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Questions tagged [memory]

Questions related to memory use in Solidity or by nodes

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What is the maximum storage size to store number of addresses in array? [duplicate]

I want to map multiple addresses using one address by doing this: mapping (address => arrayOfAddresses[]) mappingName; What is the maximum size of addresses I can store in that array?
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2answers
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how does Storing and Fetching data works in Smart contracts [closed]

Please help me out with these questions. 1)Where does the contract stores the data? 2)when we access the value of a variable form of a contract, how does it retrieve the latest value? 3)how is the ...
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1answer
42 views

error: data location must be storage or memory for parameter in funtion but none was given solidity [duplicate]

pragma solidity ^0.5.0; contract Election{ //model a candidates struct candidate { uint id; string name; uint votecount; } //store candidates //fetch candidate mapping(uint =...
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2answers
52 views

How much data can I store in a smart contract, what is the cost and how it is implemented?

If I suppose I use a smart contract as a database, how much data can I store? speaking only of strings and integers, save them in contract data structures does it cost in addition to the gas used for ...
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1answer
16 views

Cannot retrieve data from smartcontract during tests

I am writing truffle tests for my smart contract solidity version 0.4.24. The tests are emitting events to write data to memory through smart contract. But I am unable to retrieve data from functions. ...
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1answer
60 views

Switching from 'storage' to 'memory' increases the gas-cost

I've read several related answers and blog posts, all of them suggesting that for the sake of reading complex state variables (i.e., arrays and structures), one should always prefer declaring the ...
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2answers
56 views

How could Solidity 0.5.0 dynamic sized parameters be declared as storage?

As I understand it 'memory' in the EVM is a byte array and cannot be dynamically resized, whereas 'storage' is able to be resized. What is happening when a parameter is declared as storage. Where is ...
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318 views

FATAL ERROR: Rebalance Allocation failed - process out of memory

So while running truffle compile for my contracts on AWS Ubuntu server I got the following error: <--- Last few GCs ---> [17055:0x3985730] 11958 ms: Scavenge 511.7 (553.4) -> 506.9 (553.4) ...
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26 views

Why is an address changing when I add it to an array?

I'm encountering a memory / storage issue (I think) w/ an array of addresses where I want to swap out one address with another. Here's how I've initialized the array: address[] public maintainers; ...
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0answers
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How to get live mempool transactions whitout full blokchain

I just want to analyse all mempool txs in realtime. I cant use an api because after several requests my ip gets blocked for some minutes, so I dont get the txs in this time. Thank you for help.
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1answer
7k views

TypeError: Data location must be “storage” or “memory” for parameter in function, but none was given

/// @dev Adds a new transaction to the transaction mapping, if transaction does not exist yet. /// @param destination Transaction target address. /// @param value Transaction ether value. /// @param ...
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2answers
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Where are local variables of Primitive (Elementary) data types stored in Solidity

Though in the latest solidity compiler versions, it has been made clear that for reference variables local to a function, one needs to now explicitly mention its location modifier (memory, storage), ...
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1answer
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Finding the memory position of mapping(address => uint) using JavaScript

I am wanting to read data from internal mappings with the following structures: mapping (uint256 => uint256) internal nums; mapping (address => uint256) internal addrToInt; Finding the memory ...
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2answers
93 views

What is the proper pattern to use a temporary variable and ensure it gets stored?

A contract has a state variable, which is complex. For the example, lets say it is a mapping of structs. Inside a method, I want to access that and store the changes. Like so: contract FooManager { ...
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getLogs RPC makes filters?

I am stuggling with memory explosion issue of Parity on my EC2 instance. The memory usage of it keeps increasing gradually. I suspect that getLogs API call makes some garbage on the node. But I ...
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1answer
167 views

memory keyword in function argument

What does the memory keyword in the argument of a function do? pragma solidity 0.4.24; pragma experimental "ABIEncoderV2"; contract Conditional { struct Condition { address to; bytes4 ...
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1answer
206 views

Creating a 2D in-memory array in Solidity

I'm trying to work with 2D in-memory arrays in Solidity, in which the size is not known at compile time. I've noticed that if I define the array size as a constant, then I can use this syntax, which ...
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3answers
164 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)); } ...
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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
43 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 ...
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1answer
263 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
486 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. ...
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1answer
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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. ...
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2answers
144 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 ...
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1answer
225 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
125 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: ...
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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 ...
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1answer
218 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 ...
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1answer
93 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 ...
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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. ...
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0answers
117 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 ...
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1answer
3k 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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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 (...
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3answers
180 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 ...
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114 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 (...
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2answers
2k 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....
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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 ...
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1answer
467 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, ...
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1answer
188 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 =...
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1answer
471 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 ...
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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 ...
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2answers
299 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])) ...
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1answer
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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 ...
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1answer
70 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 ...
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1answer
5k 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]; ...
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2answers
962 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
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1answer
1k 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) ...
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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 ...
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2answers
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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){ ...
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2answers
299 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 ...