, only the providers closest to the key are kept, up to a certain implementation-defined limit.
For this reason, an attacker can abuse this mechanism by randomly generating libp2p PeerIds until they find the 20 entries closest to the key representing the target capability. They are then in control of the list of nodes with that capability. While doing this can in no way be actually harmful, it could lead to eclipse attacks.
Because the key changes periodically and isn't predictable, and assuming that the Polkadot DHT is sufficiently large, it is not realistic for an attack like this to be maintained in the long term.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
The DHT mechanism generally has a low overhead, especially given that publishing providers is done only every 24 hours.
Doing a Kademlia iterative query then sending a provider record shouldn't take more than around 50 kiB in total of bandwidth for the parachain bootnode.
Assuming 1000 nodes with a specific capability, the 20 Polkadot full nodes corresponding to that capability will each receive a sudden spike of a few megabytes of networking traffic when the key rotates. Again, this is relatively negligible. If this becomes a problem, one can add a random delay before a node registers itself to be the provider of the key corresponding to BabeApi_next_epoch.
Maybe the biggest uncertainty is the traffic that the 20 Polkadot full nodes will receive from light clients that desire knowing the nodes with a capability. If this every becomes a problem, this value of 20 is an arbitrary constant that can be increased for more redundancy.
-Ergonomics
+Ergonomics
Irrelevant.
-Compatibility
+Compatibility
Irrelevant.
-Prior Art and References
+Prior Art and References
Unknown.
-Unresolved Questions
+Unresolved Questions
While it fundamentally doesn't change much to this RFC, using BabeApi_currentEpoch and BabeApi_nextEpoch might be inappropriate. I'm not familiar enough with good practices within the runtime to have an opinion here. Should it be an entirely new pallet?
-Future Directions and Related Material
+Future Directions and Related Material
This RFC would make it possible to reliably discover archive nodes, which would make it possible to reliably send archive node requests, something that isn't currently possible. This could solve the problem of finding archive RPC node providers by migrating archive-related request to using the native peer-to-peer protocol rather than JSON-RPC.
If we ever decide to break backwards compatibility, we could divide the "history" and "archive" capabilities in two, between nodes capable of serving older blocks and nodes capable of serving newer blocks.
We could even add to the peer-to-peer network nodes that are only capable of serving older blocks (by reading from a database) but do not participate in the head of the chain, and that just exist for historical purposes.
@@ -5332,12 +5266,12 @@ We could even add to the peer-to-peer network nodes that are only capable of ser
Authors Zondax AG, Parity Technologies Summary
+Summary
To interact with chains in the Polkadot ecosystem it is required to know how transactions are encoded and how to read state. For doing this, Polkadot-SDK, the framework used by most of the chains in the Polkadot ecosystem, exposes metadata about the runtime to the outside. UIs, wallets, and others can use this metadata to interact with these chains. This makes the metadata a crucial piece of the transaction encoding as users are relying on the interacting software to encode the transactions in the correct format.
It gets even more important when the user signs the transaction in an offline wallet, as the device by its nature cannot get access to the metadata without relying on the online wallet to provide it. This makes it so that the offline wallet needs to trust an online party, deeming the security assumptions of the offline devices, mute.
This RFC proposes a way for offline wallets to leverage metadata, within the constraints of these. The design idea is that the metadata is chunked and these chunks are put into a merkle tree. The root hash of this merkle tree represents the metadata. The offline wallets can use the root hash to decode transactions by getting proofs for the individual chunks of the metadata. This root hash is also included in the signed data of the transaction (but not sent as part of the transaction). The runtime is then including its known metadata root hash when verifying the transaction. If the metadata root hash known by the runtime differs from the one that the offline wallet used, it very likely means that the online wallet provided some fake data and the verification of the transaction fails.
Users depend on offline wallets to correctly display decoded transactions before signing. With merkleized metadata, they can be assured of the transaction's legitimacy, as incorrect transactions will be rejected by the runtime.
-Motivation
+Motivation
Polkadot's innovative design (both relay chain and parachains) present the ability to developers to upgrade their network as frequently as they need. These systems manage to have integrations working after the upgrades with the help of FRAME Metadata. This Metadata, which is in the order of half a MiB for most Polkadot-SDK chains, completely describes chain interfaces and properties. Securing this metadata is key for users to be able to interact with the Polkadot-SDK chain in the expected way.
On the other hand, offline wallets provide a secure way for Blockchain users to hold their own keys (some do a better job than others). These devices seldomly get upgraded, usually account for one particular network and hold very small internal memories. Currently in the Polkadot ecosystem there is no secure way of having these offline devices know the latest Metadata of the Polkadot-SDK chain they are interacting with. This results in a plethora of similar yet slightly different offline wallets for all different Polkadot-SDK chains, as well as the impediment of keeping these regularly updated, thus not fully leveraging Polkadot-SDK’s unique forkless upgrade feature.
The two main reasons why this is not possible today are:
@@ -5364,14 +5298,14 @@ We could even add to the peer-to-peer network nodes that are only capable of ser
Chunks handling mechanism SHOULD support chunks being sent in any order without memory utilization overhead;
Unused enum variants MUST be stripped (this has great impact on transmitted metadata size; examples: era enum, enum with all calls for call batching).
-Stakeholders
+Stakeholders
- Runtime implementors
- UI/wallet implementors
- Offline wallet implementors
The idea for this RFC was brought up by runtime implementors and was extensively discussed with offline wallet implementors. It was designed in such a way that it can work easily with the existing offline wallet solutions in the Polkadot ecosystem.
-Explanation
+Explanation
The FRAME metadata provides a wide range of information about a FRAME based runtime. It contains information about the pallets, the calls per pallet, the storage entries per pallet, runtime APIs, and type information about most of the types that are used in the runtime. For decoding extrinsics on an offline wallet, what is mainly required is type information. Most of the other information in the FRAME metadata is actually not required for decoding extrinsics and thus it can be removed. Therefore, the following is a proposal on a custom representation of the metadata and how this custom metadata is chunked, ensuring that only the needed chunks required for decoding a particular extrinsic are sent to the offline wallet. The necessary information to transform the FRAME metadata type information into the type information presented in this RFC will be provided. However, not every single detail on how to convert from FRAME metadata into the RFC type information is described.
