Struct datafusion::physical_optimizer::dist_enforcement::EnforceDistribution

pub struct EnforceDistribution {}

The EnforceDistribution rule ensures that distribution requirements are met in the strictest way. It might add additional RepartitionExec to the plan tree and give a non-optimal plan, but it can avoid the possible data skew in joins.

For example for a HashJoin with keys(a, b, c), the required Distribution(a, b, c) can be satisfied by several alternative partitioning ways: [(a, b, c), (a, b), (a, c), (b, c), (a), (b), (c), ( )].

This rule only chooses the exactly match and satisfies the Distribution(a, b, c) by a HashPartition(a, b, c).

Implementations

impl EnforceDistribution

pub fn new() -> Self

Trait Implementations

impl Default for EnforceDistribution

fn default() -> EnforceDistribution

Returns the “default value” for a type.

impl PhysicalOptimizerRule for EnforceDistribution

fn optimize( &self, plan: Arc<dyn ExecutionPlan>, config: &ConfigOptions ) -> Result<Arc<dyn ExecutionPlan>>

Rewrite plan to an optimized form

fn name(&self) -> &str

A human readable name for this optimizer rule

fn schema_check(&self) -> bool

A flag to indicate whether the physical planner should valid the rule will not change the schema of the plan after the rewriting. Some of the optimization rules might change the nullable properties of the schema and should disable the schema check.