Questions tagged [storage]
all questions regarding data and storage on the ethereum blockchain
125
questions with no upvoted or accepted answers
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1
answer
201
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Need help to understand storage costs
I have tried to implement a simple cellular automaton logic using two different ways to track the final state:
Track every iteration in a multi-dimensional array.
Store only the last two iterations.
...
- 135
4
votes
2
answers
3k
views
Declaring a memory array of storage pointers in Solidity
I would like to declare a variable as a memory array of pointers to storage arrays of uint256.
For example:
pragma solidity ^0.4.24;
contract A
{
uint256[] public array0;
uint256[] public ...
- 10.5k
3
votes
3
answers
866
views
How to view the amount of storage a contract uses?
Is it possible to view the amount of storage a smart contract uses from an existing tool? Or if not is it possible to determine it by making json rpc calls?
There are a few similar questions such as ...
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3
votes
0
answers
48
views
Why does a STORAGEADD op (SSTORE) add 80 bytes to state rather than 32?
According to this spreadsheet that Vitalik has referenced before, stating that it's what they used to determine gas fees for each opcode, a STORAGEADD opcode (presumably renamed to SSTORE) is ...
- 67
3
votes
2
answers
295
views
Set and delete storage variable in same tx
I did some poking around and didn't see an answer... and I figure someone knows this off the top of their head.
Question: what is the gas cost associated with setting and deleting a storage variable ...
- 211
3
votes
0
answers
628
views
Getting complete storage of a contract using geth client
I found at here, that it is possible for a client to get the value from storage of a contract at a particular index using eth.getStorageAt(contract_address, index) interface. I wanted to ask
Is it ...
- 357
3
votes
1
answer
88
views
CALL always throws exception on SSTORE
this.call(bytes4(keccak256("setGBA(uint32)")), 12);
How to call function by string name? I can't modify store in function. How to do this?
3
votes
1
answer
772
views
Regarding external file storage
Let's say you have a private blockchain, a DApp with an workflow to store and retrieve data from that blockchain. Now there is a need to store binary files and access it in a permissible way.
One way ...
- 1,804
2
votes
1
answer
45
views
Has Solidity Introduced Storage Optimization for Smaller Integer Types in Structs?
I am working on a project where storage efficiency is of utmost importance. Specifically, I have a scenario where I want to store an ID of type uint16 and a code of type uint8. The current plan is to ...
- 1,825
2
votes
0
answers
14
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How can my users store data using Ethereum-Wrapped Filecoin?
I'm building a data marketplace and want to have my users store their data (encrypted video, mostly) at their own expense. I can assume that they will have Ethereum available via Metamask, but not ...
- 197
2
votes
0
answers
46
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What's the benefit of encapsulating storage slots as structs?
Often times you'll see the following pattern for reading and writing to storage slots:
struct Slot {
address value;
}
...
function getSlot(bytes32 slot) returns (Slot storage s) {
assembly { s....
- 269
2
votes
0
answers
80
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Upgradable contracts - proxy storage allocation
So in general, for fixed size fields, storage is allocated (reserved) at time of contract deployment - as per my undestanding.
Now, we deploy a Proxy contract, and separately a couple versions of ...
- 121
2
votes
0
answers
68
views
I don't understand this part of the Ethereum Documentation (storageRoot)
This is from the account part of the Ethereum Docs, 4 fields of an account were described of which i am unable to understand this one.
(storageRoot)
- 115
2
votes
1
answer
108
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Decentralized Storage for sensitive data
As the title says, is there any decentralized storage technology for storing sensitive data like the personal information of users? Concretely, I am developing a Dapp on blockchain, where users have ...
- 121
2
votes
0
answers
147
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Solidity array has no SLOAD optimization
Suppose a function writes to storage, and then reads from the same storage location before it has been overwritten. In solidity 0.8.11 in these cases the SLOAD gets optimized away (there is 1 SSTORE ...
- 10.5k
2
votes
0
answers
187
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Why is the EVM designed to have "private variables"?
In EVM, one contract is able to read code and balance of any addresses. However, storage and nonce of other addresses is not accessible.
Since all states are public on the blockchain, why is EVM ...
- 141
2
votes
0
answers
246
views
Converting static variable to memory
I have the following code snippet in my contract, trying to call flashLoan from Aave.
address private constant LINK = 0x...;
function myFlashLoanCall(uint256 _amount, bytes memory _params) public {...