First, the MetadataDigest is introduced. After that, ExtrinsicMetadata is covered and finally the actual format of the type information. Then pruning of unrelated type information is covered and how to generate the TypeRefs. In the latest step, merkle tree calculation is explained.
Metadata digest
@@ -5642,23 +5576,23 @@ nodes: [[[2, 3], [4, 5]], [0, 1]]
Included in the extrinsic is u8, the "mode". The mode is either 0 which means to not include the metadata hash in the signed data or the mode is 1 to include the metadata hash in V1.
Included in the signed data is an Option<[u8; 32]>. Depending on the mode the value is either None or Some(metadata_hash).
-Drawbacks
+Drawbacks
The chunking may not be the optimal case for every kind of offline wallet.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
All implementations are required to strictly follow the RFC to generate the metadata hash. This includes which hash function to use and how to construct the metadata types tree. So, all implementations are following the same security criteria. As the chains will calculate the metadata hash at compile time, the build process needs to be trusted. However, this is already a solved problem in the Polkadot ecosystem by using reproducible builds. So, anyone can rebuild a chain runtime to ensure that a proposal is actually containing the changes as advertised.
Implementations can also be tested easily against each other by taking some metadata and ensuring that they all come to the same metadata hash.
Privacy of users should also not be impacted. This assumes that wallets will generate the metadata hash locally and don't leak any information to third party services about which chunks a user will send to their offline wallet. Besides that, there is no leak of private information as getting the raw metadata from the chain is an operation that is done by almost everyone.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
There should be no measurable impact on performance to Polkadot or any other chain using this feature. The metadata root hash is calculated at compile time and at runtime it is optionally used when checking the signature of a transaction. This means that at runtime no performance heavy operations are done.
Ergonomics & Compatibility
The proposal alters the way a transaction is built, signed, and verified. So, this imposes some required changes to any kind of developer who wants to construct transactions for Polkadot or any chain using this feature. As the developer can pass 0 for disabling the verification of the metadata root hash, it can be easily ignored.
-Prior Art and References
+Prior Art and References
RFC 46 produced by the Alzymologist team is a previous work reference that goes in this direction as well.
On other ecosystems, there are other solutions to the problem of trusted signing. Cosmos for example has a standardized way of transforming a transaction into some textual representation and this textual representation is included in the signed data. Basically achieving the same as what the RFC proposes, but it requires that for every transaction applied in a block, every node in the network always has to generate this textual representation to ensure the transaction signature is valid.
-Unresolved Questions
+Unresolved Questions
None.
-Future Directions and Related Material
+Future Directions and Related Material
- Does it work with all kind of offline wallets?
- Generic types currently appear multiple times in the metadata with each instantiation. It could be may be useful to have generic type only once in the metadata and declare the generic parameters at their instantiation.
@@ -5696,20 +5630,20 @@ nodes: [[[2, 3], [4, 5]], [0, 1]]
Authors George Pisaltu Summary
+Summary
This RFC proposes a change to the extrinsic format to incorporate a new transaction type, the "general" transaction.
-Motivation
+Motivation
"General" transactions, a new type of transaction that this RFC aims to support, are transactions which obey the runtime's extensions and have according extension data yet do not have hard-coded signatures. They are first described in Extrinsic Horizon and supported in 3685. They enable users to authorize origins in new, more flexible ways (e.g. ZK proofs, mutations over pre-authenticated origins). As of now, all transactions are limited to the account signing model for origin authorization and any additional origin changes happen in extrinsic logic, which cannot leverage the validation process of extensions.
An example of a use case for such an extension would be sponsoring the transaction fee for some other user. A new extension would be put in place to verify that a part of the initial payload was signed by the author under who the extrinsic should run and change the origin, but the payment for the whole transaction should be handled under a sponsor's account. A POC for this can be found in 3712.
The new "general" transaction type would coexist with both current transaction types for a while and, therefore, the current number of supported transaction types, capped at 2, is insufficient. A new extrinsic type must be introduced alongside the current signed and unsigned types. Currently, an encoded extrinsic's first byte indicate the type of extrinsic using the most significant bit - 0 for unsigned, 1 for signed - and the 7 following bits indicate the extrinsic format version, which has been equal to 4 for a long time.
By taking one bit from the extrinsic format version encoding, we can support 2 additional extrinsic types while also having a minimal impact on our capability to extend and change the extrinsic format in the future.
-Stakeholders
+Stakeholders
- Runtime users
- Runtime devs
- Wallet devs
-Explanation
+Explanation
An extrinsic is currently encoded as one byte to identify the extrinsic type and version. This RFC aims to change the interpretation of this byte regarding the reserved bits for the extrinsic type and version. In the following explanation, bits represented using T make up the extrinsic type and bits represented using V make up the extrinsic version.
Currently, the bit allocation within the leading encoded byte is 0bTVVV_VVVV. In practice in the Polkadot ecosystem, the leading byte would be 0bT000_0100 as the version has been equal to 4 for a long time.
This RFC proposes for the bit allocation to change to 0bTTVV_VVVV. As a result, the extrinsic format version will be bumped to 5 and the extrinsic type bit representation would change as follows:
@@ -5720,23 +5654,23 @@ nodes: [[[2, 3], [4, 5]], [0, 1]]
11 reserved Drawbacks
+Drawbacks
This change would reduce the maximum possible transaction version from the current 127 to 63. In order to bypass the new, lower limit, the extrinsic format would have to change again.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
There is no impact on testing, security or privacy.
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
This change would allow Polkadot to support new types of transactions, with the specific "general" transaction type in mind at the time of writing this proposal.
-Performance
+Performance
There is no performance impact.
-Ergonomics
+Ergonomics
The impact to developers and end-users is minimal as it would just be a bitmask update on their part for parsing the extrinsic type along with the version.
-Compatibility
+Compatibility
This change breaks backwards compatiblity because any transaction that is neither signed nor unsigned, but a new transaction type, would be interpreted as having a future extrinsic format version.
-Prior Art and References
+Prior Art and References
The original design was originally proposed in the TransactionExtension PR, which is also the motivation behind this effort.
-Unresolved Questions
+Unresolved Questions
None.
