io.delta.standalone

Interface DeltaScan

public interface DeltaScan

Provides access to an iterator over the files in this snapshot.

Typically created with a read predicate Expression to let users filter files. Please note filtering is only supported on partition columns and users should use getResidualPredicate() to check for any unapplied portion of the input predicate.

Method Summary

Modifier and Type	Method and Description
CloseableIterator<AddFile>	getFiles() Creates a CloseableIterator over files belonging to this snapshot.
java.util.Optional<Expression>	getInputPredicate()
java.util.Optional<Expression>	getPushedPredicate()
java.util.Optional<Expression>	getResidualPredicate()

Method Detail

getFiles

CloseableIterator<AddFile> getFiles()

Creates a CloseableIterator over files belonging to this snapshot.

There is no iteration ordering guarantee among files.

Files returned are guaranteed to satisfy the predicate, if any, returned by getPushedPredicate().

Returns:

a CloseableIterator over the files in this snapshot that satisfy getPushedPredicate()

getInputPredicate

java.util.Optional<Expression> getInputPredicate()

Returns:

the input predicate passed in by the user

getPushedPredicate

java.util.Optional<Expression> getPushedPredicate()

Returns:

portion of the input predicate that can be evaluated by Delta Standalone using only metadata (filters on partition columns). Files returned by getFiles() are guaranteed to satisfy the pushed predicate, and the caller doesn’t need to apply them again on the returned files.

getResidualPredicate

java.util.Optional<Expression> getResidualPredicate()

Returns:

portion of the input predicate that may not be fully applied. Files returned by getFiles() are not guaranteed to satisfy the residual predicate, and the caller should still apply them on the returned files.