- 131
2
votes
0
answers
966
views
Running Geth full node + archiving on tiered storage possible?
I'm trying to run a geth full node with archiving for development\learning and custom analytics.
I have a physical Windows server running HyperV where I carved out the following VM specs:
24 vCPUs
...
2
votes
0
answers
45
views
Why `array[array.length] = elem;` fails for appending to a dynamic storage array in Solidity?
Consider the following contract:
pragma solidity ^0.8.0;
// SPDX-License-Identifier: WTFPL
contract Demo {
uint256[] public numbers;
function append(uint256 num) public {
...
- 4,604
2
votes
0
answers
254
views
How to initialize storage for smart contracts in the genesis block
I have a simple smart contract that will be added as part of genesis block. Need to initialize the field "message" with default value as constructor is not executed as part of genesis block ...
2
votes
0
answers
428
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How to store array parameter of a function to contract state?
I am trying to save an invoice to contract storage (see function addNewInvoice(..)) but I seem to be tripping over the data locations.
// SPDX-License-Identifier: private
pragma solidity >=0.7.0;
...
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2
votes
0
answers
113
views
Can we use Ethereum Swarm to store normal data other than blockchain or dapp data.
I want some basic data to be stored like name and city phone no etc.So just want to ask can I use ethereum swarm just to store file and make several node to create decentralized storage.
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2
votes
0
answers
264
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Gas cost of adding an item to a class-level (storage) array
I would like to make sure that the gas cost of adding an item to a (storage) array is constant, i.e., not dependent on the length of the array.
To my understanding, the relevant EVM operation is ...
- 26.2k
2
votes
0
answers
94
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Plasma: how were the UTXO bitmaps conceptualised and how will they be stored?
From the white paper, page 5:
We construct an interactive game whereby the exiting party attests to
a bitmap of participants’ ledger outputs arranged in an UTXO model
which requests a ...
- 18.5k
2
votes
0
answers
181
views
What is a cheap way to store mnemonic generator list of 1024 words in smart contract?
What is the cheapest way to store a list of 1024 words for a mnemonic generator, and why?
These ideas had a gas cost of 165720 GAS for a string array, and 42300 GAS for storing all the words in a ...
- 21
2
votes
0
answers
259
views
Decentralized File Storage on Ethereum white paper
I am reading white paper of Ethereum, and I am confused by this example of the Section. Decentralized File Storage, which is part of the Section. Applications:
The key underpinning piece of such a ...
- 201
2
votes
0
answers
48
views
Share private data and prevent data forwarding
Let's say A has some private medical records of patients and B is a pharmaceutical company who wants to view medical records from A to find out the effect of a particular drug on the patients (run a ...
- 21
2
votes
1
answer
122
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Decentralized Data Storage for IoT using Sia
For my Master research I want to make a proof-of-concept of decentralized data storage for an IoT scenario.
My idea is to receive measurement values from a raspberry pi and to store them using sia.
I ...
- 393
2
votes
0
answers
135
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Is it possible for a mapping to run out of space?
Can storage mappings in a contract run out of space? Say that mapping was keyed to an address and the value as the following struct:
User
bytes32 name
uint8 age
Theoretically, if there was a ...
- 399
2
votes
0
answers
166
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Extremely slow sync after moving to external drive (macOS; thunderbolt)
I was getting low on disk space so I decided to move the blockchain to an external drive with thunderbolt. I did it using Method 2 from this answer: In Mist browser how can I move the data (blockchain)...
user15943
2
votes
0
answers
185
views
Global storage array - setting length on declaration vs inside a function
I have a global storage array of 64 entries, which I declare as follows:
uint256[64] globalArr;
However, its length really depends on a constant variable in my code:
uint8 constant MAX_VAL = 63;
...
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2
votes
0
answers
205
views
In a private blockchain network, can we delete the first N blocks and reassign the N+1th block as the genesis block?
I am aware of the data loss caused by deleting the first N blocks. But I am curious to know whether such a task is possible or not. If so, how to practically implement it?
( I am using go-ethereum. ...
- 297
1
vote
1
answer
16
views
getting invalid opcode
this is my Solidity code
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
// pragma solidity ^0.8.0;
// pragma solidity >=0.8.0 <0.9.0;
contract SimpleStorage {
uint256 ...
