helps https://github.com/paritytech/polkadot-sdk/issues/439. closes https://github.com/paritytech/polkadot-sdk/issues/473. PR link in the older substrate repository: https://github.com/paritytech/substrate/pull/13498. # Context Rewards payout is processed today in a single block and limited to `MaxNominatorRewardedPerValidator`. This number is currently 512 on both Kusama and Polkadot. This PR tries to scale the nominators payout to an unlimited count in a multi-block fashion. Exposures are stored in pages, with each page capped to a certain number (`MaxExposurePageSize`). Starting out, this number would be the same as `MaxNominatorRewardedPerValidator`, but eventually, this number can be lowered through new runtime upgrades to limit the rewardeable nominators per dispatched call instruction. The changes in the PR are backward compatible. ## How payouts would work like after this change Staking exposes two calls, 1) the existing `payout_stakers` and 2) `payout_stakers_by_page`. ### payout_stakers This remains backward compatible with no signature change. If for a given era a validator has multiple pages, they can call `payout_stakers` multiple times. The pages are executed in an ascending sequence and the runtime takes care of preventing double claims. ### payout_stakers_by_page Very similar to `payout_stakers` but also accepts an extra param `page_index`. An account can choose to payout rewards only for an explicitly passed `page_index`. **Lets look at an example scenario** Given an active validator on Kusama had 1100 nominators, `MaxExposurePageSize` set to 512 for Era e. In order to pay out rewards to all nominators, the caller would need to call `payout_stakers` 3 times. - `payout_stakers(origin, stash, e)` => will pay the first 512 nominators. - `payout_stakers(origin, stash, e)` => will pay the second set of 512 nominators. - `payout_stakers(origin, stash, e)` => will pay the last set of 76 nominators. ... - `payout_stakers(origin, stash, e)` => calling it the 4th time would return an error `InvalidPage`. The above calls can also be replaced by `payout_stakers_by_page` and passing a `page_index` explicitly. ## Commission note Validator commission is paid out in chunks across all the pages where each commission chunk is proportional to the total stake of the current page. This implies higher the total stake of a page, higher will be the commission. If all the pages of a validator's single era are paid out, the sum of commission paid to the validator across all pages should be equal to what the commission would have been if we had a non-paged exposure. ### Migration Note Strictly speaking, we did not need to bump our storage version since there is no migration of storage in this PR. But it is still useful to mark a storage upgrade for the following reasons: - New storage items are introduced in this PR while some older storage items are deprecated. - For the next `HistoryDepth` eras, the exposure would be incrementally migrated to its corresponding paged storage item. - Runtimes using staking pallet would strictly need to wait at least `HistoryDepth` eras with current upgraded version (14) for the migration to complete. At some era `E` such that `E > era_at_which_V14_gets_into_effect + HistoryDepth`, we will upgrade to version X which will remove the deprecated storage items. In other words, it is a strict requirement that E<sub>x</sub> - E<sub>14</sub> > `HistoryDepth`, where E<sub>x</sub> = Era at which deprecated storages are removed from runtime, E<sub>14</sub> = Era at which runtime is upgraded to version 14. - For Polkadot and Kusama, there is a [tracker ticket](https://github.com/paritytech/polkadot-sdk/issues/433) to clean up the deprecated storage items. ### Storage Changes #### Added - ErasStakersOverview - ClaimedRewards - ErasStakersPaged #### Deprecated The following can be cleaned up after 84 eras which is tracked [here](https://github.com/paritytech/polkadot-sdk/issues/433). - ErasStakers. - ErasStakersClipped. - StakingLedger.claimed_rewards, renamed to StakingLedger.legacy_claimed_rewards. ### Config Changes - Renamed MaxNominatorRewardedPerValidator to MaxExposurePageSize. ### TODO - [x] Tracker ticket for cleaning up the old code after 84 eras. - [x] Add companion. - [x] Redo benchmarks before merge. - [x] Add Changelog for pallet_staking. - [x] Pallet should be configurable to enable/disable paged rewards. - [x] Commission payouts are distributed across pages. - [x] Review documentation thoroughly. - [x] Rename `MaxNominatorRewardedPerValidator` -> `MaxExposurePageSize`. - [x] NMap for `ErasStakersPaged`. - [x] Deprecate ErasStakers. - [x] Integrity tests. ### Followup issues [Runtime api for deprecated ErasStakers storage item](https://github.com/paritytech/polkadot-sdk/issues/426) --------- Co-authored-by: Javier Viola <javier@parity.io> Co-authored-by: Ross Bulat <ross@parity.io> Co-authored-by: command-bot <>
Polkadot
Implementation of a https://polkadot.network node in Rust based on the Substrate framework.
The README provides information about installing the polkadot binary and developing on the codebase. For more specific
guides, like how to run a validator node, see the Polkadot Wiki.
Installation
Using a pre-compiled binary
If you just wish to run a Polkadot node without compiling it yourself, you may either run the latest binary from our releases page, or install Polkadot from one of our package repositories.
Debian-based (Debian, Ubuntu)
Currently supports Debian 10 (Buster) and Ubuntu 20.04 (Focal), and derivatives. Run the following
commands as the root user.
