Module optimizer 

Query optimizer traits and infrastructure for Krishiv.

This crate defines the rule-based optimizer framework used by both the logical and physical planning pipelines, as well as the AQE (Adaptive Query Execution) extension traits that operate on runtime statistics collected during stage execution.

Structs

AqeOptimizer

AQE optimizer that automatically skips partition-changing rules for streaming plans.

AutoPartitionRule

AQE rule that adjusts the bucket count of Hash and RoundRobin exchange nodes based on the observed data volume from the previous execution.

BroadcastAutoRule

Logical optimizer rule that marks small scan nodes as broadcast-eligible.

BroadcastRuntimeRule

AQE rule that promotes or demotes broadcast joins based on the observed output size from the previous execution.

CboCostModel

NDV-aware cost model.

CoalesceAdvice

Advice returned by the coalesce rule: which partition indices should be merged.

CoalesceRule

Merges partitions whose memory_bytes falls below min_partition_bytes.

ColumnCboStats

Per-column statistics collected by ANALYZE TABLE … FOR COLUMNS.

ConstantFoldingRule

Optimizer rule that folds constant sub-expressions inside filter predicates and removes always-true / always-false filters.

Cost

Estimated cost of executing a plan.

DppAdvice

Advice produced by the DPP rule: the join keys and the build-side side of the join (the small side whose distinct values feed the filter).

DynamicPartitionPruningRule

AQE rule that injects a runtime filter on the probe side of a star-schema join, sourced from the build side’s distinct values.

FileStats

Per-file metadata used by SmallFilePlanner.

JoinReorderRule

Logical optimizer rule that puts the smaller table on the left of commutative joins.

OptimizeResult

The result of running the optimizer over a logical plan.

Optimizer

Rule-based optimizer for Krishiv logical plans.

PredicatePushdownRule

Push Filter predicates down into TableScan nodes.

RuntimeStats

Runtime statistics collected by an executor stage.

SkewAdvice

Advice returned by the skew-join rule: which partition indices should be split and what salting factor to use.

SkewJoinRule

AQE rule that splits hot partitions of a HashJoin’s probe side using salting, and replicates the build side accordingly.

SmallFilePlanner

Plans scan parallelism for a set of files.

SplitPlanAdvice

Advice produced by SmallFilePlanner: a list of scan groups where each group of file paths should be handled by a single executor task.

StaticCostModel

Static, row-count-aware cost model for logical plans.

StreamingAqeGuard

Guards streaming plans from AQE rules that would change partition count.

TableCboStats

Catalog statistics the cost model needs for one table.

TableStatsRegistry

ThresholdSkewRule

Detects hot partitions whose input_rows exceeds threshold × median_rows.

Enums

OptimizerError

Errors produced while validating or executing optimizer rules.

Constants

DEFAULT_BROADCAST_THRESHOLD_ROWS

Default threshold for auto-broadcast: tables with estimated rows below this value are candidates for broadcast join. ~1M rows ≈ 100 MiB at 100 bytes/row.

DEFAULT_MAX_BROADCAST_BYTES

Default maximum observed output size for runtime broadcast promotion: 64 MiB.

DEFAULT_SALT_FACTOR

Default salting factor when a hot partition is detected.

DEFAULT_SKEW_THRESHOLD

Default median-multiplier threshold (1 + the relative overshoot).

DPP_MAX_BUILD_ROWS

Maximum number of build-side rows after which DPP is no longer worth the cost of building, serialising, and pushing the filter.

DPP_MAX_KEYS

Maximum number of distinct keys the filter retains.

Traits

AqeRule

An Adaptive Query Execution rule that re-plans based on RuntimeStats.

CostModel

Estimates the cost of executing a LogicalPlan.

OptimizerRule

A rule that transforms a LogicalPlan into a (possibly better) one.

SkewRule

A rule that detects skewed (hot) partitions from RuntimeStats.

Functions

default_aqe_optimizer

Default AQE optimizer with guarded coalescing and the streaming guard.

default_aqe_optimizer_with_parallelism

default_aqe_optimizer whose coalescing will not drop a stage below min_partitions partitions.

default_aqe_optimizer_with_stats

default_aqe_optimizer backed by the process-global table statistics registry (Phase 54): cold-start estimates use CboCostModel over stats collected by ANALYZE TABLE / Iceberg auto-stats instead of the static per-operator coefficients.

default_aqe_optimizer_with_stats_and_parallelism

default_aqe_optimizer_with_stats with a coalescing parallelism floor.

default_logical_optimizer

global_table_stats

Process-global table statistics registry (Phase 54).

Type Aliases

OptimizerResult

Result type for logical and adaptive optimizer pipelines.