-Future Directions and Related Material
+Future Directions and Related Material
Following this change, the "general" transaction type will be introduced as part of the Extrinsic Horizon effort, which will shape future work.
Table of Contents
@@ -5769,16 +5703,16 @@ nodes: [[[2, 3], [4, 5]], [0, 1]]
Authors Alex Gheorghe (alexggh) Summary
+Summary
Extend the DHT authority discovery records with a signed creation time, so that nodes can determine which record is newer and always decide to prefer the newer records to the old ones.
-Motivation
+Motivation
Currently, we use the Kademlia DHT for storing records regarding the p2p address of an authority discovery key, the problem is that if the nodes decide to change its PeerId/Network key it will publish a new record, however because of the distributed and replicated nature of the DHT there is no way to tell which record is newer so both old PeerId and the new PeerId will live in the network until the old one expires(36h), that creates all sort of problem and leads to the node changing its address not being properly connected for up to 36h.
After this RFC, nodes are extended to decide to keep the new record and propagate the new record to nodes that have the old record stored, so in the end all the nodes will converge faster to the new record(in the order of minutes, not 36h)
Implementation of the rfc: https://github.com/paritytech/polkadot-sdk/pull/3786.
Current issue without this enhacement: https://github.com/paritytech/polkadot-sdk/issues/3673
-Stakeholders
+Stakeholders
Polkadot node developers.
-Explanation
+Explanation
This RFC heavily relies on the functionalities of the Kademlia DHT already in use by Polkadot.
You can find a link to the specification here.
In a nutshell, on a specific node the current authority-discovery protocol publishes Kademila DHT records at startup and periodically. The records contain the full address of the node for each authorithy key it owns. The node tries also to find the full address of all authorities in the network by querying the DHT and picking up the first record it finds for each of the authority id it found on chain.
@@ -5811,24 +5745,24 @@ You can find a link to the specification Drawbacks
+Drawbacks
In theory the new protocol creates a bit more traffic on the DHT network, because it waits for DHT records to be received from more than one node, while in the current implementation we just take the first record that we receive and cancel all in-flight requests to other peers. However, because the redundancy factor will be relatively small and this operation happens rarerly, every 10min, this cost is negligible.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
This RFC's implementation https://github.com/paritytech/polkadot-sdk/pull/3786 had been tested on various local test networks and versi.
With regard to security the creation time is wrapped inside SignedAuthorityRecord wo it will be signed with the authority id key, so there is no way for other malicious nodes to manipulate this field without the received node observing.
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
Irrelevant.
-Performance
+Performance
Irrelevant.
-Ergonomics
+Ergonomics
Irrelevant.
-Compatibility
+Compatibility
The changes are backwards compatible with the existing protocol, so nodes with both the old protocol and newer protocol can exist in the network, this is achieved by the fact that we use protobuf for serializing and deserializing the records, so new fields will be ignore when deserializing with the older protocol and vice-versa when deserializing an old record with the new protocol the new field will be None and the new code accepts this record as being valid.
-Prior Art and References
+Prior Art and References
The enhancements have been inspired by the algorithm specified in here
-Unresolved Questions
+Unresolved Questions
N/A
-Future Directions and Related Material
+Future Directions and Related Material
N/A
Table of Contents
@@ -5874,23 +5808,23 @@ in order to speed up the time until all nodes have the newest record, nodes can
Authors Jonas Gehrlein & Alistair Stewart Summary
+Summary
This RFC proposes a flexible unbonding mechanism for tokens that are locked from staking on the Relay Chain (DOT/KSM), aiming to enhance user convenience without compromising system security.
Locking tokens for staking ensures that Polkadot is able to slash tokens backing misbehaving validators. With changing the locking period, we still need to make sure that Polkadot can slash enough tokens to deter misbehaviour. This means that not all tokens can be unbonded immediately, however we can still allow some tokens to be unbonded quickly.
The new mechanism leads to a signficantly reduced unbonding time on average, by queuing up new unbonding requests and scaling their unbonding duration relative to the size of the queue. New requests are executed with a minimum of 2 days, when the queue is comparatively empty, to the conventional 28 days, if the sum of requests (in terms of stake) exceed some threshold. In scenarios between these two bounds, the unbonding duration scales proportionately. The new mechanism will never be worse than the current fixed 28 days.
In this document we also present an empirical analysis by retrospectively fitting the proposed mechanism to the historic unbonding timeline and show that the average unbonding duration would drastically reduce, while still being sensitive to large unbonding events. Additionally, we discuss implications for UI, UX, and conviction voting.
Note: Our proposition solely focuses on the locks imposed from staking. Other locks, such as governance, remain unchanged. Also, this mechanism should not be confused with the already existing feature of FastUnstake, which lets users unstake tokens immediately that have not received rewards for 28 days or longer.
As an initial step to gauge its effectiveness and stability, it is recommended to implement and test this model on Kusama before considering its integration into Polkadot, with appropriate adjustments to the parameters. In the following, however, we limit our discussion to Polkadot.
-Motivation
+Motivation
Polkadot has one of the longest unbonding periods among all Proof-of-Stake protocols, because security is the most important goal. Staking on Polkadot is still attractive compared to other protocols because of its above-average staking APY. However the long unbonding period harms usability and deters potential participants that want to contribute to the security of the network.
The current length of the unbonding period imposes significant costs for any entity that even wants to perform basic tasks such as a reorganization / consolidation of their stashes, or updating their private key infrastructure. It also limits participation of users that have a large preference for liquidity.
The combination of long unbonding periods and high returns has lead to the proliferation of liquid staking, where parachains or centralised exchanges offer users their staked tokens before the 28 days unbonding period is over either in original DOT/KSM form or derivative tokens. Liquid staking is harmless if few tokens are involved but it could result in many validators being selected by a few entities if a large fraction of DOTs were involved. This may lead to centralization (see here for more discussion on threats of liquid staking) and an opportunity for attacks.
The new mechanism greatly increases the competitiveness of Polkadot, while maintaining sufficient security.
