> For the complete documentation index, see [llms.txt](https://totochain.gitbook.io/totochain/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://totochain.gitbook.io/totochain/toto-chain-faq/block-finality-and-network-performance.md).

# Block Finality and Network Performance

## **What is block finality, and how is it achieved on the Toto Chain?**

Block finality refers to the process of determining which block is the definitive, irreversible part of the blockchain. On the Toto Chain, block finality is achieved through **GRANDPA**, a finality gadget that allows validators to vote on the next block. A transaction is considered final after a few blocks at most​.

***

## **What are "GRANDPA" and "BABE"?**

* **GRANDPA (GHOST-based Recursive Ancestor Deriving Prefix Agreement)**: This is the finality mechanism used by the Toto Chain. It finalizes blocks asynchronously by allowing validators to vote on the chain's state.
* **BABE (Blind Assignment for Blockchain Extension)**: While not explicitly mentioned in the documents, BABE is commonly used alongside GRANDPA in Substrate-based chains to provide block production. Instead of a pure Proof-of-Work or Proof-of-Stake system, BABE assigns block production slots randomly among validators​.

***

## **How long does it take for a transaction to be considered final?**

A transaction is considered final after a few blocks. Since the block time on the Toto Chain is **3 seconds**, finality would take a short period, depending on how many blocks are required for confirmation​.

***

## **What happens in cases of block reorganization or forks?**

In the case of block reorganization or forks, the chain follows the **longest chain rule**. This means that if two competing blocks exist, the chain will continue building on the longer branch, discarding the shorter one. GRANDPA ensures that once a block is finalized, it cannot be reversed​.

***

## **What is the transaction throughput of the Toto Chain (e.g., transactions per second)?**

The documents do not provide a specific transactions-per-second (TPS) metric, but since the **block time is 3 seconds**, and assuming the chain follows Substrate’s standard optimization, TPS could be in the range of **hundreds to a few thousand transactions per second**, depending on transaction size and validator performance​.

***

## **How does the network handle congestion or high transaction volumes?**

The network handles congestion through:

* **Pending transactions and transaction lifetimes**, ensuring transactions that cannot be processed immediately wait in a queue instead of failing.
* **Transaction tips**, which allow users to prioritize their transactions by offering additional fees to validators.
* **Block producer selection based on transaction weight**, meaning heavier transactions may impact block time​.