Package io.delta.kernel.internal

Class ScanImpl

Object

io.delta.kernel.internal.ScanImpl

All Implemented Interfaces:

Scan

public class ScanImpl
extends Object
implements Scan

Implementation of Scan

Constructor Summary

Constructors

Constructor	Description
ScanImpl(StructType snapshotSchema, StructType readSchema, Protocol protocol, Metadata metadata, LogReplay logReplay, Optional<Predicate> filter, Path dataPath, SnapshotReport snapshotReport)

Method Summary

Modifier and Type	Method	Description
Optional<Predicate>	getRemainingFilter()	Get the remaining filter that is not guaranteed to be satisfied for the data Delta Kernel returns.
CloseableIterator<FilteredColumnarBatch>	getScanFiles(Engine engine)	Get an iterator of data files in this version of scan that survived the predicate pruning.
CloseableIterator<FilteredColumnarBatch>	getScanFiles(Engine engine, boolean includeStats)	Get an iterator of data files in this version of scan that survived the predicate pruning.
Row	getScanState(Engine engine)	Get the scan state associated with the current scan.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ScanImpl

public ScanImpl(StructType snapshotSchema,
 StructType readSchema,
 Protocol protocol,
 Metadata metadata,
 LogReplay logReplay,
 Optional<Predicate> filter,
 Path dataPath,
 SnapshotReport snapshotReport)

Method Details

getScanFiles

public CloseableIterator<FilteredColumnarBatch> getScanFiles(Engine engine)

Get an iterator of data files in this version of scan that survived the predicate pruning.

Specified by:

getScanFiles in interface Scan

Parameters:

engine - Engine instance to use in Delta Kernel.

Returns:

data in ColumnarBatch batch format. Each row correspond to one survived file.

See Also:

getScanFiles

public CloseableIterator<FilteredColumnarBatch> getScanFiles(Engine engine,
 boolean includeStats)

Get an iterator of data files in this version of scan that survived the predicate pruning.

When includeStats=true the JSON file statistics are always read from the log and included in the returned columnar batches which have schema InternalScanFileUtils.SCAN_FILE_SCHEMA_WITH_STATS. When includeStats=false the JSON file statistics may or may not be present in the returned columnar batches.

Parameters:

engine - the Engine instance to use

includeStats - whether to read and include the JSON statistics

Returns:

the surviving scan files as FilteredColumnarBatchs

getScanState

public Row getScanState(Engine engine)

Description copied from interface: Scan

Get the scan state associated with the current scan. This state is common across all files in the scan to be read.

Specified by:

getScanState in interface Scan

Parameters:

engine - Engine instance to use in Delta Kernel.

Returns:

Scan state in Row format.

getRemainingFilter

public Optional<Predicate> getRemainingFilter()

Description copied from interface: Scan

Get the remaining filter that is not guaranteed to be satisfied for the data Delta Kernel returns. This filter is used by Delta Kernel to do data skipping when possible.

Specified by:

getRemainingFilter in interface Scan

Returns:

the remaining filter as a Predicate.