-Stakeholders
+Stakeholders
- Every DOT/KSM token holder
-Explanation
+Explanation
Before diving into the details of how to implement the unbonding queue, we give readers context about why Polkadot has a 28-day unbonding period in the first place. The reason for it is to prevent long-range attacks (LRA) that becomes theoretically possible if more than 1/3 of validators collude. In essence, a LRA describes the inability of users, who disconnect from the consensus at time t0 and reconnects later, to realize that validators which were legitimate at a certain time, say t0 but dropped out in the meantime, are not to be trusted anymore. That means, for example, a user syncing the state could be fooled by trusting validators that fell outside the active set of validators after t0, and are building a competitive and malicious chain (fork).
LRAs of longer than 28 days are mitigated by the use of trusted checkpoints, which are assumed to be no more than 28 days old. A new node that syncs Polkadot will start at the checkpoint and look for proofs of finality of later blocks, signed by 2/3 of the validators. In an LRA fork, some of the validator sets may be different but only if 2/3 of some validator set in the last 28 days signed something incorrect.
If we detect an LRA of no more than 28 days with the current unbonding period, then we should be able to detect misbehaviour from over 1/3 of validators whose nominators are still bonded. The stake backing these validators is considerable fraction of the total stake (empirically it is 0.287 or so). If we allowed more than this stake to unbond, without checking who it was backing, then the LRA attack might be free of cost for an attacker. The proposed mechansim allows up to half this stake to unbond within 28 days. This halves the amount of tokens that can be slashed, but this is still very high in absolute terms. For example, at the time of writing (19.06.2024) this would translate to around 120 millions DOTs.
@@ -5948,23 +5882,23 @@ The analysis can be reproduced or changed to other parameters using Potential Extension
In addition to a simple queue, we could add a market component that lets users always unbond from staking at the minimum possible waiting time)(== LOWER_BOUND, e.g., 2 days), by paying a variable fee. To achieve this, it is reasonable to split the total unbonding capacity into two chunks, with the first capacity for the simple queue and the remaining capacity for the fee-based unbonding. By doing so, we allow users to choose whether they want the quickest unbond and paying a dynamic fee or join the simple queue. Setting a capacity restriction for both queues enables us to guarantee a predictable unbonding time in the simple queue, while allowing users with the respective willingness to pay to get out even earlier. The fees are dynamically adjusted and are proportional to the unbonding stake (and thereby expressed in a percentage of the requested unbonding stake). In contrast to a unified queue, this prevents the issue that users paying a fee jump in front of other users not paying a fee, pushing their unbonding time back (which would be bad for UX). The revenue generated could be burned.
This extension and further specifications are left out of this RFC, because it adds further complexity and the empirical analysis above suggests that average unbonding times will already be close the LOWER_BOUND, making a more complex design unnecessary. We advise to first implement the discussed mechanism and assess after some experience whether an extension is desirable.
-Drawbacks
+Drawbacks
- Lower security for LRAs: Without a doubt, the theoretical security against LRAs decreases. But, as we argue, the attack is still costly enough to deter attacks and the attack is sufficiently theoretical. Here, the benefits outweigh the costs.
- Griefing attacks: A large holder could pretend to unbond a large amount of their tokens to prevent other users to exit the network earlier. This would, however be costly due to the fact that the holder loses out on staking rewards. The larger the impact on the queue, the higher the costs. In any case it must be noted that the
UPPER_BOUND is still 28 days, which means that nominators are never left with a longer unbonding period than currently. There is not enough gain for the attacker to endure this cost.
- Challenge for Custodians and Liquid Staking Providers: Changing the unbonding time, especially making it flexible, requires entities that offer staking derivatives to rethink and rework their products.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
NA
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
NA
-Performance
+Performance
The authors cannot see any potential impact on performance.
-Ergonomics
+Ergonomics
The authors cannot see any potential impact on ergonomics for developers. We discussed potential impact on UX/UI for users above.
-Compatibility
+Compatibility
The authors cannot see any potential impact on compatibility. This should be assessed by the technical fellows.
-Prior Art and References
+Prior Art and References
- Ethereum proposed a similar solution
- Alistair did some initial write-up
@@ -6001,20 +5935,20 @@ The analysis can be reproduced or changed to other parameters using Summary
+Summary
This RFC proposes a change to the extrinsic format to include a transaction extension version.
-Motivation
+Motivation
The extrinsic format supports to be extended with transaction extensions. These transaction extensions are runtime specific and can be different per chain. Each transaction extension can add data to the extrinsic itself or extend the signed payload.
This means that adding a transaction extension is breaking the chain specific extrinsic format. A recent example was the introduction of the CheckMetadatHash to Polkadot and all its system chains.
As the extension was adding one byte to the extrinsic, it broke a lot of tooling. By introducing an extra version for the transaction extensions it will be possible to introduce changes to these transaction extensions while still being backwards compatible.
Based on the version of the transaction extensions, each chain runtime could decode the extrinsic correctly and also create the correct signed payload.
-Stakeholders
+Stakeholders
- Runtime users
- Runtime devs
- Wallet devs
-Explanation
+Explanation
RFC84 introduced the extrinsic format 5. The idea is to piggyback onto this change of the extrinsic format to add the extra version for the transaction extensions. If required, this could also come
as extrinsic format 6, but 5 is not yet deployed anywhere.
The extrinsic format supports the following types of transactions:
@@ -6030,25 +5964,25 @@ as extrinsic format 6, but 5 is not yet deployed anywh
The Version being a SCALE encoded u8 representing the version of the transaction extensions.
In the chain runtime the version can be used to determine which set of transaction extensions should be used to decode and to validate the transaction.
-Drawbacks
+Drawbacks
This adds one byte more to each signed transaction.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
There is no impact on testing, security or privacy.
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
This will ensure that changes to the transactions extensions can be done in a backwards compatible way.
-Performance
+Performance
There is no performance impact.
-Ergonomics
+Ergonomics
Runtime developers need to take care of the versioning and ensure to bump as required, so that there are no compatibility breaking changes without a bump of the version. It will also add a little bit more code in the runtime
to decode these old versions, but this should be neglectable.
-Compatibility
+Compatibility
When introduced together with extrinsic format version 5 from RFC84, it can be implemented in a backwards compatible way. So, transactions can still be send using the
old extrinsic format and decoded by the runtime.
-Prior Art and References
+Prior Art and References
None.
-Unresolved Questions
+Unresolved Questions
None.
-Future Directions and Related Material
+Future Directions and Related Material
None.
