A memory-mapped, append-only file used by AccountsDB to store account data. Each AppendVec corresponds to a specific slot and contains serialized account entries (pubkey, lamports, data, owner, etc.). AppendVecs are immutable once the slot is rooted, enabling efficient snapshotting and cleanup.
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A memory-mapped, append-only file used by AccountsDB to store account data. Each AppendVec corresponds to a specific slot and contains serialized account entries (pubkey, lamports, data, owner, etc.). AppendVecs are immutable once the slot is rooted, enabling efficient snapshotting and cleanup.
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Think of it as part of the chain machinery that keeps ordering, execution, or consensus moving.
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Consensus, leader rotation, slots, epochs, and the runtime.
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AppendVec (append-vec) Category: Core Protocol Definition: A memory-mapped, append-only file used by AccountsDB to store account data. Each AppendVec corresponds to a specific slot and contains serialized account entries (pubkey, lamports, data, owner, etc.). AppendVecs are immutable once the slot is rooted, enabling efficient snapshotting and cleanup. Related: AccountsDB
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The persistent storage layer for all Solana accounts. AccountsDB stores account data in memory-mapped AppendVec files, indexed by pubkey and slot. It supports fast lookups, handles account deduplication across slots, and periodically cleans up dead accounts. AccountsDB is the largest consumer of validator disk space.
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The persistent storage layer for all Solana accounts. AccountsDB stores account data in memory-mapped AppendVec files, indexed by pubkey and slot. It supports fast lookups, handles account deduplication across slots, and periodically cleans up dead accounts. AccountsDB is the largest consumer of validator disk space.
The Rust-based Solana validator client maintained by Anza (formerly Solana Labs). Agave is the original and most widely deployed validator implementation. It handles all aspects of validation: TPU, TVU, gossip, AccountsDB, and RPC. The name 'Agave' was adopted to distinguish it from the Firedancer client.
A next-generation consensus protocol proposed in SIMD-0326 that aims to collapse Solana's legacy systems (Proof of History, Tower BFT, gossip-based vote propagation) into two streamlined mechanisms: Rotor for data propagation and Votor for off-chain voting. Alpenglow targets reducing transaction finality from ~12.8 seconds to under 150 milliseconds, representing the most significant consensus overhaul in Solana's history.
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The persistent storage layer for all Solana accounts. AccountsDB stores account data in memory-mapped AppendVec files, indexed by pubkey and slot. It supports fast lookups, handles account deduplication across slots, and periodically cleans up dead accounts. AccountsDB is the largest consumer of validator disk space.
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A clock mechanism that cryptographically proves the passage of time between events. PoH uses a sequential SHA-256 hash chain where each output becomes the next input, creating a verifiable ordering of events without requiring consensus. The leader produces ~400,000 hashes per slot (~400ms), and any validator can verify the sequence in parallel, enabling Solana's high throughput by removing the need for validators to agree on time.
Solana's custom BFT consensus algorithm built on top of Proof of History. Tower BFT uses PoH as a clock to reduce communication overhead in traditional PBFT from O(n²) to O(n). Validators vote on forks with exponentially increasing lockout periods—each consecutive vote doubles the lockout, making rollbacks progressively more expensive. A fork is finalized when it reaches supermajority (66.7%+ of stake).
A time window during which a designated leader validator can produce a block. Each slot lasts approximately 400 milliseconds. Slots are numbered sequentially from genesis and grouped into epochs of 432,000 slots (~2-3 days). Not every slot produces a block—a skipped slot means the leader was offline or too slow.
A set of entries produced by a leader during a single slot. A block contains transactions bundled into entries, each with a PoH hash proving ordering. Blocks are broken into shreds for network propagation via Turbine. Maximum block size is limited by compute units (48M CU cap per block) rather than byte size.