Polkadot/Substrate PoC-2

The second in the series of Polkadot/Substrate proofs-of-concept. It is released after a 10-day period of stabilisation for the new libp2p based peer network and the introduction of the new runtime onto the network.

Features

The new state-transition function improves the staking system and its incentivisation alignment with slashing and nomination. It introduces parachains allowing for co-finalisation of independent chains. PoC-2's runtime introduces account-enumeration and with it we have "tiny" index addresses, allowing for very small 1 and 2 byte address formats, allowing for 4-6 character addresses (e.g. "5Gxu", "5James") and a steep reduction in transaction (read: block) size.

It also introduces a new comprehensive fee structure for transactions, existential deposits (or "minimum account balances") to ensure dust accounts never exist and automatic account reaping (deleting unused accounts). Balances are now 128-bit values rather than 64-bit for PoC-1.

Regarding the client, this release introduces various improvements and optimisations in Substrate including semantic runtime versioning, interpreter speedups and wasm/native consensus comparison. There is now pruning in the state trie DB, reducing database size.

Telemetry (remote reporting of block number &c) is enabled by default when running on the testnet (now renamed to Krumme Lanke). To turn it off, use --no-telemetry. Chains can be exported and imported on the CLI now, and JSON & genesis can be imported/exported.

Known issues

Slow resource leakage has been observed, leading to increased RAM and CPU usage over time. At present we see around 0.5GB/day leaked under certain circumstances. If it becomes a problem, a restart is a sound workaround. We aim to make a point release in this series once these issues have been addressed properly.