Questions tagged [storagemap]
The storagemap tag has no usage guidance.
22
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0
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39
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How to get typed keys when querying a storage map via subxt
The example here https://github.com/paritytech/subxt/blob/master/subxt/examples/storage_iterating.rs
use subxt::{OnlineClient, PolkadotConfig};
#[subxt::subxt(runtime_metadata_path = "../...
- 3
0
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2
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37
views
Trying to store StorageMap<_, Twox64Concat, u128, (SomeStruct1, SomeStruct2<SomeType>), ValueQuery>
Getting the error:
the trait MaxEncodedLen is not implemented for SomeStruct
If I add MaxEncodedLen to the #[derive()] list it changes to this:
error[E0599]: no function or associated item named ...
1
vote
2
answers
32
views
How many ways are there to get all items stored in custom pallet
I would like to know what are the ways and how we can retrieve the all items stored in a custom pallet
I was having data structured in this way
#[derive(
Clone, Encode, Decode, Eq, PartialEq, ...
- 95
2
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1
answer
27
views
Data structure to choose for ordered items?
Can someone help me understand the difference b/w using a Vec (BoundedVec) instead of a StorageMap for storing ordered items? Basically inside a vector, the index would be an indicator of order ...
- 3,702
2
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1
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49
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Returning dynamic default values from StorageMap
I'm working with a StorageMap and want to return a dynamic default value based on the queried key when the key isn't found. Here's my attempt:
#[pallet::storage]
#[pallet::getter(fn asset)]
pub(super) ...
- 148
3
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1
answer
47
views
How we can iterate over all items in a storage map?
I have a storage in pallet
pub type Users<T: Config> = StorageMap<_, Blake2_128Concat, T::AccountId, User>;
I need to iterate over all the storage map to check a field data inside the ...
- 1,896
0
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1
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34
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Subscribe to storage map Entries?
On our substrate node using a storage double map. We are trying to subscribe to an entries query.
something like
const unsub = await api.query.system.balances.entries(ADDR, (res) => {
console....
- 341
3
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1
answer
17
views
Query chain for types in a storagemap
I want to get the meta function description of pallets storage maps. Returning an output like this:
{ Twox64Concat, [u8; 16], u32 } = query.storagemap(pallet: "template", storagemap: "...
- 319
3
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2
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28
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`BoundedBTreeMap` equivalent for `StorageMap`?
I'd like to set an upper limit on the size of a storage map. Is there a data structure that supports this check within its methods? Or has anyone defined their own wrapper data structure that performs ...
- 81
3
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2
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34
views
How to check if a `StorageMap` changed after the last access?
I am currently trying to iterate over a storage map over multiple blocks. For this I need to ensure that the StorageMap was not modified.
My plan is to derive a hash from the current StorageMap and ...
- 503
4
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1
answer
66
views
How to iterate a large `StorageMap` over multiple extrinsic calls?
Hey valuable Substrate community,
I am running into the problem that I need to iterate over an unbounded StorageMap. So I need an IterationLimit and use an extrinsic which gets called multiple times.
...
- 503
3
votes
1
answer
53
views
What does `no particular order` mean for storage iterations?
I am always curious what the documentation for the storage means when I see the following.
Enumerate all elements in the map in no particular order.
https://paritytech.github.io/substrate/master/...
- 503
2
votes
2
answers
52
views
Number of and writes of StorageMap drain
I was wondering about the number of reads and writes when draining a StorageMap which consists of n items. Is the answer (n, 1) or (n, n)?
- 167
2
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1
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39
views
Is migration required after adding an extra storage map to a pallet
From my understanding how the runtime store its state adding an extra storage variable like
pub Verified (get fn is_verified): map hasher(blake2_128_concat) us64 => ();
to a pallet that already ...
- 171
2
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2
answers
29
views
How to change one of the two `StorageDoubleMap` keys?
Say I have a StorageDoubleMap like this
pub type Users<T: Config> = StorageDoubleMap<_, Twox64Concat, Vec<u8>, Twox64Concat, Compact<u64>, Person<T::AccountId>,>;
where ...
- 183
3
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0
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55
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How does one figure what the total db reads & writes are for a clear_prefix call?
We need to perform a clear_prefix on a StorageDoubleMap every N blocks in on_initialize(), and we want to make sure the WeightInfo call properly accounts for read/writes. Should we simply pass unique ...
- 405
2
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1
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77
views
storage double map key deletion
Consider a substrate double map
pub Foo get(fn category_by_moderator): double_map
hasher(blake2_128_concat) T::K1, hasher(blake2_128_concat) T::K2 => T::V;
Suppose I want to delete all ...
- 171
1
vote
1
answer
83
views
Off-chain local storage map?
I have an off-chain worker that needs to write a HashMap<u64,Vec<u64>> to local storage. I can see how to write a single value using StorageValueRef and how I could possibly store a ...
- 530
0
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3
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187
views
How to mutate a `StorageDoubleMap` value?
I have StorageDoubleMap for ERC1155 balances u32 -> AccountId -> u32;
How can I mutate this map like balances[1][SomeAccountId] -= 4?
1
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0
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41
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How to encode data off-chain and push to child storage trie on Substrate?
I am creating the reward pool concept that allows users to claim reward pool. For scalability, we used Child Storage trie for different pool as trie_index.
Each trie_index has [wallet, ...
- 98
0
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1
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102
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When to use StorageDoubleMap `clear_prefix` vs `drain_prefix`?
Hey Substrate community,
there are two different methods to remove multiple items for one specific first key from a StorageDoubleMap. There is clear_prefix and drain_prefix. clear_prefix provides ...
- 503
2
votes
1
answer
95
views
What is the time complexity of StorageMap::clear()?
It appears in substrate this is O(n), but want to confirm since I believe hashbrown just wipes control bytes, which appears O(1).
Side note:
The problem I'm trying to solve is tracking a number of ...
- 484