Multi-phase elections solution resubmission #8290

coriolinus · 2021-03-08T13:31:59Z

Migration of #7976 to multi-phase-elections.

Fix issues such as paritytech/stakingops#130

Our OCW runner in staking is too conservative now. It only runs once at the beginning of the election window, and only attempts to submit once. If for any reason (e.g. secondary/primary slot overlap, fork and rollback) all validators temporarily think that a solution is submitted, they will all drop their computed solution and never try again. In essence, they will attempt to submit it, which will fail because there is already a good solution on-chain, and the process ends. In this scenario, if the submitted solution gets reverted, we are left with nothing, and thus a heavy on-chain election.

This is a minimal patch to fix the situation. OCW will compute, save and submit the solution initially, and until the end of the election window periodically try to re-submitted the saved solution, if none is stored yet.

polkadot companion: paritytech/polkadot#2648

This is a much smaller diff than that PR contained, but I think it contains all the essentials.

bin/node/runtime/src/lib.rs

frame/election-provider-multi-phase/src/lib.rs

frame/election-provider-multi-phase/src/unsigned.rs

kianenigma

All good, except: https://github.com/paritytech/substrate/pull/8290/files#r618179176

should address https://github.com/paritytech/substrate/pull/8290/files#r617533358 restructures how the checks are sequenced, which simplifies legibility.

gui1117

looks good to me

coriolinus · 2021-05-03T07:36:31Z

bot merge

ghost · 2021-05-03T07:36:35Z

Waiting for commit status.

ghost · 2021-05-03T08:04:52Z

Merge aborted: Checks failed for 6ae73c4

coriolinus · 2021-05-03T10:48:58Z

bot merge

ghost · 2021-05-03T10:49:03Z

Trying merge.

* Companion for Multi-phase elections solution resubmission paritytech/substrate#8290 * update Substrate Co-authored-by: parity-processbot <>

This reverts commit 92c15dd.

* not climate * explain the intent of the bool in the unsigned phase * remove glob imports from unsigned.rs * add OffchainRepeat parameter to ElectionProviderMultiPhase * migrate core logic from paritytech#7976 This is a much smaller diff than that PR contained, but I think it contains all the essentials. * improve formatting * fix test build failures * cause test to pass * Apply suggestions from code review Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> * collapse imports * threshold acquired directly within try_acquire_offchain_lock * add test of resubmission after interval * add test that ocw can regenerate a failed cache when resubmitting * ensure that OCW solutions are of the correct round This should help prevent stale cached solutions from persisting past the election for which they are intended. * add test of pre-dispatch round check * use `RawSolution.round` instead of redundantly externally * unpack imports Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> * rename `OFFCHAIN_HEAD_DB` -> `OFFCHAIN_LOCK` * rename `mine_call` -> `mine_checked_call` * eliminate extraneous comma * check cached call is current before submitting * remove unused consts introduced by bad merge. Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com> * resubmit when our solution beats queued solution * clear call cache if solution fails to submit * use local storage; clear on ElectionFinalized * Revert "use local storage; clear on ElectionFinalized" This reverts commit 4b46a93. * BROKEN: try to filter local events in OCW * use local storage; simplify score fetching * fix event filter * mutate storage instead of setting it * StorageValueRef::local isn't actually implemented yet * add logging for some events of interest in OCW miner * rename kill_solution -> kill_ocw_solution to avoid ambiguity * defensive err instead of unreachable given unreachable code * doc punctuation Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> * distinguish miner errors between "out of date" and "call invalid" * downgrade info logs -> debug * ensure encoded call decodes as a call * fix semantics of validation of pre-dispatch failure for wrong round * move score check within `and_then` * add test that offchain workers clear their cache after election * ensure that bad ocw submissions are not retained for resubmission * simplify fn ocw_solution_exists * add feasibility check when restoring cached solution should address https://github.com/paritytech/substrate/pull/8290/files#r617533358 restructures how the checks are sequenced, which simplifies legibility. * simplify checks again Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>

* Companion for Multi-phase elections solution resubmission paritytech/substrate#8290 * update Substrate Co-authored-by: parity-processbot <>

coriolinus added 5 commits March 5, 2021 10:39

not climate

62e1854

explain the intent of the bool in the unsigned phase

9a8c4a2

remove glob imports from unsigned.rs

19d7251

add OffchainRepeat parameter to ElectionProviderMultiPhase

02ad14b

migrate core logic from #7976

f6a0fd9

This is a much smaller diff than that PR contained, but I think it contains all the essentials.

coriolinus self-assigned this Mar 8, 2021

github-actions bot added the A3-in_progress Pull request is in progress. No review needed at this stage. label Mar 8, 2021

coriolinus changed the title ~~Prgn runtime resubmit~~ Multi-phase elections solution resubmission Mar 8, 2021

coriolinus added B0-silent Changes should not be mentioned in any release notes C1-low PR touches the given topic and has a low impact on builders. labels Mar 8, 2021

kianenigma reviewed Mar 8, 2021

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coriolinus added 4 commits March 8, 2021 15:07

improve formatting

59a0fb4

fix test build failures

4612d07

cause test to pass

c8ccbe9

Merge remote-tracking branch 'origin/master' into prgn-runtime-resubmit

7e4408f

coriolinus marked this pull request as ready for review March 10, 2021 11:30

github-actions bot added A0-please_review Pull request needs code review. and removed A3-in_progress Pull request is in progress. No review needed at this stage. labels Mar 10, 2021

paritytech-ci added the D2-breaksapi label Mar 10, 2021

github-actions bot added the A7-needspolkadotpr label Mar 10, 2021

coriolinus added the D9-needsaudit 👮 PR contains changes to fund-managing logic that should be properly reviewed and externally audited label Mar 10, 2021

kianenigma reviewed Mar 15, 2021

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kianenigma reviewed Mar 15, 2021

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kianenigma approved these changes Apr 22, 2021

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coriolinus added 3 commits April 23, 2021 13:16

simplify fn ocw_solution_exists

840bad3

add feasibility check when restoring cached solution

8eaf481

should address https://github.com/paritytech/substrate/pull/8290/files#r617533358 restructures how the checks are sequenced, which simplifies legibility.

simplify checks again

f4b52f0

gui1117 approved these changes Apr 23, 2021

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kianenigma mentioned this pull request Aug 24, 2023

Ensure saved offchain solution matches creation snapshop paritytech/polkadot-sdk#462

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jakoblell added D1-audited 👍 PR contains changes to fund-managing logic that has been properly reviewed and externally audited and removed D9-needsaudit 👮 PR contains changes to fund-managing logic that should be properly reviewed and externally audited labels Apr 29, 2021

Merge remote-tracking branch 'origin/master' into prgn-runtime-resubmit

6ae73c4

github-actions bot added the A7-needspolkadotpr label May 3, 2021

ghost merged commit 92c15dd into master May 3, 2021

ghost deleted the prgn-runtime-resubmit branch May 3, 2021 10:49

kianenigma added a commit that referenced this pull request May 15, 2021

Revert "Multi-phase elections solution resubmission (#8290)"

04e03ce

This reverts commit 92c15dd.

kianenigma added a commit that referenced this pull request May 15, 2021

Revert "Multi-phase elections solution resubmission (#8290)"

0c258bc

This reverts commit 92c15dd.

MRamanenkau mentioned this pull request Sep 20, 2022

Feature/update to polkadot v0 9 1 Cerebellum-Network/pos-network-node#147

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Multi-phase elections solution resubmission #8290

Multi-phase elections solution resubmission #8290

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Multi-phase elections solution resubmission #8290

Multi-phase elections solution resubmission #8290

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