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Questions related to memory use in Solidity or by nodes

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3answers
38 views

Should I use `storage` or `memory` when just reading the value and not changing state?

pragma solidity 0.4.24; contract Test { struct Book { uint id; } Book[] books; uint public status; constructor() public { books.push(Book(10)); } ...
0
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0answers
22 views

Problem creating struct inside a struct

Currently I am developing a game in solidity, I have 2 structs as follow: struct Team{ address owner; uint[] players; uint8[] moves; } struct Game{ Team challenger; Team ...
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0answers
15 views

How to use multidimensional memory array in solidity

I'm working with a project where I have requirement of multidimensional memory array. Here is basic structure of types and person(s) Id -Types -0 -Person1 -Person2 -1 -Person1 -...
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1answer
19 views

How can I get the content of storage and memory in my private chain?

I'm looking for some methods to know the content of storage and memory while the contract is running.Mayba some useful tools or abi ? By the way, the abi of geth, debug_writeMemProfile and ...
2
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1answer
41 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 ...
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1answer
54 views

Help with setting up Private POA(Clique) Ethereum Network

Geth Version : 1.8.12-stable-37685930 Testing on Amazon EC2 t2.large(8GB RAM) machine with Ubuntu 16.04 running. I am in need of setting up a multi node private POA(Clique) ethereum network. ...
0
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1answer
31 views

Solidity state variable resets to default inside function

For this project, I am coding smart contracts for Ethereum using Solidity. In the following code, the variable numCertificates should initially be 1. Nonetheless, newCertificateId is 0 when assigned. ...
3
votes
2answers
64 views

How to pop from (decrease the length of) a memory array in Solidity

I have a function that gets an address array from another contract, conditionally deletes the msg.sender from the array, then saves the new array back to that contract. Because the array backerList ...
2
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1answer
26 views

Always use “memory” for variables created within functions. Bad practice?

Is it bad practice to systematically use the memory keyword for variables declared within a function (other than constructor)?
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1answer
30 views

Compare memory pointers in Solidity

Is there a way to compare pointers in Solidity? I have two local variables: uint256[] memory a = new uint256[](256); uint256[] memory b = a; If I try a == b I get this compiler error: TypeError: ...
1
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1answer
161 views

The difference between contract address and wallet address

Disclaimer: this is a rather long question. To my understanding, contract address and wallet address are two profoundly different concepts, with the only thing in common being the fact that they are ...
0
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1answer
44 views

Why do arrays declared within functions reference storage point 0 by default?

According to the Solidity Documentation, for the following code, ". . . the compiler interprets x as a storage pointer and will make it point to the storage slot 0 by default. This has the effect ...
0
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1answer
37 views

how to replace an array in a mapping?

I'm learning solidity right now and making a dApp where users get paid to perform actions. Actions are paid based on certain criteria. Since I can't schedule a cron job on ethereum, I can only pay ...
1
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2answers
1k views

Why cryptokitties uses storage instead of memory?

There are a lot of explainations of storage and memory out there like this question or this question. But I'm wondering why cryptokitties for example uses storage instead of memory in many functions. ...
0
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0answers
41 views

Solidity memory pointer

Is there any way I can use a local parameter within multiple functions? The idea is to save gas when calling functions. A parameter wouldn't have to be copied and be returned every time. Here's some ...
0
votes
1answer
1k views

GPU'S Failed cannot create DAG

Last night everything is fine and then this morning I check my mining its's closed I think it was restarted or close accidentally then when I open my pool I have this error. ETH: 5 pools are ...
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0answers
20 views

How much storage does a smart contract use

I am trying to show the storage used by a deployed smart contract, I have a piece of code here that shows the first 10 indexes, let contractAddress = '0xf1f5896ace3a78c347eb7eab503450bc93bd0c3b' for (...
1
vote
2answers
31 views

value types(uint, bool, etc) as local variable is set to memory initially?

