Questions tagged [storage]
Questions about storing and accessing stored data on a Substrate blockchain.
19 questions
11
votes
2
answers
459
views
How to use bounded vector for storage
I'm trying to use BoundedVec from frame_support for one of my storage items like this,
pub(super) type Payloads<T: Config> = StorageMap<_, Blake2_128Concat, T::BlockNumber, Vec<Payload>,...
- 135
2
votes
1
answer
124
views
BoundedVec on ink!
BoundedVec is a vector where the length of the queue is always bounded, which is better than Vec for storage because it has a defined a maximum length.
I recommend this StackExchange questions to ...
- 5,767
2
votes
1
answer
114
views
How to selectively populate state from a snapshot of one chain onto another?
Goal
To use a full snapshot at some block height of one chain and selectively pull in select parts of this state.
Use cases
Migrating state from another chain. Example:
A snapshot of only assets ...
- 1,852
13
votes
2
answers
385
views
Is there a limit to the size of a map in Pallet storage?
If we are using a single or double maps in our pallets to store data on-chain, is there a limit to the number of records or size of one individual map?
I understand we should be storing the minimal ...
- 345
11
votes
1
answer
323
views
How expensive is it to access storage items?
How expensive are storage reads and writes?
Does the cost depend on the size of the item?
- 9,322
8
votes
1
answer
243
views
Generating a Storage Key when making an RPC request
I'm trying to make an RPC call to a Substrate node, but I can't generate a proper Storage Key. The Module and Method parts are fine, the problem is the Twox64Concat part. The sp_core::twox_64 of value ...
- 460
8
votes
2
answers
258
views
What's the overhead associated with the `#[transactional]` macro?
Substrate has a macro, #[transactional], to ensure that any modifications to storage are not persisted in case of an error during execution.
I imagine there's some sort of caching done before ...
- 1,091
7
votes
1
answer
270
views
Prepare pallets for Weights v2
I am trying to prepare the pallets for Weights v2 at Encointer and a couple of questions arose.
Where can I find documentation on what exactly has to be done in terms of bounded types?
What is the ...
- 83
6
votes
1
answer
122
views
What are good use cases for child tries
After reading the substrate documentation:
Child tries are useful when you want your own independent trie with a
separate root hash that you can use to verify the specific content in
that trie. ...
- 531
5
votes
1
answer
190
views
Migrate keytype of StorageMap without breakin API
Assume we have a StorageMap MyMap of which we want to extend the type of the decoded keys from KeyTypeOld to an enum including the old type as well as a new one.
Before
pub type MyMap = StorageMap<...
5
votes
1
answer
283
views
How to weight `on_initialize`?
Is there any best practice how to count the weights in on_initialize correctly?
I read through the Polkadot and Substrate on_initialize weight calculations and couldn't always figure out: When to ...
- 543
5
votes
1
answer
139
views
Issue with #[pallet::generate_storage_info]
I was digging into substrate's storage_info macro https://docs.substrate.io/v3/runtime/macros/#palletgenerate_storage_info.
To get hands dirty checked code from
https://github.com/yourarj/substrate-...
- 327
4
votes
2
answers
96
views
Does each block save a copy of a Storage item?
This is what I read from the substrate storage docs: https://docs.substrate.io/v3/runtime/storage/
Runtime storage allows you to store data in your blockchain that is
persisted between blocks and can ...
- 1,009
4
votes
1
answer
131
views
How do I recover quickly if the number of healthy nodes for my parachain reaches zero?
I'm particularly interested in the role of backups and state stored on disk in the recovery process. In terms of preparations, we are early enough in our project lifecycle to put in place whatever ...
- 141
3
votes
1
answer
132
views
What is Dev Mode? And how can I use it?
I heard there is something called Dev Mode in Substrate for pallet development.
What is Dev Mode? And how can I use it?
- 8,455
2
votes
1
answer
71
views
Reclaim used space of a removed StorageItem on a live chain
I am changing the collator_selection pallet by removing the LastAuthoredBlock StorageItem and adding an unrelated one, so although the chain is live, no data migration is needed.
What happens with the ...
- 121
2
votes
1
answer
128
views
Forked Parity pallet, didn't migrate storage, deployed to chain. How to clear original storage from the live chain?
We started a chain using pallet_collator_selection and later forked it.
Both the original and the forked pallet use the LastAuthoredBlock StorageItem.
We did not execute a storage migration from the ...
- 121
0
votes
1
answer
103
views
Runtime API to collect values in StorageMap
I'm trying to retrieve all values in my StorageMap defined as such in my pallet:
#[pallet::storage]
#[pallet::getter(fn submitted_tasks)]
pub type SubmittedTasks<T: Config> =
StorageMap<_,...
- 291
0
votes
2
answers
67
views
How to get the validators list?
Is it possible to get the list of validators which validate a particular block?
For instance, let's say we have at block 10 and if this block is finalised then I need to find the list of validators ...
- 2,100