Use CountedStorageMap instead of StorageValue to manage the Events in frame-system
#22
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… frame-system Signed-off-by: linning <[email protected]>
| /// It could otherwise inflate the PoV size of a block. | ||
| /// | ||
| /// Events have a large in-memory size. Box the events to not go out-of-memory | ||
| /// just in case someone still reads them from within the runtime. | ||
| #[pallet::storage] | ||
| #[pallet::whitelist_storage] | ||
| #[pallet::disable_try_decode_storage] |
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I’m not sure I understand the docs here, they could either mean:
- we don’t need to migrate due to this attribute, or
- we need to remove this attribute in order to migrate
| #[pallet::whitelist_storage] | ||
| #[pallet::getter(fn event_count)] | ||
| pub(super) type EventCount<T: Config> = StorageValue<_, EventIndex, ValueQuery>; | ||
| CountedStorageMap<_, Identity, u32, Box<EventRecord<T::RuntimeEvent, T::Hash>>, OptionQuery>; |
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Should we use the type alias here instead?
| CountedStorageMap<_, Identity, u32, Box<EventRecord<T::RuntimeEvent, T::Hash>>, OptionQuery>; | |
| CountedStorageMap<_, Identity, EventIndex, Box<EventRecord<T::RuntimeEvent, T::Hash>>, OptionQuery>; |
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Please update the comment with map's key as well
| @@ -1916,7 +1896,8 @@ impl<T: Config> Pallet<T> { | |||
| /// execution else it can have a large impact on the PoV size of a block. | |||
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event_no_consensus() (above this comment) can be written to be much more efficient now, probably worth doing in case it impacts performance.
| /// It could otherwise inflate the PoV size of a block. | ||
| /// | ||
| /// Events have a large in-memory size. Box the events to not go out-of-memory | ||
| /// just in case someone still reads them from within the runtime. | ||
| #[pallet::storage] | ||
| #[pallet::whitelist_storage] |
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is it not possible to whitelist the storage prefix instead ?
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It is not supported by the upstream. It is possible to implement but is non-trivial.
| #[pallet::whitelist_storage] | ||
| #[pallet::getter(fn event_count)] | ||
| pub(super) type EventCount<T: Config> = StorageValue<_, EventIndex, ValueQuery>; | ||
| CountedStorageMap<_, Identity, u32, Box<EventRecord<T::RuntimeEvent, T::Hash>>, OptionQuery>; |
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Please update the comment with map's key as well
The other one is |
With
StorageValuetheEventsis a single array in the state that keep growing as more extrinsic is executed and more events append to this array, which makes execution and storage root calculation slower and slower as allocation/copying/hashing this array takes more and more time.Similar to how we handle
Pendingstate in frontier (see polkadot-evm/frontier#1575), this PR useCountedStorageMapto manage the event and so each event will present as a single value in the state.NOTE: this PR also removes
#[pallet::whitelist_storage]for theEventsstate because it is only supported forStorageValue, so if we re-run the benchmark with this PR the extrinsic will be charged weight for outputting event.TODO: the
Eventsstate is cleared in the initialization of the next block, TBC we may need to add migration to ensure theStorageValueevent is properly clear after the runtime upgrade.