Linked Questions

2 votes
1 answer

Where is storing events log? [duplicate]

I can't understand where are these events log data is stored? I can access to my logs by myContract.allEvents({ fromBlock: 2139049, toBlock: 'latest' }, function(error, event){ ...
user25688's user avatar
81 votes
13 answers

How to get contract internal transactions

I'd like to get the contract internal transactions like: I'm using web3 API. Is there any way to do it? Where do ...
Paul Exchange's user avatar
56 votes
3 answers

What is an Event?

What is an Event? Are they only used in Solidity? How are events defined? How are events initiated? Is there a standard term for an event's invocation (do you say an event "happened", "was called",...
Lee's user avatar
  • 8,468
23 votes
2 answers

Difference between a pruned and unpruned blockchain

At the Berlin Blockchain Meetup, Gustav Simonsson teased the Homestead release coming soon (tm) and we were discussing blockchain bloat and the current size of the Ethereum blockchain. We discussed ...
q9f's user avatar
  • 32.8k
27 votes
1 answer

Are events permanently stored and reliably available to contracts in the future?

I've seen this forum post about using Ethereum as an event store: Events in Solidity, using blockchain as eventstore. However, it doesn't seem conclusive. For instance it says: I confirmed with ...
Noah Thorp's user avatar
11 votes
4 answers

Proving the Existence of Logs to the Blockchain

To preface this: I'm not entirely sure this question makes any sense. Just a thought I had that I wanted to check the feasibility of. I'm pretty sure it is possible to use a Merkle proof to show that ...
Nate Rush's user avatar
  • 770
7 votes
1 answer

What are the benefits of using events over dedicated indexed variable?

Good day. I'm trying to grasp the concept of events in the EVM and I just can't understand what is the incentive of using events. Why not just use a dedicated public index that will hold information? ...
shultz's user avatar
  • 1,091
4 votes
2 answers

What do you mean by private and public smart contract in private blockchain ethereum? How to create it?

What I have done 1. A running private blockchain. 2. written and deploy a smart contract. 3. smart contract works fine on my private blockchain What I want 1. Only authorized account can access my ...
Imroz's user avatar
  • 871
0 votes
2 answers

How do oracle services interact with logs?

I am approaching blockchain and smart contracts for the first time and I have trouble understanding some concepts. I read this article
Mario Roma's user avatar
1 vote
1 answer

Storing state in log vs in contract variable

I've read somewhere says storing values in logs is cheaper than storing it in the contract's permanent storage. I wondered if it is the case. If yes, why? More general question: What is the pros and ...
Aydin's user avatar
  • 2,107
0 votes
1 answer

events can cause state change?

I am doing a simple HelloWorld class trying out several things including emitting events. My contract code is below: // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract HelloWorld { ...
CodeCalibre's user avatar
1 vote
0 answers

What happened if a Ethereum client do not have one event?

Reading this question, I understand that as long as you have the blockchain then you have all the events/logs. But if a dapp is reading data from a light Ethereum client, how will this light client ...
Suzana Maranhão Moreno's user avatar