1
vote
1
answer
475
views
Automatically getting implementation contract for eip 1967 proxy
Let's say I wanted to write code which looks at a smart contract, detects whether it is an upgradeable proxy, and then fetches the contract address.
Something like so:
const functionNames = abi.map((...
- 103
1
vote
0
answers
24
views
Struct string not saving to storage from mapping
Good morning guys,
I would like to get some help with some declaration that I am doing in my solidity contract, basically I want to have some data on my registry from a user, such as if it is admin, ...
- 66
1
vote
0
answers
147
views
Foundry : cast storage command storage slot argument posing length issue
When I try to get the private variable stored at storage slot 0 of the contract storage using the cast storage command,
cast storage <my-contract-address> 0 --rpc-url <my-rpc-url>
I get ...
- 11
1
vote
1
answer
56
views
Null keys when using `debug_storageRangeAt`
I'm currently trying to use the debug_storageRangeAt on a Hyperledger Besu RPC to extract the contract storage. For some contracts I get the expected response which is a list of keys and values:
"...
1
vote
1
answer
31
views
i have an upgradable smart contract with 3 mappings, i set only the first two in the initialize function
i have an upgradable smart contract with 3 mappings, i set only the first two in the initialize function .
pragma solidity ^0.8.0;
contract ContractA {
mapping(uint256 => address) public ...
- 368
1
vote
0
answers
40
views
"How to limit the function call for all users except those who have a special token with the address 'X'?"
hi i'm continuing to explore solidity. I wrote a contract which contains 4 functions: addAuthorizedAddress, removeAuthorizedAddress, storeData, retrieveData. The last two: storeData and retrieveData ...
- 127
1
vote
0
answers
94
views
Gas Optimisation of updating/reading struct in mapping
I'm trying to shave off a few thousand GAS from a transaction. I have the following struct in a mapping:
struct Data{
uint8[4] a
uint8[4] b
bytes5 z;
}
mapping(uint => Data) public ...
- 3,573
1
vote
0
answers
92
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Which contract's storage does SLOAD/SSTORE use?
A given SSTORE and SLOAD instruction uses storage from a certain smart contract. How can we know which contract that is, and do we need any additional data than the raw struct/opcode traces to find ...
- 121
1
vote
1
answer
40
views
Replace storage with the use of events. Considerations, risks?
I'm testing to not use state variables and relay on events and an external service to know the latest state and history of, in the simple example above, a Document. You can think about Document as a ...
- 11
1
vote
1
answer
68
views
Unable to reach storage struct via mapping
Gm,
I've got a smart contract for 2D board game purposes. There is a struct Unit
struct Unit
{
UnitType unitType;
uint16 x;
uint16 y;
int8 hp;
int8 dmg;
...
- 31
1
vote
0
answers
510
views
Retrieve Storage Variable Name given Storage Location and Contract Source
Is there any easy way to get the storage variable names provided you have the source code and the storage locations of the variables for a contract? For example, for the following contract I can use
...
1
vote
1
answer
71
views
Why does Ethereum state storage cost more than history storage?
According to this spreadsheet that Vitalik has referenced before, stating that it's what they used to determine gas fees for each opcode, state storage costs around 190 gas per byte while history ...
- 67
1
vote
1
answer
67
views
Max storage a mapping can hold
If I have a mapping that lets users store strings in a mapping ( by index). How many strings could the contract hold? Not worried about gas this will be on an L2
1
vote
2
answers
439
views
Why does this function not update my storage array?
Since reference types such as arrays are passed by reference by in Solidity, they pass a reference (pointer) to the value. Any change to that value will reflect on original value.
If this is the case, ...
- 1,682
1
vote
0
answers
29
views
Is it wrong to read or trust historical information from logs in client side?
I noticed one thing while learning Events/Logs from some sources. If I understand these sources correctly nodes can remove logs for effective memory usage.
If my client tries to read logs that do not ...
- 11
1
vote
0
answers
15
views
Is storage being passed to this newly created contract?
I'm looking at uniswapv3 code and noticed something peculiar. When uniswap creates a pool, it lays out parameters in storage and then immediately deletes them after the contract is created. Is this ...
- 135
1
vote
0
answers
12
views
Concept Check: Data Server Nodes, Fetch Nodes
I had this idea for a way to make it possible to run a MUCH MUCH smaller node but still mine on a chain. I don't know if there is anything useful in it, but decided I would post it here for feedback ...
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