Table of Contents
@@ -6085,14 +6019,14 @@ old extrinsic format and decoded by the runtime.
Authors Adrian Catangiu Summary
+Summary
This RFC proposes a new instruction that provides a way to initiate on remote chains, asset transfers which
transfer multiple types (teleports, local-reserve, destination-reserve) of assets, using XCM alone.
The currently existing instructions are too opinionated and force each XCM asset transfer to a single
transfer type (teleport, local-reserve, destination-reserve). This results in inability to combine different
types of transfers in single transfer which results in overall poor UX when trying to move assets across
chains.
-Motivation
+Motivation
XCM is the de-facto cross-chain messaging protocol within the Polkadot ecosystem, and cross-chain
assets transfers is one of its main use-cases. Unfortunately, in its current spec, it does not support
initiating on a remote chain, one or more transfers that combine assets with different transfer types.
@@ -6114,14 +6048,14 @@ For example, allows single XCM program execution to transfer multiple assets fro
Kusama Asset Hub, over the bridge through Polkadot Asset Hub with final destination ParaP on Polkadot.
With current XCM, we are limited to doing multiple independent transfers for each individual hop in order to
move both "interesting" assets, but also "supporting" assets (used to pay fees).
-Stakeholders
+Stakeholders
- Runtime users
- Runtime devs
- Wallet devs
- dApps devs
-Explanation
+Explanation
A new instruction InitiateAssetsTransfer is introduced that initiates an assets transfer from the
chain it is executed on, to another chain. The executed transfer is point-to-point (chain-to-chain)
with all of the transfer properties specified in the instruction parameters. The instruction also
@@ -6309,9 +6243,9 @@ by executing a single XCM message, even though we'll be mixing multiple
).unwrap();
})
}
-Drawbacks
+Drawbacks
No drawbacks identified.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
There should be no security risks related to the new instruction from the XCVM perspective. It follows the same
pattern as with single-type asset transfers, only now it allows combining multiple types at once.
Improves security by enabling
@@ -6320,16 +6254,16 @@ which minimizes the potential free/unpaid work that a receiving chain has to do.
required execution fee payment, part of the instruction logic through the remote_fees: Option<AssetTransferFilter>
parameter, which will make sure the remote XCM starts with a single-asset-holding-loading-instruction,
immediately followed by a BuyExecution using said asset.
-Performance, Ergonomics, and Compatibility
+Performance, Ergonomics, and Compatibility
This brings no impact to the rest of the XCM spec. It is a new, independent instruction, no changes to existing instructions.
Enhances the exposed functionality of Polkadot. Will allow multi-chain transfers that are currently forced to happen in
multiple programs per asset per "hop", to be possible in a single XCM program.
-Performance
+Performance
No performance changes/implications.
-Ergonomics
+Ergonomics
The proposal enhances developers' and users' cross-chain asset transfer capabilities. This enhancement is optimized for XCM
programs transferring multiple assets, needing to run their logic across multiple chains.
-Compatibility
+Compatibility
Does this proposal break compatibility with existing interfaces, older versions of implementations? Summarize necessary
migrations or upgrade strategies, if any.
This enhancement is compatible with all existing XCM programs and versions.
@@ -6338,11 +6272,11 @@ success.
A program where the new instruction is used to initiate multiple types of asset transfers, cannot be downgraded to older
XCM versions, because there is no equivalent capability there.
Such conversion attempts will explicitly fail.
-Prior Art and References
+Prior Art and References
None.
-Unresolved Questions
+Unresolved Questions
None.
-Future Directions and Related Material
+Future Directions and Related Material
None.
Table of Contents
@@ -6375,10 +6309,10 @@ Such conversion attempts will explicitly fail.
Authors Adrian Catangiu Summary
+Summary
The Transact XCM instruction currently forces the user to set a specific maximum weight allowed to the inner call and then also pay for that much weight regardless of how much the call actually needs in practice.
This RFC proposes improving the usability of Transact by removing that parameter and instead get and charge the actual weight of the inner call from its dispatch info on the remote chain.
-Motivation
+Motivation
The UX of using Transact is poor because of having to guess/estimate the require_weight_at_most weight used by the inner call on the target.
We've seen multiple Transact on-chain failures caused by guessing wrong values for this require_weight_at_most even though the rest of the XCM program would have worked.
In practice, this parameter only adds UX overhead with no real practical value. Use cases fall in one of two categories:
@@ -6391,40 +6325,40 @@ weight limit parameter.
We've had multiple OpenGov root/whitelisted_caller proposals initiated by core-devs completely or partially fail
because of incorrect configuration of require_weight_at_most parameter. This is a strong indication that the
instruction is hard to use.
-Stakeholders
+Stakeholders
- Runtime Users,
- Runtime Devs,
- Wallets,
- dApps,
-Explanation
+Explanation
The proposed enhancement is simple: remove require_weight_at_most parameter from the instruction:
- Transact { origin_kind: OriginKind, require_weight_at_most: Weight, call: DoubleEncoded<Call> },
+ Transact { origin_kind: OriginKind, call: DoubleEncoded<Call> },
The XCVM implementation shall no longer use require_weight_at_most for weighing. Instead, it shall weigh the Transact instruction by decoding and weighing the inner call.
-Drawbacks
+Drawbacks
No drawbacks, existing scenarios work as before, while this also allows new/easier flows.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
Currently, an XCVM implementation can weigh a message just by looking at the decoded instructions without decoding the Transact's call, but assuming require_weight_at_most weight for it. With the new version it has to decode the inner call to know its actual weight.
But this does not actually change the security considerations, as can be seen below.
With the new Transact the weighing happens after decoding the inner call. The entirety of the XCM program containing this Transact needs to be either covered by enough bought weight using a BuyExecution, or the origin has to be allowed to do free execution.
The security considerations around how much can someone execute for free are the same for
both this new version and the old. In both cases, an "attacker" can do the XCM decoding (including Transact inner calls) for free by adding a large enough BuyExecution without actually having the funds available.
In both cases, decoding is done for free, but in both cases execution fails early on BuyExecution.
-Performance, Ergonomics, and Compatibility
-Performance
+Performance, Ergonomics, and Compatibility
+Performance
No performance change.
-Ergonomics
+Ergonomics
Ergonomics are slightly improved by simplifying Transact API.
