Unlimited number of nominators eligible for Rewards payout #13059

Ank4n · 2023-01-04T02:53:06Z

closes paritytech/polkadot-sdk#439 and paritytech/polkadot-sdk#473.
polkadot companion: paritytech/polkadot#6765

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. Practically, this number would be the same as MaxNominatorRewardedPerValidator or lower.

The PR also intends to be mostly backward compatible.

Note about the release

This PR introduces a new storage item MaxExposurePageCount which defaults to minimum value of 1 when not set. This means functionally, the pallet will continue to work exactly as before after this release. To enable paged rewards payout, MaxExposurePageCount can be increased to a bigger number by OpenGov for each runtime separately.

How payouts would look 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.

Lets look at an example scenario.
Given an active validator on Kusama had 1100 nominators, MaxExposurePageCount set to 10 and 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 explicitly.

Important to 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 encourages the validator to payout all the exposure pages.

Storage Changes

Added

ErasStakersOverview
ClaimedRewards
ErasStakersPaged

Deprecated

The following can be cleaned up after 84 eras. Tracker issue for cleaning up.

ErasStakers.
ErasStakersClipped.
StakingLedger.claimed_rewards, renamed to StakingLedger.legacy_claimed_rewards.

Config Changes

Renamed MaxNominatorRewardedPerValidator to MaxExposurePageSize.
New item MaxExposurePageCount

TODO

Follow up issues

Staking runtime apis to help with paged reward payouts polkadot-sdk#426

frame/staking/src/pallet/impls.rs

frame/staking/src/pallet/mod.rs

Ank4n · 2023-02-22T17:41:58Z

bot bench $ pallet dev pallet_staking

command-bot · 2023-02-22T17:42:03Z

@Ank4n https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/2431168 was started for your command "$PIPELINE_SCRIPTS_DIR/commands/bench/bench.sh" pallet dev pallet_staking. Check out https://gitlab.parity.io/parity/mirrors/substrate/-/pipelines?page=1&scope=all&username=group_605_bot to know what else is being executed currently.

Comment bot cancel 52-ff52a743-ddb4-4724-b638-d28192f1e805 to cancel this command or bot cancel to cancel all commands in this pull request.

… HEAD

command-bot · 2023-02-22T18:57:06Z

@Ank4n Command "$PIPELINE_SCRIPTS_DIR/commands/bench/bench.sh" pallet dev pallet_staking has finished. Result: https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/2431168 has finished. If any artifacts were generated, you can download them from https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/2431168/artifacts/download.

Ank4n · 2023-02-22T19:38:47Z

bot bench $ runtime westend-dev pallet_staking

command-bot · 2023-02-22T19:38:52Z

@Ank4n "$PIPELINE_SCRIPTS_DIR/commands/bench/bench.sh" runtime westend-dev pallet_staking (https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/2431633) was cancelled in #13059 (comment)

Ank4n · 2023-02-22T19:39:11Z

bot cancel

command-bot · 2023-02-22T19:39:16Z

@Ank4n Command "$PIPELINE_SCRIPTS_DIR/commands/bench/bench.sh" runtime westend-dev pallet_staking has finished. Result: https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/2431633 has finished. If any artifacts were generated, you can download them from https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/2431633/artifacts/download.

kianenigma · 2023-02-24T15:41:11Z

bin/node/runtime/src/lib.rs

@@ -596,7 +597,7 @@ impl pallet_fast_unstake::Config for Runtime {
 	type Staking = Staking;
 	type MaxErasToCheckPerBlock = ConstU32<1>;
 	#[cfg(feature = "runtime-benchmarks")]
-	type MaxBackersPerValidator = MaxNominatorRewardedPerValidator;
+	type MaxExposurePageSize = MaxExposurePageSize;


This can come from T::Staking, still feature gated ofc.

kianenigma · 2023-02-24T15:41:50Z

frame/fast-unstake/src/benchmarking.rs

@@ -74,7 +74,7 @@ fn setup_staking<T: Config>(v: u32, until: EraIndex) {
 		.collect::<Vec<_>>();

 	for era in 0..=until {
-		let others = (0..T::MaxBackersPerValidator::get())
+		let others = (0..T::MaxExposurePageSize::get())


Suggested change

let others = (0..T::MaxExposurePageSize::get())

let others = (0..T::Staking::MaxExposurePageSize::get())

kianenigma · 2023-02-24T15:48:46Z

frame/staking/CHANGELOG.md

+
+## [14]
+
+### Added


Nice, much better.

