Crate penumbra_storage

source ·
Expand description

Storage and management of chain state.

This crate provides a versioned, verifiable key-value store that also supports lightweight, copy-on-write snapshots and transactional semantics. The Storage type is a handle for an instance of a backing store, implemented using RocksDB. The storage records a sequence of versioned [State]s. The [State] type is a lightweight snapshot of a particular version of the chain state.

Each [State] instance can also be used as a copy-on-write fork to build up changes before committing them to persistent storage. The [StateTransaction] type collects a group of writes, which can then be applied to the (in-memory) [State] fork. Finally, the changes accumulated in the [State] instance can be committed to the persistent Storage.

Reads are performed with the StateRead trait, implemented by both [State] and [StateTransaction], and reflect any currently cached writes. Writes are performed with the StateWrite trait, which is only implemented for [StateTransaction].

The storage system provides two data stores:

  • A verifiable key-value store, with UTF-8 keys and byte values, backed by the Jellyfish Merkle Tree. The JMT is a sparse merkle tree that records hashed keys, so we also record an index of the keys themselves to allow range queries on keys rather than key hashes. This index, however, is not part of the verifiable consensus state.

  • A secondary, non-verifiable key-value store with byte keys and byte values, backed directly by RocksDB. This is intended for use building application-specific indexes of the verifiable consensus state.

While the primary key-value store records byte values, it is intended for use with Protobuf-encoded data. To this end, the StateRead and StateWrite traits have provided methods that use the [penumbra_proto::Protobuf] trait to automatically (de)serialize into proto or domain types, allowing its use as an object store.


  • Concrete futures types used by the storage crate.


  • A cache of changes to the state of the blockchain.
  • A wrapper type for a byte slice that implements Debug by escaping non-printable bytes.
  • A root of a JellyfishMerkleTree.
  • A snapshot of the underlying storage at a specific state version, suitable for read-only access by multiple threads, e.g., RPC calls.
  • An arbitrarily-deeply nested stack of delta updates to an underlying state.
  • A handle for a storage instance, backed by RocksDB.
  • A Storage instance backed by a tempfile::TempDir for testing.