Package org.apache.druid.segment

Interface DimensionMergerV9

All Superinterfaces:

DimensionMerger

All Known Implementing Classes:

AutoTypeColumnMerger, DictionaryEncodedColumnMerger, DoubleDimensionMergerV9, FloatDimensionMergerV9, LongDimensionMergerV9, NumericDimensionMergerV9, StringDimensionMergerV9

public interface DimensionMergerV9
extends DimensionMerger

Processing related interface DimensionMerger subclass to be used with IndexMergerV9.

Method Summary

Modifier and Type	Method	Description
default void	attachParent(DimensionMergerV9 parent, List<IndexableAdapter> projectionAdapters)	Attaches the DimensionMergerV9 of a "projection" parent column so that stuff like value dictionaries can be shared between parent and child.
ColumnDescriptor	makeColumnDescriptor()	Return a ColumnDescriptor containing ColumnPartSerde objects appropriate for this DimensionMerger's value metadata, sequence of row values, and index structures.
default void	markAsParent()	Sets this merger as the "parent" of another merger for a "projection", allowing for this merger to preserve any state which might be required for the projection mergers to do their thing.

Methods inherited from interface org.apache.druid.segment.DimensionMerger

convertSortedSegmentRowValuesToMergedRowValues, hasOnlyNulls, processMergedRow, writeIndexes, writeMergedValueDictionary

Method Details

makeColumnDescriptor

ColumnDescriptor makeColumnDescriptor()

Return a ColumnDescriptor containing ColumnPartSerde objects appropriate for this DimensionMerger's value metadata, sequence of row values, and index structures.

Returns:

ColumnDescriptor that IndexMergerV9 will use to build a column.

markAsParent

default void markAsParent()

Sets this merger as the "parent" of another merger for a "projection", allowing for this merger to preserve any state which might be required for the projection mergers to do their thing. This method MUST be called prior to performing any merge work. Typically, this method is only implemented if attachParent(DimensionMergerV9, List) requires it.

attachParent

default void attachParent(DimensionMergerV9 parent,
 List<IndexableAdapter> projectionAdapters)
                   throws IOException

Attaches the DimensionMergerV9 of a "projection" parent column so that stuff like value dictionaries can be shared between parent and child. This method is called during merging instead of DimensionMerger.writeMergedValueDictionary(List) if the parent column exists.

Throws:

IOException

See Also:

• IndexMergerBase.makeProjections(org.apache.druid.segment.file.SegmentFileBuilder, java.util.List<org.apache.druid.segment.AggregateProjectionMetadata>, java.util.List<org.apache.druid.segment.IndexableAdapter>, org.apache.druid.segment.IndexSpec, org.apache.druid.segment.writeout.SegmentWriteOutMedium, org.apache.druid.segment.ProgressIndicator, java.io.File, org.apache.druid.java.util.common.io.Closer, java.util.Map<java.lang.String, org.apache.druid.segment.DimensionMergerV9>, org.apache.druid.segment.Metadata)