Struct transform::Optimizer

pub struct Optimizer {
    pub transforms: Vec<Box<dyn Transform>>,
}

A naive optimizer for relation expressions.

The optimizer currently applies only peep-hole optimizations, from a limited set that were sufficient to get some of TPC-H up and working. It is worth a review at some point to improve the quality, coverage, and architecture of the optimizations.

Fields

transforms: Vec<Box<dyn Transform>>

The list of transforms to apply to an input relation.

Implementations

impl Optimizer

pub fn logical_optimizer() -> Self

Builds a logical optimizer that only performs logical transformations.

pub fn physical_optimizer() -> Self

Builds a physical optimizer.

Performs logical transformations followed by all physical ones. This is meant to be used for optimizing each view within a dataflow once view inlining has already happened, right before dataflow rendering.

pub fn logical_cleanup_pass() -> Self

Contains the logical optimizations that should run after cross-view transformations run.

pub fn optimize(
    &mut self,
    relation: MirRelationExpr
) -> Result<OptimizedMirRelationExpr, TransformError>

Optimizes the supplied relation expression.

These optimizations are performed with no information about available arrangements, which makes them suitable for pre-optimization before dataflow deployment.

pub(crate) fn transform(
    &self,
    relation: &mut MirRelationExpr,
    indexes: &HashMap<GlobalId, Vec<(GlobalId, Vec<MirScalarExpr>)>>
) -> Result<(), TransformError>

Optimizes the supplied relation expression in place, using available arrangements.

This method should only be called with non-empty indexes when optimizing a dataflow, as the optimizations may lock in the use of arrangements that may cease to exist.

Trait Implementations

impl Debug for Optimizer

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

Formats the value using the given formatter.