-Compatibility
+Compatibility
Compatible with previous XCM programs.
-Prior Art and References
+Prior Art and References
None.
-Unresolved Questions
+Unresolved Questions
None.
-Future Directions and Related Material
+Future Directions and Related Material
None.
Table of Contents
@@ -6468,13 +6402,13 @@ both this new version and the old. In both cases, an "attacker" can do
Authors Andrei Sandu Summary
+Summary
Elastic scaling is not resilient against griefing attacks without a way for a PoV (Proof of Validity)
to commit to the particular core index it was intended for. This RFC proposes a way to include
core index information in the candidate commitments and the CandidateDescriptor data structure
in a backward compatible way. Additionally, it proposes the addition of a SessionIndex field in
the CandidateDescriptor to make dispute resolution more secure and robust.
-Motivation
+Motivation
This RFC proposes a way to solve two different problems:
- For Elastic Scaling, it prevents anyone who has acquired a valid collation to DoS the parachain
@@ -6489,14 +6423,14 @@ dispute. The dispute may concern a relay chain block not yet imported by a
validator. In this case, validators can safely assume the session index refers to the session
the candidate has appeared in, otherwise, the chain would have rejected the candidate.
-Stakeholders
+Stakeholders
- Polkadot core developers.
- Cumulus node developers.
- Tooling, block explorer developers.
This approach and alternatives have been considered and discussed in this issue.
-Explanation
+Explanation
The approach proposed below was chosen primarily because it minimizes the number of breaking
changes, the complexity and takes less implementation and testing time. The proposal is to change
the existing primitives while keeping binary compatibility with the older versions. We repurpose
@@ -6642,28 +6576,28 @@ A candidate must not be backed if any of the following are true:
as backers did off-chain. It currently stores the claim queue at the newest allowed
relay parent corresponding to the claim queue offset 0. The runtime needs to be changed to store
a claim queue snapshot at all allowed relay parents.
-Drawbacks
+Drawbacks
The only drawback is that further additions to the descriptor are limited to the amount of
remaining unused space.
-Testing, Security, and Privacy
+Testing, Security, and Privacy
Standard testing (unit tests, CI zombienet tests) for functionality and mandatory security audit
to ensure the implementation does not introduce any new security issues.
Backward compatibility of the implementation will be tested on testnets (Versi and Westend).
There is no impact on privacy.
-Performance
+Performance
Overall performance will be improved by not checking the collator signatures in runtime and nodes.
The impact on the UMP queue and candidate receipt processing is negligible.
The ClaimQueueOffset along with the relay parent choice allows parachains to optimize their
block production for either throughput or lower XCM message processing latency. A value of 0
with the newest relay parent provides the best latency while picking older relay parents avoids
re-orgs.
-Ergonomics
+Ergonomics
It is mandatory for elastic parachains to switch to the new receipt format and commit to a
core by sending the UMPSignal::SelectCore message. It is optional but desired that all
parachains switch to the new receipts for providing the session index for disputes.
The implementation of this RFC itself must not introduce any breaking changes for the parachain
runtime or collator nodes.
-Compatibility
+Compatibility
The proposed changes are not fully backward compatible, because older validators verify the
collator signature of candidate descriptors.
Additional care must be taken before enabling the new descriptors by waiting for at least
@@ -6688,12 +6622,12 @@ present in the receipt.
Any tooling that decodes UMP XCM messages needs an update to support or ignore the new UMP
messages, but they should be fine to decode the regular XCM messages that come before the
separator.
-Prior Art and References
+Prior Art and References
Forum discussion about a new CandidateReceipt format:
https://forum.polkadot.network/t/pre-rfc-discussion-candidate-receipt-format-v2/3738
-Unresolved Questions
+Unresolved Questions
N/A
-Future Directions and Related Material
+Future Directions and Related Material
The implementation is extensible and future-proof to some extent. With minimal or no breaking
changes, additional fields can be added in the candidate descriptor until the reserved space is
exhausted
@@ -6735,7 +6669,7 @@ by using the version field of the descriptor introduced in this RFC
Authors Francisco Aguirre Summary
+Summary
XCM already handles execution fees in an effective and efficient manner using the BuyExecution instruction.
However, other types of fees are not handled as effectively -- for example, delivery fees.
Fees exist that can't be measured using Weight -- as execution fees can -- so a new method should be thought up for those cases.
@@ -6744,7 +6678,7 @@ This RFC proposes making the fee handling system simpler and more general, by do
Adding a fees register
Deprecating BuyExecution and adding a new instruction PayFees with new semantics to ultimately replace it.
-Motivation
+Motivation
Execution fees are handled correctly by XCM right now.
However, the addition of extra fees, like for message delivery, result in awkward ways of integrating them into the XCVM implementation.
This is because these types of fees are not included in the language.
@@ -6752,14 +6686,14 @@ The standard should have a way to correctly deal with these implementation speci
The new instruction moves the specified amount of fees from the holding register to a dedicated fees register that the XCVM can use in flexible ways depending on its implementation.
The XCVM implementation is free to use these fees to pay for execution fees, transport fees, or any other type of fee that might be necessary.
This moves the specifics of fees further away from the XCM standard, and more into the actual underlying XCVM implementation, which is a good thing.
-Stakeholders
+Stakeholders
- Runtime Users
- Runtime Devs
- Wallets
- dApps
-Explanation
+Explanation
The new instruction that will replace BuyExecution is a much simpler and general version: PayFees.
This instruction takes one Asset, takes it from the holding register, and puts it into a new fees register.
The XCVM implementation can now use this Asset to make sure every necessary fee is paid for, this includes execution fees, delivery fees, and any other type of fee
@@ -6790,27 +6724,27 @@ BuyExecution { asset, weight_limit }
PayFees { asset }
// ...rest
}
-There needs to be an explicit change from BuyExecution to PayFees, most often accompanied by a reduction in the assets passed in.
It might become a security concern if leftover fees are trapped, since a lot of them are expected.
-There should be no performance downsides to this approach.
The fees register is a simplification that may actually result in better performance, in the case an implementation is doing a workaround to achieve what this RFC proposes.
The interface is going to be very similar to the already existing one.
Even simpler since PayFees will only receive one asset.
