Struct JoinReorder 

pub struct JoinReorder {
    pub model: Arc<CostModel>,
    pub dp_threshold: usize,
}

Cost-based join reordering pass.

Uses DPccp (bottom-up DP over connected subsets) for ≤ dp_threshold atoms and GOO (greedy ordering optimisation) above that threshold.

Fields

model: Arc<CostModel>

The cost model used to estimate scan and join costs.

dp_threshold: usize

Maximum number of atoms for the DPccp algorithm; above this, GOO is used.

Implementations

impl JoinReorder

pub fn new(model: Arc<CostModel>) -> Self

Create a new JoinReorder pass with the default DP threshold of 12.

pub fn with_threshold(model: Arc<CostModel>, dp_threshold: usize) -> Self

Create a JoinReorder pass with an explicit DP threshold.

Trait Implementations

impl OptPass for JoinReorder

fn name(&self) -> &'static str

Short name identifying this pass (for tracing / debugging).

fn apply(&self, plan: LogicalPlan) -> LogicalPlan

Apply the rewrite to plan, returning the (possibly modified) plan.