[async_backing] Bump ParachainHost to api version 10 on polkadot #222
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This will enable async-backing subsystems on polkadot, the relaychain would work in legacy mode where only candiddates built on top of pervious relay chain are activated. - Had to bring an unrelated change as well `minimum_backing_votes` because that was the v6, we can't skip versions, the value of that configuration on polkadot is 2, so that's what is going to be used after this runtime update. Changes have been running on kusama, so I would. Async backing subsytems is a major change in the way collator-protocol and the backing work, so there are still some unknowns if this is completely bug free. It has been running on kusama for a month already, but not without issues: - Validators that did not upgrade to compatible versions will not be able to participate in backing, so if enough of those are randomly picked that group won't be able to back anything. With backing_group_size = 5 and minimum_backing_votes = 2, 10% validator not upgraded that chance is about 2.5%. - Additionally, same un-upgraded groups won't be able to include the backing votes on chain when they author blocks, so 10% of the blocks won't back any candidates. - We are still not sure if item 2) from here paritytech/polkadot-sdk#3314 (comment) is caused by async backing, the observable issue is sometimes after restart/upgrade some validators are getting 0 rewards and apparently they are not backing anything. Signed-off-by: Alexandru Gheorghe <alexandru.gheorghe@parity.io>
Signed-off-by: Alexandru Gheorghe <alexandru.gheorghe@parity.io>
alexggh
changed the title
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@alexggh can you please finish the pr, to make it reviewable? |
Signed-off-by: Alexandru Gheorghe <alexandru.gheorghe@parity.io>
Done, so that is clear for everyone we still have the risks presented in the description and if from now till 1.2 release gets enacted we would find any blocker issue, we would have to cancel 1.2 release and remove this changes or add a fix on top. |
| fn disabled_validators() -> Vec<ValidatorIndex> { | ||
| parachains_vstaging_api_impl::disabled_validators::<Runtime>() | ||
| } | ||
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| fn node_features() -> NodeFeatures { | ||
| parachains_vstaging_api_impl::node_features::<Runtime>() | ||
| } | ||
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| fn approval_voting_params() -> ApprovalVotingParams { | ||
| parachains_vstaging_api_impl::approval_voting_params::<Runtime>() | ||
| } |
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not a blocker as we can do it as follow-up cleanup PR, but we should not use use vstaging runtime impls on Polkadot and instead stabilize them once tested on Kusama
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Ok, then I'll clean this up with a follow up PR.
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/merge |
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e.g. push empty commit and wait for CI again or find someone who can restart that job: https://github.com/polkadot-fellows/runtimes/actions/runs/8248792955/job/22560279689?pr=222, maybe @ggwpez could help? |
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This will enable async-backing subsystems on polkadot, the relaychain would work in legacy mode where only candiddates built on top of pervious relay chain are activated.
Notes
minimum_backing_votesbecause that was the v6, we can't skip versions, the value of that configuration on polkadot is 2, so that's what is going to be used after this runtime update. Changes have been running on kusama.disabled_validators,node_features,approval_voting_paramsare not related with async-backing, but given they are low risk, we decided to include them as well, see comments.Known risks
Async backing subsytems is a major change in the way collator-protocol and the backing work, so there are still some unknowns if this is completely bug free. It has been running on kusama for a month already, but not without issues:
Validators that did not upgrade to compatible versions will not be able to participate in backing, so if enough of those are randomly picked that group won't be able to back anything. With backing_group_size = 5 and minimum_backing_votes = 2, 10% validator not upgraded, that chance is about 2.5%.
Additionally, same un-upgraded groups won't be able to include the backing votes on chain when they author blocks, so 10% of the blocks won't back any candidates.
We are still not sure if item 2) from here Kusama parachains block production slowed down paritytech/polkadot-sdk#3314 (comment) is caused by async backing, the observable issue is sometimes after restart/upgrade some validators are getting 0 rewards and apparently they are not backing anything.