According to this answer, it says simpler variables like bool, uint, et cetera are not variable in length, and are therefore defaulted to memory, whereas this one mentions uint256 v; is default to ...
1
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0answers
29 views

Quorum failure - Failed to decode message from payload

We use in our project -JP Morgan Quorum (Ethereum based) bloackchain - with istanbul voting mode. We have 4 nodes (3 of them are validators - hard coded, nonchangable) And from time to time (...
0
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0answers
20 views

how can I initialized bytes1 array? is there maximum size to do that?

I want to initialize bytes1 array as follows, function myData(bytes1[10] _inData) public pure { bytes1[100] memory myCData = [ bytes1(0x01), 0x02, ......so on.. till 100 ]; } But I got out of ...
1
vote
2answers
428 views

How to fill dynamic in-memory array

For some reason solidity doesn't allow to push values into memory array Member "push" is not available in bytes32[] memory outside of storage. Here is sample contract code: pragma solidity ^0.4....
1
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0answers
19 views

Solidity VM memory management

I'm trying to do an external function call in assembly. So I have to prepare a memory area that store the input args. But where's the address that I should start with mstore? I mean, there are some ...
0
votes
1answer
110 views

I got “ TypeError: Storage location can only ..”

Here is my sample contract code, but I got an error, TypeError: Storage location can only be given for array or struct types. I just wannted to define some element of a structure in a function, ...
2
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1answer
58 views

Can marking object as 'memory' before pushing in Array save gas?

We have a struct: struct structEx { uint num; } And an array: structEx[] arr; Have a look at this code snippet, which just instantiates the struct and push: function f() public { structEx s =...
2
votes
1answer
181 views

Delete an entry in a mapping

To my understanding, delete x merely sets the value of x to the default value defined for the type of x (which is typically 0 in one way or another). For example: uint x = 1; delete x; // sets x = 0 ...
0
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0answers
21 views

Do I need to specify memory on the array variables?

Refer to the code below: function query() public returns (uint32[] memory) { uint32[] memory Bla; ... bla.... bla... bla... return Bla; } Do I really need to specify the memory keyword ...
1
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0answers
19 views

How load out data from blockchain when it occupies too much space?

If the blockchain working long enough it fills the memory of the mining device, how to load out the data and then rerun the system? and why does my mining device has different miner address every time ...
1
vote
1answer
116 views

convert bytes to uint8[8] using mstore()

I know how to convert bytes to uint8[8] using mload but mstore seemed like it could be more gas efficient. Is something like this possible? function bytesToUintArray(bytes input) returns (uint8[8])) ...
3
votes
1answer
54 views

Are balances of all accounts in memory or disk (storage)?

I simulated two contracts that sending balance to another and simply setting value of a variable(var a = 5;). In contrast my expectation, {var a = 5;} contract consumed more gas than the other. In my ...
0
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0answers
29 views

Where this data is stored where i deploy a contract? [duplicate]

I am very curious where are stored the data like (on Blockchain in smart contract) : -sender -caller Storage or memory ?
2
votes
1answer
40 views

Examples of functions limitations?

I coded different functions and didn't find a standard that define crystal clear how many variables you can use (fields, local or as parameters of modifiers inside this function? Do you know a ...
0
votes
1answer
2k views

Type error: memory is not implicitly convertible to expected type

I have a function that returns a list of BetProposition smart contracts: function getBetsForMatchup(uint matchupIdentifier) public returns (BetProposition[]) { return bets[matchupIdentifier]; ...
0
votes
2answers
411 views

Convert 'bytes memory' to 'bytes8'

In solidity, how can I convert bytes memory buffer to bytes8 type? Example: bytes8 buf2 = bytes8(memory_buf); // TypeError: Explicit type conversion not allowed
1
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1answer
567 views

Memory usage and limits for go-ethereum

geth (and swarm) seem to require a lot of memory, and there are also reports that they tend to an all you can eat approach to system limits. 1) What are the actual memory requirements for geth? 2) ...
3
votes
2answers
262 views

Stack too deep | Use memory array to store many “local” variables?

