Struct QueryContext 

pub struct QueryContext {
    pub limits: QueryLimits,
    /* private fields */
}

Query execution context with guard-rail tracking (EPIC-048).

Fields

limits: QueryLimits

Query limits configuration.

Implementations

impl QueryContext

pub fn new(limits: QueryLimits) -> Self

Creates a new query context with the given limits.

pub fn check_timeout(&self) -> Result<(), GuardRailViolation>

Checks if the query has timed out (US-001).

Errors

Returns GuardRailViolation::Timeout when elapsed time exceeds the configured timeout.

pub fn check_depth(&self, depth: u32) -> Result<(), GuardRailViolation>

Checks and updates traversal depth (US-002).

Errors

Returns GuardRailViolation::DepthExceeded when depth is greater than the configured maximum.

pub fn check_cardinality(&self, count: usize) -> Result<(), GuardRailViolation>

Checks and updates cardinality (US-003).

Errors

Returns GuardRailViolation::CardinalityExceeded when cumulative intermediate result count exceeds the configured maximum.

Known Limitation

This method is called on the final result set (post-filter, post-ORDER BY, pre-LIMIT). It does not track intermediate over-fetched candidate sets (e.g., candidates_k = execution_limit * 10 * N during similarity search). Those are bounded by MAX_LIMIT internally and therefore do not escape. Future work: thread QueryContext into ANN search to track intermediates.

pub fn check_memory(&self, bytes: usize) -> Result<(), GuardRailViolation>

Checks and updates memory usage (US-004).

Errors

Returns GuardRailViolation::MemoryExceeded when cumulative estimated memory usage exceeds the configured budget.

pub fn elapsed(&self) -> Duration

Returns elapsed time since query start.

pub fn memory_used(&self) -> usize

Returns current memory usage estimate.

pub fn add_traversal(&self, nodes_visited: u64, edges_traversed: u64)

Accumulates graph-traversal counters measured during MATCH execution.

Uses fetch_add so multiple traversal phases compose: a multi-pattern MATCH, and the GraphFirst + VectorFirst legs of the Parallel strategy, each add their own counts. Read back by EXPLAIN ANALYZE.

pub fn traversal_nodes_visited(&self) -> u64

Returns graph nodes visited during MATCH traversal (0 if no traversal ran).

pub fn traversal_edges_traversed(&self) -> u64

Returns graph edges traversed during MATCH traversal (0 if no traversal ran).

Trait Implementations

impl Debug for QueryContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.