That asset will allow users to limit the amount of fees they are willing to pay.
This RFC can't just change the semantics of the BuyExecution instruction since that instruction accepts any funds, uses what it needs and returns the rest immediately.
The new proposed instruction, PayFees, doesn't return the leftover immediately, it keeps it in the fees register.
In practice, the deprecated BuyExecution needs to be slowly rolled out in favour of PayFees.
The closed RFC PR on the xcm-format repository, before XCM RFCs got moved to fellowship RFCs: https://github.com/polkadot-fellows/xcm-format/pull/53.
-None
-This proposal would greatly benefit from an improved asset trapping system.
CustomAssetClaimer is also related, as it directly improves the ergonomics of this proposal.
LeftoverAssetsDestination execution hint would also similarly improve the ergonomics.
@@ -6846,12 +6780,12 @@ In practice, the deprecatedBuyExecution needs to be slowly rolled
A previous XCM RFC (https://github.com/polkadot-fellows/xcm-format/pull/37) introduced a SetAssetClaimer instruction.
This idea of instructing the XCVM to change some implementation-specific behavior is useful.
In order to generalize this mechanism, this RFC introduces a new instruction SetHints
and makes the SetAssetClaimer be just one of many possible execution hints.
There is a need for specifying how certain implementation-specific things should behave. Things like who can claim the assets or what can be done instead of trapping assets. Another idea for a hint:
@@ -6859,13 +6793,13 @@ Another idea for a hint:AssetForFees: to signify to the executor what asset the user prefers to use for fees.LeftoverAssetsDestination: for depositing leftover assets to a destination instead of trapping themA new instruction, SetHints, will be added.
This instruction will take a single parameter of type Hint, an enumeration.
The first variant for this enum is AssetClaimer, which allows to specify a location that should be able to claim trapped assets.
@@ -6886,27 +6820,27 @@ enum Hint {
type NumVariants = /* Number of variants of the `Hint` enum */;
}
-
The SetHints instruction might be hard to benchmark, since we should look into the actual hints being set to know how much weight to attribute to it.
Hints are specified on a per-message basis, so they have to be specified at the beginning of a message.
If they were to be specified at the end, hints like AssetClaimer would be useless if an error occurs beforehand and assets get trapped before ever reaching the hint.
The instruction takes a bounded vector of hints so as to not force barriers to allow an arbitrary number of SetHint instructions.
None.
-The SetHints instruction provides a better integration with barriers.
If we had to add one barrier for SetAssetClaimer and another for each new hint that's added, barriers would need to be changed all the time.
Also, this instruction would make it simpler to write XCM programs.
You only need to specify the hints you want in one single instruction at the top of your program.
None.
-The previous RFC PR in the xcm-format repository before XCM RFCs moved to fellowship RFCs: https://github.com/polkadot-fellows/xcm-format/pull/59.
-None.
-None.
Table of Contents
@@ -6939,36 +6873,36 @@ You only need to specify the hints you want in one single instruction at the topThis RFC aims to remove the NetworkIds of Westend and Rococo, arguing that testnets shouldn't go in the language.
We've already seen the plans to phase out Rococo and Paseo has appeared.
Instead of constantly changing the testnets included in the language, we should favor specifying them via their genesis hash,
using NetworkId::ByGenesis.
Remove Westend and Rococo from the included NetworkIds in the language.
This RFC will make it less convenient to specify a testnet, but not by a large amount.
-None.
-None.
-It will very slightly reduce the ergonomics of testnet developers but improve the stability of the language.
-NetworkId::Rococo and NetworkId::Westend can just use NetworkId::ByGenesis, as can other testnets.
A previous attempt to add NetworkId::Paseo: https://github.com/polkadot-fellows/xcm-format/pull/58.
None.
-None.
Table of Contents
@@ -7007,11 +6941,11 @@ usingNetworkId::ByGenesis.
XCM programs generated by the InitiateAssetTransfer instruction shall have the option to carry over the original origin all the way to the final destination. They shall do so by internally making use of AliasOrigin or ClearOrigin depending on given parameters.
This allows asset transfers to retain their original origin even across multiple hops.
Ecosystem chains would have to change their trusted aliasing rules to effectively make use of this feature.
-Currently, all XCM asset transfer instructions ultimately clear the origin in the remote XCM message by use of the ClearOrigin instruction. This is done for security considerations to ensure that subsequent (user-controlled) instructions cannot command the authority of the sending chain.
The problem with this approach is that it limits what can be achieved on remote chains through XCM. Most XCM operations require having an origin, and following any asset transfer the origin is lost, meaning not much can be done other than depositing the transferred assets to some local account or transferring them onward to another chain.
For example, we cannot transfer some funds for buying execution, then do a Transact (all in the same XCM message).
NetworkId::ByGenesis.
Transact XCM programs today require a two step process:
And we want to be able to do it using a single XCM program.
-Runtime Users, Runtime Devs, wallets, cross-chain dApps.
-In the case of XCM programs going from source-chain directly to dest-chain without an intermediary hop, we can enable scenarios such as above by using the AliasOrigin instruction instead of the ClearOrigin instruction.
Instead of clearing the source-chain origin, the destination chain shall attempt to alias source-chain to "original origin" on the source chain.
Most common such origin aliasing would be X1(Parachain(source-chain)) -> X2(Parachain(source-chain), AccountId32(origin-account)) for the case of a single hop transfer where the initiator is a (signed/pure/proxy) account origin-account on source-chain.
@@ -7071,35 +7005,101 @@ involved chains.
-In terms of ergonomics and user experience, this support for combining an asset transfer with a subsequent action (like Transact) is a net positive.
In terms of performance, and privacy, this is neutral with no changes.
In terms of security, the feature by itself is also neutral because it allows preserve_origin: false usage for operating with no extra trust assumptions. When wanting to support preserving origin, chains need to configure secure origin aliasing filters. The one suggested in this RFC should be the right choice for the majority of chains, but each chain will ultimately choose depending on their business model and logic (e.g. chain does not plan to integrate with Asset Hub). It is up to the individual chains to configure accordingly.
Barriers should now allow AliasOrigin, DescendOrigin or ClearOrigin.