Ank4n · 2023-03-01T00:43:31Z

I got couple of feedbacks about lot of noise in this PR caused by upstream merges. Created a new PR with rebased changes here.

paged exposure skeleton

acab2d1

github-actions bot added the A3-in_progress Pull request is in progress. No review needed at this stage. label Jan 4, 2023

Ank4n commented Jan 4, 2023

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Ank4n commented Jan 4, 2023

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Ank4n changed the title ~~paged exposure skeleton~~ [WIP] Paged exposure skeleton Jan 4, 2023

Ank4n changed the title ~~[WIP] Paged exposure skeleton~~ [WIP] paged reward payouts Jan 4, 2023

Ank4n commented Jan 4, 2023

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frame/staking/src/pallet/mod.rs Outdated Show resolved Hide resolved

insignificant changes

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Ank4n added 13 commits January 5, 2023 15:10

Merge branch 'master' into ankan/paged-rewards

8e6db42

add note on usage of twox hash

0cabf55

Merge branch 'master' into ankan/paged-rewards

00bc992

impl paged exposure

f65d7b6

paged as exposure function

e7f299c

add test for paging exposure

b3f58d6

remove commented fn

661fab0

cargo fmt

06d83fb

more fmt

02e3ffc

remove unnecessary bound

c924bfc

add wrapper struct and refactor

108cd16

create temp fn that checks both ledger and new claimed_rewards

e14eab3

incomplete, paged extrinisic to pay stakers

70b8c7f

Ank4n commented Jan 9, 2023

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Ank4n commented Jan 9, 2023

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Ank4n commented Jan 9, 2023

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Ank4n commented Jan 9, 2023

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Ank4n mentioned this pull request Jan 9, 2023

[do not merge] Decouple rewards from ledger #13023

Closed

5 tasks

Ank4n requested a review from gpestana January 9, 2023 07:19

Ank4n added 2 commits January 9, 2023 08:34

Merge branch 'master' into ankan/paged-rewards

484dad8

fix names

eac23e0

Ank4n added 6 commits February 20, 2023 23:40

bounded ExposureOverview

06627f0

remove unused fn

89820f9

ErasStakers backward compatible test

66c8fe1

fmt

b5fa46e

update changelog

12ed262

Use NMap for ErasStakersPaged

14bc8b3

Ank4n mentioned this pull request Aug 24, 2023

Staking runtime apis to help with paged reward payouts paritytech/polkadot-sdk#426

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4 tasks

doc update

6ac7961

Merge branch 'master' of https://github.com/paritytech/substrate into…

af01a1f

… HEAD

Ank4n mentioned this pull request Feb 22, 2023

[Companion] Unlimited number of nominators eligible for Rewards payout paritytech/polkadot#6765

Open

2 tasks

".git/.scripts/commands/bench/bench.sh" pallet dev pallet_staking

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rename to consistent names

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Ank4n requested review from gpestana and kianenigma February 22, 2023 20:40

kianenigma reviewed Feb 24, 2023

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frame/staking/CHANGELOG.md

## [14]

### Added

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Nice, much better.

some docs

2aa08d6

This was referenced Feb 28, 2023

Unlimited number of nominators eligible for Rewards payout (rebased) #13497

Closed

[NPoS] Unlimited number of nominators eligible for Rewards payout #13498

Open

Ank4n closed this Mar 1, 2023

louismerlin removed the D9-needsaudit 👮 PR contains changes to fund-managing logic that should be properly reviewed and externally audited label May 4, 2023

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Unlimited number of nominators eligible for Rewards payout #13059

Unlimited number of nominators eligible for Rewards payout #13059

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Ank4n commented Mar 1, 2023

	let others = (0..T::MaxExposurePageSize::get())
	let others = (0..T::Staking::MaxExposurePageSize::get())

Unlimited number of nominators eligible for Rewards payout #13059

Unlimited number of nominators eligible for Rewards payout #13059

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Ank4n commented Jan 4, 2023 • edited Loading

Context

Note about the release

How payouts would look like after this change

payout_stakers

payout_stakers_by_page

Important to note

Storage Changes

Added

Deprecated

Config Changes

TODO

Follow up issues

Ank4n commented Feb 22, 2023

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