# Import the security@parity.io GPG key
gpg --recv-keys --keyserver hkps://keys.mailvelope.com 9D4B2B6EB8F97156D19669A9FF0812D491B96798
gpg --export 9D4B2B6EB8F97156D19669A9FF0812D491B96798 > /usr/share/keyrings/parity.gpg
# Add the Parity repository and update the package index
echo 'deb [signed-by=/usr/share/keyrings/parity.gpg] https://releases.parity.io/deb release main' > /etc/apt/sources.list.d/parity.list
apt update
# Install the `parity-keyring` package - This will ensure the GPG key
# used by APT remains up-to-date
apt install parity-keyring
# Install polkadot
apt install polkadot
Installation from the Debian repository will create a systemd service that can be used to run a
Polkadot node. This is disabled by default, and can be started by running systemctl start polkadot
on demand (use systemctl enable polkadot to make it auto-start after reboot). By default, it will
run as the polkadot user. Command-line flags passed to the binary can be customized by editing
/etc/default/polkadot. This file will not be overwritten on updating Polkadot. You may also just
run the node directly from the command-line.
Building
Since the Polkadot node is based on Substrate, first set up your build environment according to the Substrate installation instructions.
Install via Cargo
Make sure you have the support software installed from the Build from Source section below this section.
If you want to install Polkadot in your PATH, you can do so with:
cargo install --git https://github.com/paritytech/polkadot-sdk --tag <version> polkadot --locked
Build from Source
Build the client by cloning this repository and running the following commands from the root directory of the repo:
git checkout <latest tagged release>
./scripts/init.sh
cargo build --release
Note: if you want to move the built polkadot binary somewhere (e.g. into $PATH) you will also
need to move polkadot-execute-worker and polkadot-prepare-worker. You can let cargo do all this
for you by running:
cargo install --path . --locked
Build from Source with Docker
You can also build from source using Parity CI docker image:
git checkout <latest tagged release>
docker run --rm -it -w /shellhere/polkadot \
-v $(pwd):/shellhere/polkadot \
paritytech/ci-linux:production cargo build --release
sudo chown -R $(id -u):$(id -g) target/
If you want to reproduce other steps of CI process you can use the following guide.
Networks
This repo supports runtimes for Polkadot, Kusama, and Westend.
Connect to Polkadot Mainnet
Connect to the global Polkadot Mainnet network by running:
../target/release/polkadot --chain=polkadot
You can see your node on [telemetry] (set a custom name with --name "my custom name").
telemetry: https://telemetry.polkadot.io/#list/Polkadot
Connect to the "Kusama" Canary Network
Connect to the global Kusama canary network by running:
../target/release/polkadot --chain=kusama
You can see your node on [telemetry] (set a custom name with --name "my custom name").
telemetry: https://telemetry.polkadot.io/#list/Kusama
Connect to the Westend Testnet
Connect to the global Westend testnet by running:
../target/release/polkadot --chain=westend
You can see your node on [telemetry] (set a custom name with --name "my custom name").
telemetry: https://telemetry.polkadot.io/#list/Westend
Obtaining DOTs
If you want to do anything on Polkadot, Kusama, or Westend, then you'll need to get an account and some DOT, KSM, or WND tokens, respectively. Follow the instructions on the Wiki to obtain tokens for your testnet of choice.
Hacking on Polkadot
If you'd actually like to hack on Polkadot, you can grab the source code and build it. Ensure you have Rust and the support software installed.
Then, grab the Polkadot source code:
git clone https://github.com/paritytech/polkadot-sdk.git
cd polkadot
Then build the code. You will need to build in release mode (--release) to start a network. Only
use debug mode for development (faster compile times for development and testing).
cargo build
You can run the tests if you like:
cargo test --workspace --profile testnet
# Or run only the tests for specified crated
cargo test -p <crate-name> --profile testnet
You can start a development chain with:
cargo run --bin polkadot -- --dev
Detailed logs may be shown by running the node with the following environment variables set:
RUST_LOG=debug RUST_BACKTRACE=1 cargo run --bin polkadot -- --dev
Development
You can run a simple single-node development "network" on your machine by running:
cargo run --bin polkadot --release -- --dev
You can muck around by heading to https://polkadot.js.org/apps and choose "Local Node" from the Settings menu.
Local Two-node Testnet
If you want to see the multi-node consensus algorithm in action locally, then you can create a local testnet. You'll need two terminals open. In one, run:
polkadot --dev --alice -d /tmp/alice
And in the other, run:
polkadot --dev --bob -d /tmp/bob --bootnodes '/ip4/127.0.0.1/tcp/30333/p2p/ALICE_BOOTNODE_ID_HERE'
Ensure you replace ALICE_BOOTNODE_ID_HERE with the node ID from the output of the first terminal.
Monitoring
Once you set this up you can take a look at the Polkadot Grafana dashboards that we currently maintain.
Using Docker
Shell Completion
Contributing
Contributing Guidelines
Contributor Code of Conduct
License
Polkadot is GPL 3.0 licensed.