Garant from Stellar Development Foundation presents Protocol 23 (WISC) performance enhancements for smart contracts, including parallel transaction execution via conflict-free parallelism, in-memory state caching, and reusable module caching that reduce instruction costs by up to 80% and improve network throughput.
Garant, a core engineer at Stellar Development Foundation, discusses Protocol 23 (WISC), the largest smart contract protocol upgrade since launch. Three major performance features shipped: parallel transaction execution (CAP 63) enabling multiple transactions to execute simultaneously via conflict-free parallelism; in-memory state (CAP 62, 66) eliminating disk reads for smart contract invocations and removing read fees; and reusable module cache (CAP 65) removing expensive WASM parsing costs by caching instantiated modules. The presentation covers how conflict-free parallelism works by clustering transactions with read-write conflicts into the same execution lane, preventing concurrent conflicts. Garant explains why Stellar uses rent and protocol-level caching instead of optimistic approaches used by other chains, drawing lessons from the 2016 Ethereum Shanghai attack. Results show instruction costs reduced up to 80%, rent fees down 10x, and single-thread SAC payment throughput reaching 4,200 per second with potential for 12,000 per second with 32 threads. Validator requirements remain unchanged in the short term.