Struct AdaptiveQueryPlan 

pub struct AdaptiveQueryPlan {
    pub patterns: Vec<TriplePattern>,
    pub estimated_costs: Vec<PatternCost>,
    pub reorder_threshold: u64,
    /* private fields */
}

A query plan that can reorder its triple patterns at runtime based on observed intermediate result sizes.

The plan starts with an optimized static ordering produced by JoinOrderOptimizer, then checks after each pattern execution whether the actual cardinality diverges enough from the estimate to warrant re-ordering the remaining patterns.

Fields

patterns: Vec<TriplePattern>

Current ordered list of triple patterns.

estimated_costs: Vec<PatternCost>

Pre-computed cost estimates (same order as patterns).

reorder_threshold: u64

How much actual cardinality must differ from estimate (as a ratio) before we trigger a re-order. Default: 5.0 (5×).

Implementations

impl AdaptiveQueryPlan

pub fn new(patterns: Vec<TriplePattern>, stats: &JoinGraphStats) -> Self

Create a plan from a slice of patterns, immediately optimizing their order.

pub fn with_reorder_threshold(self, threshold: u64) -> Self

Set the reorder threshold ratio (actual / expected must exceed this).

pub fn should_reorder( &self, actual_cardinality: u64, pattern_idx: usize, ) -> bool

Check whether the observed actual cardinality for pattern_idx is far enough from the estimate to justify reordering remaining patterns.

pub fn reorder_from(&mut self, pattern_idx: usize, stats: &JoinGraphStats)

Reorder the remaining patterns (starting at pattern_idx) given updated stats derived from observed intermediate results.

pub fn next_pattern(&mut self) -> Option<&TriplePattern>

Advance the plan to the next pattern. Returns the next pattern or None if the plan is exhausted.

pub fn reset(&mut self)

Reset execution cursor to the beginning.

pub fn remaining(&self) -> usize

Number of patterns remaining (not yet executed).

pub fn elapsed(&self) -> Duration

Elapsed time since plan creation.

pub fn len(&self) -> usize

Total number of patterns in the plan.

pub fn is_empty(&self) -> bool

Whether the plan has no patterns.

Trait Implementations

impl Clone for AdaptiveQueryPlan

fn clone(&self) -> AdaptiveQueryPlan

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AdaptiveQueryPlan

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

Formats the value using the given formatter.