I have a contract that's doing a fairly complex calculation with some intermediate calculations, and I'm running into the "stack too deep" problem. I've tried to use a memory array within the ...
1
vote
2answers
41 views

Function that adds struct to an array in the blockchain does not execute when called by another function

I have a problem that's probably very basic, but I cannot seem to figure the issue out function _CreateBike(uint id, uint generation, string model, string ability, uint8 tier) internal returns(Bike){ ...
1
vote
2answers
163 views

Is the EVM memory model a word array or byte array?

The yellow paper says that the memory model for the EVM is a word-addressed byte array (YP 9.1), but when I run debug.traceTransaction in Geth, the memory looks more like an array of words, maybe a ...
0
votes
1answer
341 views

string memory[3] memory is not implicitly convertible to expected type bytes32[] storage ref

I have the following (array of bytes32 types): bytes32[] public allTokenSymbols = ["0x4554480000000000000000000000000000000000000000000000000000000000", "...
1
vote
0answers
193 views

For what data does Ethereum use Memory Database, and for what does it use Level Database

Ethereum uses two databases Memory database and Level Database. Is data stored in MemoryDatabase different than LevelDb? In what cases is one database used over other? The question is different from -...
0
votes
0answers
216 views

Does RAM memory overclock help increase hashrate?

I have a H110 D3A mofherboard, and 6 RX 470 4gb gpus on it. I have overclocked the gpus, and im wondering if overclocking the RAM memory would bring any benefits... i use a 8GB DDR4 memory stick. Any ...
0
votes
1answer
78 views

Writing to contract struct via function parameter, memory vs storage, “memory outside of storage”

This is my first contract ever (building on an own example learning case I made up). Given this Contract (simplified): unit gEval = 0; contract Group { struct Grp { string name; uint ...
1
vote
0answers
49 views

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 ...
1
vote
2answers
195 views

If we create a ERC20 compliant token, how do we optimize address-balance mapping storage if we have a large user base?

I assume that the address-balance mapping array in ERC20 is considered as a storage variable. So say if 1 million users start to use token A, then there would be 1 million entries in the balance ...
1
vote
1answer
932 views

Hidden problems in “set array to empty array to clear it” approach

I needed a way to clear a storage array in my contract. I've seen this answer, but I tried to think of different approach (My arrays are most probably will contain enormous amount of elements) and ...
2
votes
2answers
2k views

How to initialize an empty array inside a struct?

Is there a mistake in the way I initialize Bar b in the function foobar? contract Foo { struct Bar { address owner; uint[] x; } Bar[] public bars; function foobar(...
1
vote
2answers
424 views

Examples to clarify Storage vs Memory assignments / return parameters

Is there a mistake in funcB? I do not understand why/when to mention the variable name of the return parameter in the function signature. contract Foo { // State variables go to Storage uint[...
0
votes
1answer
445 views

Is there a maximum size for arrays in Solidity?

In my solidity code I define 3 arrays with around 700 elements inside. However, when I try to deploy the contract using Geth I am having the following error message: Error: oversized data undefined ...
4
votes
2answers
730 views

Assigning memory variable to storage variable, what happens?

I'm curious what happens if you try to do the next thing: contract C { Struct S { uint a; uint b; } mapping(address => s) structs; function updateStructs(S ...
2
votes
1answer
49 views

Is memory logged in a transaction?

Data in memory during a transaction is deleted when execution stops. This means this information is not stored in the contract state, but is the information that was in memory during the transaction ...
2
votes
1answer
71 views

Why is the cost of memory non-linear, while the cost of storage is linear?

Why is the cost of memory non-linear, while the cost of storage is linear? I wonder why the cost function of memory vs. storage differ? While storage is associated with a constant cost, this is not ...