Struct datafusion_physical_plan::union::UnionExec

pub struct UnionExec { /* private fields */ }

UnionExec: UNION ALL execution plan.

UnionExec combines multiple inputs with the same schema by concatenating the partitions. It does not mix or copy data within or across partitions. Thus if the input partitions are sorted, the output partitions of the union are also sorted.

For example, given a UnionExec of two inputs, with N partitions, and M partitions, there will be N+M output partitions. The first N output partitions are from Input 1 partitions, and then next M output partitions are from Input 2.

                      ▲       ▲           ▲         ▲
                      │       │           │         │
    Output            │  ...  │           │         │
  Partitions          │0      │N-1        │ N       │N+M-1
(passes through   ┌────┴───────┴───────────┴─────────┴───┐
the N+M input    │              UnionExec               │
 partitions)     │                                      │
                 └──────────────────────────────────────┘
                                     ▲
                                     │
                                     │
      Input           ┌────────┬─────┴────┬──────────┐
    Partitions        │ ...    │          │     ...  │
                   0  │        │ N-1      │ 0        │  M-1
                 ┌────┴────────┴───┐  ┌───┴──────────┴───┐
                 │                 │  │                  │
                 │                 │  │                  │
                 │                 │  │                  │
                 │                 │  │                  │
                 │                 │  │                  │
                 │                 │  │                  │
                 │Input 1          │  │Input 2           │
                 └─────────────────┘  └──────────────────┘

Implementations

impl UnionExec

pub fn new(inputs: Vec<Arc<dyn ExecutionPlan>>) -> Self

Create a new UnionExec

pub fn inputs(&self) -> &Vec<Arc<dyn ExecutionPlan>>

Get inputs of the execution plan

Trait Implementations

impl Debug for UnionExec

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

Formats the value using the given formatter.

impl DisplayAs for UnionExec

fn fmt_as(&self, t: DisplayFormatType, f: &mut Formatter<'_>) -> Result

Format according to DisplayFormatType, used when verbose representation looks different from the default one

impl ExecutionPlan for UnionExec

fn as_any(&self) -> &dyn Any

Return a reference to Any that can be used for downcasting

fn unbounded_output(&self, children: &[bool]) -> Result<bool>

Specifies whether this plan generates an infinite stream of records. If the plan does not support pipelining, but its input(s) are infinite, returns an error to indicate this.

fn output_partitioning(&self) -> Partitioning

Output of the union is the combination of all output partitions of the inputs

fn schema(&self) -> SchemaRef

Get the schema for this execution plan

fn children(&self) -> Vec<Arc<dyn ExecutionPlan>>

Get a list of children ExecutionPlans that act as inputs to this plan. The returned list will be empty for leaf nodes such as scans, will contain a single value for unary nodes, or two values for binary nodes (such as joins).

fn output_ordering(&self) -> Option<&[PhysicalSortExpr]>

If the output of this ExecutionPlan within each partition is sorted, returns Some(keys) with the description of how it was sorted.

fn maintains_input_order(&self) -> Vec<bool>

Returns false if this ExecutionPlan’s implementation may reorder rows within or between partitions.

fn equivalence_properties(&self) -> EquivalenceProperties

Get the EquivalenceProperties within the plan.

fn with_new_children( self: Arc<Self>, children: Vec<Arc<dyn ExecutionPlan>> ) -> Result<Arc<dyn ExecutionPlan>>

Returns a new ExecutionPlan where all existing children were replaced by the children, oi order

fn execute( &self, partition: usize, context: Arc<TaskContext> ) -> Result<SendableRecordBatchStream>

Begin execution of partition, returning a Stream of RecordBatches.

fn metrics(&self) -> Option<MetricsSet>

Return a snapshot of the set of Metrics for this ExecutionPlan. If no Metrics are available, return None.

fn statistics(&self) -> Result<Statistics>

Returns statistics for this ExecutionPlan node. If statistics are not available, should return Statistics::new_unknown (the default), not an error.

fn benefits_from_input_partitioning(&self) -> Vec<bool>

Specifies whether the ExecutionPlan benefits from increased parallelization at its input for each child.

fn required_input_distribution(&self) -> Vec<Distribution>

Specifies the data distribution requirements for all the children for this ExecutionPlan, By default it’s [Distribution::UnspecifiedDistribution] for each child,

fn required_input_ordering(&self) -> Vec<Option<Vec<PhysicalSortRequirement>>>

Specifies the ordering required for all of the children of this ExecutionPlan.

fn repartitioned( &self, _target_partitions: usize, _config: &ConfigOptions ) -> Result<Option<Arc<dyn ExecutionPlan>>>

If supported, attempt to increase the partitioning of this ExecutionPlan to produce target_partitions partitions.