Crate relational_engine 

SQL-like relational engine with SIMD-accelerated filtering.

Provides table storage, indexing, and query execution on top of tensor_store::RelationalSlab for columnar storage.

Durability Model

When using durable storage (via RelationalEngine::open_durable or RelationalEngine::recover), the following data is persisted:

Persisted and auto-recovered:

• Table schemas and metadata
• Row data (columnar storage)
• B-tree indexes (automatically rebuilt on recovery)
• Row counters (automatically rebuilt from scanning data)

NOT persisted (must recreate after recovery):

• Hash indexes: call RelationalEngine::create_index after recovery
• Transaction state: transactions are aborted on crash

Recovery Example

// Open durable engine - B-tree indexes are automatically rebuilt
let engine = RelationalEngine::recover(
    "data/wal",
    &WalConfig::default(),
    Some(Path::new("data/snapshot")),
)?;

// Only hash indexes need to be recreated after recovery
for table in engine.list_tables() {
    engine.create_index(&table, "user_id")?;
    // B-tree indexes are already restored!
}

Re-exports

pub use transaction::Transaction;

pub use transaction::TransactionManager;

pub use transaction::TxPhase;

pub use cursor::CursorBuilder;

pub use cursor::StreamingCursor;

pub use observability::IndexMissReport;

pub use observability::IndexTracker;

pub use observability::QueryMetrics;

Modules

cursor

Streaming cursor API for memory-efficient large result sets.

observability

Observability infrastructure for relational engine.

transaction

Transaction support for RelationalEngine.

Structs

Column

Column definition with name, type, and nullability.

ColumnData

Column data with values and null tracking.

ColumnarScanOptions

Options for columnar scan operations.

CursorOptions

Options for cursor-based iteration over query results.

ForeignKeyConstraint

Foreign key constraint definition.

GroupedRow

Result of a grouped aggregate query.

QueryOptions

Options for query execution.

RelationalConfig

Configuration for RelationalEngine resource limits and timeouts.

RelationalEngine

SQL-like relational database engine.

Row

A row with ID and column values.

RowCursor

Iterator over query results.

Schema

Table schema defining column structure.

WalConfig

WAL configuration.

Enums

AggregateExpr

Aggregate expression for GROUP BY queries.

AggregateRef

Reference to an aggregate in HAVING clause.

AggregateValue

Typed aggregate result value.

ColumnType

Column data type.

Condition

Query filter condition.

Constraint

Table constraint definition.

HavingCondition

HAVING condition for filtering groups after aggregation.

ReferentialAction

Referential action for foreign key constraints.

RelationalError

Errors from relational engine operations.

Value

Query value type.

Type Aliases

Result

Result type alias for relational engine operations.