Feature Gate: Accounts Lt Hash

[brooksprumo]

SIMD

solana-foundation/solana-improvement-documents#215

Description

The accounts lt hash is a lattice-based hash of all the accounts. This is an accumulator-style hash of the total account state that can be updated incrementally for each block. The accounts lt hash will enable us to remove the merkle-based accounts hash calculations.

This feature gate does the following:

• Mixes in the accounts lt hash into the bank hash
• Removes the Epoch Accounts Hash from the bank hash (and removes its calculation)
• At feature activation, calculate the accounts lt hash (unless already calculated)
• At startup, calculate the accounts lt hash (unless already got it from the snapshot)

The accounts lt hash is stored in each bank. During bank freeze, its value is updated.

Feature ID

LtHaSHHsUge7EWTPVrmpuexKz6uVHZXZL6cgJa7W7Zn

Activation Method

Single Core Contributor

Deployment Considerations

All clients (Agave, Firedancer, etc) must have this feature implemented before activation. Client-agnostic test vectors will be helpful here.

Partitioned Epoch Rewards should also be activated before this feature is activated. (now activated on all clusters)

Minimum Beta Version

No response

Minimum Stable Version

No response

Testnet Activation Epoch

No response

Devnet Activation Epoch

No response

Mainnet-Beta Activation Epoch

No response