Normally, XCM program builders should audit their programs and eliminate assumptions of "no origin" on remote side of this instruction. In this case, the InitiateAssetsTransfer has not been released yet, it will be part of XCMv5, and we can make this change part of the same XCMv5 so that there isn't even the possibility of someone in the wild having built XCM programs using this instruction on those wrong assumptions.
The working assumption going forward is that the origin on the remote side can either be cleared or it can be the local origin's reanchored location. This assumption is in line with the current behavior of remote XCM programs sent over using pallet_xcm::send.
The existing DepositReserveAsset, InitiateReserveWithdraw and InitiateTeleport cross chain asset transfer instructions will not attempt to do origin aliasing and will always clear origin same as before for compatibility reasons.
No impact.
-Improves ergonomics by allowing the local origin to operate on the remote chain even when the XCM program includes an asset transfer.
-At the executor-level this change is backwards and forwards compatible. Both types of programs can be executed on new and old versions of XCM with no changes in behavior.
New version of the InitiateAssetsTransfer instruction acts same as before when used with preserve_origin: false.
For using the new capabilities, the XCM builder has to verify that the involved chains have the required origin-aliasing filters configured and use some new version of Barriers aware of AliasOrigin as an allowed alternative to ClearOrigin.
For compatibility reasons, this RFC proposes this mechanism be added as an enhancement to the yet unreleased InitiateAssetsTransfer instruction, thus eliminating possibilities of XCM logic breakages in the wild.
Following the same logic, the existing DepositReserveAsset, InitiateReserveWithdraw and InitiateTeleport cross chain asset transfer instructions will not attempt to do origin aliasing and will always clear the origin same as before for compatibility reasons.
Any one of DepositReserveAsset, InitiateReserveWithdraw and InitiateTeleport instructions can be replaced with a InitiateAssetsTransfer instruction with or without origin aliasing, thus providing a clean and clear upgrade path for opting-in this new feature.
None
+Table of Contents
+ +:pending_code as intermediate storage key for the runtime code| Start Date | 14.10.2024 |
|---|---|
| Description | Store a runtime upgrade in :pending_code before moving it to :code. |
| Authors | Bastian Köcher |
The code of a runtime is stored in its own state, and when performing a runtime upgrade, this code is replaced. The new runtime can contain runtime migrations that adapt the state to the state layout as defined by the runtime code. This runtime migration is executed when building the first block with the new runtime code. Anything that interacts with the runtime state uses the state layout as defined by the runtime code. So, when trying to load something from the state in the block that applied the runtime upgrade, it will use the new state layout but will decode the data from the non-migrated state. In the worst case, the data is incorrectly decoded, which may lead to crashes or halting of the chain.
+This RFC proposes to store the new runtime code under a different storage key when applying a runtime upgrade. This way, all the off-chain logic can still load the old runtime code under the default storage key and decode the state correctly. The block producer is then required to use this new runtime code to build the next block. While building the next block, the runtime is executing the migrations and moves the new runtime code to the default runtime code location. So, the runtime code found under the default location is always the correct one to decode the state from which the runtime code was loaded.
+While the issue of having undecodable state only exists for the one block in which the runtime upgrade was applied, it still impacts anything that reads state data, like block explorers, UIs, nodes, etc. For block explorers, the issue mainly results in indexing invalid data and UIs may show invalid data to the user. For nodes, reading incorrect data may lead to a performance degradation of the network. There are also ways to prevent certain decoding issues from happening, but it requires that developers are aware of this issue and also requires introducing extra code, which could introduce further bugs down the line.
+So, this RFC tries to solve these issues by fixing the underlying problem of having temporary undecodable state.
+The runtime code is stored under the special key :code in the state. Nodes and other tooling read the runtime code under this storage key when they want to interact with the runtime for e.g., building/importing blocks or getting the metadata to read the state. To update the runtime code the runtime overwrites the value at :code, and then from the next block on, the new runtime will be loaded.
+This RFC proposes to first store the new runtime code under :pending_code in the state for one block. When the next block is being built, the block builder first needs to check if :pending_code is set, and if so, it needs to load the runtime from this storage key. While building the block the runtime will move :pending_code to :code to have the runtime code at the default location. Nodes importing the block will also need to load :pending_code if it exists to ensure that the correct runtime code is used. By doing it this way, the runtime code found at :code in the state of a block will always be able to decode the state.
+Furthermore, this RFC proposes to introduce system_version: 3. The system_version was introduced in RFC42. Version 3 would then enable the usage of :pending_code when applying a runtime code upgrade. This way, the feature can be introduced first and enabled later when the majority of the nodes have upgraded.
Because the first block built with the new runtime code will move the runtime code from :pending_code to :code, the runtime code will need to be loaded. This means the runtime code will appear in the proof of validity of a parachain for the first block built with the new runtime code. Generally this is not a problem as the runtime code is also loaded by the parachain when setting the new runtime code.
+There is still the possibility of having state that is not migrated even when following the proposal as presented by this RFC. The issue is that if the amount of data to be migrated is too big, not all of it can be migrated in one block, because either it takes more time than there is assigned for a block or parachains for example have a fixed budget for their proof of validity. To solve this issue there already exist multi-block migrations that can chunk the migration across multiple blocks. Consensus-critical data needs to be migrated in the first block to ensure that block production etc., can continue. For the other data being migrated by multi-block migrations the migrations could for example expose to the outside which keys are being migrated and should not be indexed until the migration is finished.
Testing should be straightforward and most of the existing testing should already be good enough. Extending with some checks that :pending_code is moved to :code.
The performance should not be impacted besides requiring loading the runtime code in the first block being built with the new runtime code.
+It only alters the way blocks are produced and imported after applying a runtime upgrade. This means that only nodes need to be adapted to the changes of this RFC.
+The change will require that the nodes are upgraded before the runtime starts using this feature. Otherwise they will fail to import the block build by :pending_code.
+For Polkadot/Kusama this means that also the parachain nodes need to be running with a relay chain node version that supports this new feature. Otherwise the parachains will stop producing/finalizing nodes as they can not sync the relay chain any more.
The issue initially reported a bug that led to this RFC. It also discusses multiple solutions for the problem.
None
move function. When using the V1 trie layout every value bigger than 32 bytes is put into the db separately. This means a low level move function would only need to move the hash of the runtime code from :code to :pending_code.Table of Contents