Solana Alpenglow targets 150ms transaction finality

Solana activated its Alpenglow consensus upgrade on Oct. 21, targeting transaction finality in about 150 milliseconds instead of 12.8 seconds. The Solana Foundation’s upgrade page says it went live at the start of epoch 1064; The Block’s report says the change retires TowerBFT, which Solana had used since its March 2020 launch.

How does Alpenglow change transaction settlement?

Alpenglow lets validators send votes directly to one another and combine approvals into certificates, so a block can become final after one or two voting rounds. Under TowerBFT, validators recorded votes as transactions and approvals accumulated across successive blocks, according to Solana’s upgrade page.

Finality is the point at which an application can treat a transaction as settled. CoinDesk reports that the 150-millisecond figure is a target under normal network conditions, not a guarantee for every payment.

What changes for Solana users and apps?

Users can keep their existing wallets, and transaction fees and application operation remain unchanged, Solana says. Faster finality could let exchanges credit deposits sooner or merchants release goods after receiving a payment, though how quickly that appears to users also depends on the service handling it, CoinDesk reports.

Alpenglow changes consensus, not transaction execution: the Solana Virtual Machine, transactions, programs and fees stay the same, according to the Foundation. Validators now exchange votes directly rather than putting vote transactions on-chain.

That shift may make network dashboards show fewer transactions because validator votes no longer count in block totals. The Foundation says this is an accounting change; comparisons with earlier activity need to distinguish user transactions from validator votes.

Sources

• Solana Foundation’s upgrade page — solana.com
• The Block’s report — theblock.co