Module persistence 

Persistence Layer

ACID guarantees

Database persistence is built around the ACID properties:

• Atomicity: operations either fully complete or fully roll back — no partial writes
• Consistency: the database always moves from one valid state to another
• Isolation: concurrent transactions don’t interfere with each other
• Durability: once a write is committed, it survives crashes and power loss

Write-Ahead Log (WAL)

The WAL is the standard technique for durability. The idea: write the operation to a sequential log file BEFORE modifying the actual data. If the process crashes mid-write, the log can be replayed on recovery to reconstruct the correct state. This same pattern is used by PostgreSQL, SQLite, and RocksDB internally.

RocksDB

RocksDB is Facebook’s embedded key-value store, evolved from Google’s LevelDB. It uses an LSM-tree (Log-Structured Merge-tree) architecture optimized for write-heavy workloads: writes go to an in-memory buffer (memtable), which periodically flushes to sorted disk files (SSTables) that are compacted in the background. Column families provide logical separation within a single database instance — each is an independent LSM-tree.

Multi-tenancy

Multiple isolated “tenants” share one database process. Each tenant gets its own RocksDB column family (like a namespace), ensuring data isolation. Resource quotas (max nodes, max edges, storage limits) prevent any single tenant from monopolizing shared resources.

PersistenceManager

The PersistenceManager orchestrates WAL + RocksDB + TenantManager. All writes flow through the WAL first (for durability), then to RocksDB (for indexed storage). On startup, any WAL entries written after the last checkpoint are replayed to bring the in-memory graph state up to date.

Re-exports

pub use storage::PersistentStorage;

pub use storage::StorageError;

pub use storage::StorageResult;

pub use tenant::AgentConfig;

pub use tenant::AutoEmbedConfig;

pub use tenant::LLMProvider;

pub use tenant::NLQConfig;

pub use tenant::ResourceQuotas;

pub use tenant::ResourceUsage;

pub use tenant::Tenant;

pub use tenant::TenantError;

pub use tenant::TenantManager;

pub use tenant::TenantResult;

pub use tenant::ToolConfig;

pub use wal::Wal;

pub use wal::WalEntry;

pub use wal::WalError;

pub use wal::WalResult;

Modules

storage

RocksDB Storage Layer

tenant

Multi-tenancy implementation with resource quotas

wal

Write-Ahead Log (WAL)

Structs

PersistenceManager

Integrated persistence manager combining WAL, storage, and tenancy

Enums

PersistenceError

Persistence errors

Type Aliases

PersistenceResult