nodedb-wal 0.2.1

Deterministic O_DIRECT write-ahead log with io_uring group commit
Documentation 
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// SPDX-License-Identifier: BUSL-1.1

//! # nodedb-wal
//!
//! Deterministic, O_DIRECT write-ahead log with group commit.
//!
//! This crate bypasses the Linux page cache entirely. Every WAL write goes
//! directly to NVMe via `O_DIRECT` (and eventually `io_uring`). This is
//! non-negotiable: if AI agents dump 10 GB of telemetry logs, the OS must NOT
//! evict hot HNSW vector indexes from RAM to cache WAL pages.
//!
//! ## Design
//!
//! - **O_DIRECT**: All writes bypass the page cache. Aligned to 4 KiB.
//! - **Group commit**: Thousands of concurrent writes are batched into a single
//!   `fsync`, maximizing NVMe IOPS.
//! - **CRC32C**: Every record has a checksum for silent bit-rot detection.
//! - **Deterministic replay**: WAL replay is idempotent — crash at any point,
//!   recover to a consistent prefix.
//!
//! ## Validation target
//!
//! Sustain 100,000+ async writes/sec with sub-millisecond p99 latency.
//! `free -m` cached memory must not move during the benchmark.

pub mod align;
pub mod crypto;
pub mod double_write;
pub mod error;
pub mod group_commit;
pub mod lazy_reader;
pub mod mmap_reader;
pub mod preamble;
pub mod reader;
pub mod record;
pub mod recovery;
pub mod replay;
pub mod secure_mem;
pub mod segment;
pub mod segmented;
pub mod temporal_purge;
pub mod tombstone;
#[cfg(feature = "io-uring")]
pub mod uring_writer;
pub mod writer;

pub use double_write::{DoubleWriteBuffer, DwbMode, wal_dwb_bytes_written_total};
pub use error::{Result, WalError};
pub use group_commit::GroupCommitter;
pub use lazy_reader::LazyWalReader;
pub use preamble::{
    CIPHER_AES_256_GCM, PREAMBLE_SIZE, PREAMBLE_VERSION, SEG_PREAMBLE_MAGIC, SegmentPreamble,
    WAL_PREAMBLE_MAGIC,
};
pub use record::{CalvinAppliedPayload, RecordHeader, RecordType, WalRecord};
pub use recovery::{RecoveryInfo, recover};
pub use replay::{TombstoneSet, extract_tombstones};
pub use secure_mem::SecureKey;
pub use segmented::{SegmentedWal, SegmentedWalConfig};
pub use temporal_purge::{TemporalPurgeEngine, TemporalPurgePayload};
pub use tombstone::{CollectionTombstonePayload, MAX_COLLECTION_NAME_LEN};
pub use writer::WalWriter;