RegionScanner

store_api::region_engine

Trait RegionScanner 

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pub trait RegionScanner:
    Debug
    + DisplayAs
    + Send {
    // Required methods
    fn name(&self) -> &str;
    fn properties(&self) -> &ScannerProperties;
    fn schema(&self) -> SchemaRef;
    fn metadata(&self) -> RegionMetadataRef;
    fn prepare(&mut self, request: PrepareRequest) -> Result<(), BoxedError>;
    fn scan_partition(
        &self,
        ctx: &QueryScanContext,
        metrics_set: &ExecutionPlanMetricsSet,
        partition: usize,
    ) -> Result<SendableRecordBatchStream, BoxedError>;
    fn has_predicate_without_region(&self) -> bool;
    fn add_dyn_filter_to_predicate(
        &mut self,
        filter_exprs: Vec<Arc<dyn PhysicalExpr>>,
    ) -> Vec<bool>;
    fn set_logical_region(&mut self, logical_region: bool);
}
Expand description

A scanner that provides a way to scan the region concurrently.

The scanner splits the region into partitions so that each partition can be scanned concurrently. You can use this trait to implement an ExecutionPlan.

Required Methods§

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fn name(&self) -> &str

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fn properties(&self) -> &ScannerProperties

Returns the properties of the scanner.

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fn schema(&self) -> SchemaRef

Returns the schema of the record batches.

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fn metadata(&self) -> RegionMetadataRef

Returns the metadata of the region.

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fn prepare(&mut self, request: PrepareRequest) -> Result<(), BoxedError>

Prepares the scanner with the given partition ranges.

This method is for the planner to adjust the scanner’s behavior based on the partition ranges.

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fn scan_partition( &self, ctx: &QueryScanContext, metrics_set: &ExecutionPlanMetricsSet, partition: usize, ) -> Result<SendableRecordBatchStream, BoxedError>

Scans the partition and returns a stream of record batches.

§Panics

Panics if the partition is out of bound.

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fn has_predicate_without_region(&self) -> bool

Check if there is any predicate exclude region partition exprs that may be executed in this scanner.

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fn add_dyn_filter_to_predicate( &mut self, filter_exprs: Vec<Arc<dyn PhysicalExpr>>, ) -> Vec<bool>

Add the given dynamic filter expressions to the predicate of the scanner. Returns a vector of booleans indicating which filter expressions were applied. true indicates the filter expression was applied(will be use by scanner to prune by stat for row group), false otherwise.

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fn set_logical_region(&mut self, logical_region: bool)

Sets whether the scanner is reading a logical region.

Implementors§