Package org.apache.druid.segment

Class RowBasedStorageAdapter<RowType>

java.lang.Object

org.apache.druid.segment.RowBasedStorageAdapter<RowType>

All Implemented Interfaces:

Expr.InputBindingInspector, ColumnInspector, CursorFactory, StorageAdapter

public class RowBasedStorageAdapter<RowType>
extends Object
implements StorageAdapter

A StorageAdapter that is based on a stream of objects. Generally created by a RowBasedSegment.

See Also:

for implementation notes

Constructor Summary

Constructors

Constructor	Description
RowBasedStorageAdapter(Sequence<RowType> rowSequence, RowAdapter<RowType> rowAdapter, RowSignature rowSignature)

Method Summary

Modifier and Type	Method	Description
Indexed<String>	getAvailableDimensions()
Iterable<String>	getAvailableMetrics()
ColumnCapabilities	getColumnCapabilities(String column)	Returns capabilities of a particular column, if known.
int	getDimensionCardinality(String column)	Returns the number of distinct values for a column, or DimensionDictionarySelector.CARDINALITY_UNKNOWN if unknown.
org.joda.time.Interval	getInterval()
org.joda.time.DateTime	getMaxIngestedEventTime()
org.joda.time.DateTime	getMaxTime()	Metadata-only operation that returns an upper bound on ColumnHolder.TIME_COLUMN_NAME values for this adapter.
Comparable	getMaxValue(String column)	Returns the minimum value of the provided column, if known through an index, dictionary, or cache.
Metadata	getMetadata()
org.joda.time.DateTime	getMinTime()	Metadata-only operation that returns a lower bound on ColumnHolder.TIME_COLUMN_NAME values for this adapter.
Comparable	getMinValue(String column)	Returns the minimum value of the provided column, if known through an index, dictionary, or cache.
int	getNumRows()
RowSignature	getRowSignature()	Returns the row signature of the data available from this adapter.
static boolean	isQueryGranularityAllowed(org.joda.time.Interval interval, Granularity granularity)	Whether the provided time interval and granularity combination is allowed.
Sequence<Cursor>	makeCursors(Filter filter, org.joda.time.Interval queryInterval, VirtualColumns virtualColumns, Granularity gran, boolean descending, QueryMetrics<?> queryMetrics)	Creates a sequence of Cursors, one for each time-granular bucket (based on the provided Granularity).

Methods inherited from class java.lang.Object

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

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

getType

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

canVectorize, makeVectorCursor

Methods inherited from interface org.apache.druid.math.expr.Expr.InputBindingInspector

areNumeric, areNumeric, areSameTypes, areSameTypes, areScalar, areScalar, canVectorize, canVectorize

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

hasBuiltInFilters, isFromTombstone

Constructor Detail

RowBasedStorageAdapter

public RowBasedStorageAdapter(Sequence<RowType> rowSequence,
                              RowAdapter<RowType> rowAdapter,
                              RowSignature rowSignature)

Method Detail

isQueryGranularityAllowed

public static boolean isQueryGranularityAllowed(org.joda.time.Interval interval,
                                                Granularity granularity)

Whether the provided time interval and granularity combination is allowed. We restrict ETERNITY with non-ALL granularity, because allowing it would involve creating a very high number of time grains. This would cause queries to take an excessive amount of time or run out of memory.

getInterval

public org.joda.time.Interval getInterval()

Specified by:

getInterval in interface StorageAdapter

getAvailableDimensions

public Indexed<String> getAvailableDimensions()

Specified by:

getAvailableDimensions in interface StorageAdapter

getAvailableMetrics

public Iterable<String> getAvailableMetrics()

Specified by:

getAvailableMetrics in interface StorageAdapter

getRowSignature

public RowSignature getRowSignature()

Description copied from interface: StorageAdapter

Returns the row signature of the data available from this adapter. For mutable adapters, even though the signature may evolve over time, any particular object returned by this method is an immutable snapshot.

Specified by:

getRowSignature in interface StorageAdapter

getDimensionCardinality

public int getDimensionCardinality(String column)

Description copied from interface: StorageAdapter

Returns the number of distinct values for a column, or DimensionDictionarySelector.CARDINALITY_UNKNOWN if unknown. If the column doesn't exist, returns 1, because a column that doesn't exist is treated as a column of default (or null) values.

Specified by:

getDimensionCardinality in interface StorageAdapter

getMinTime

public org.joda.time.DateTime getMinTime()

Description copied from interface: StorageAdapter

Metadata-only operation that returns a lower bound on ColumnHolder.TIME_COLUMN_NAME values for this adapter. May be earlier than the actual minimum data timestamp. For QueryableIndexStorageAdapter and IncrementalIndexStorageAdapter specifically, which back regular tables (i.e. TableDataSource), this method contract is tighter: it does return the actual minimum data timestamp. This fact is leveraged by TimeBoundaryQuery to return results using metadata only.

Specified by:

getMinTime in interface StorageAdapter

getMaxTime

public org.joda.time.DateTime getMaxTime()

Description copied from interface: StorageAdapter

Metadata-only operation that returns an upper bound on ColumnHolder.TIME_COLUMN_NAME values for this adapter. May be later than the actual maximum data timestamp. For QueryableIndexStorageAdapter and IncrementalIndexStorageAdapter specifically, which back regular tables (i.e. TableDataSource), this method contract is tighter: it does return the actual maximum data timestamp. This fact is leveraged by TimeBoundaryQuery to return results using metadata only.

Specified by:

getMaxTime in interface StorageAdapter

getMinValue

@Nullable
public Comparable getMinValue(String column)

Description copied from interface: StorageAdapter

Returns the minimum value of the provided column, if known through an index, dictionary, or cache. Returns null if not known. Does not scan the column to find the minimum value.

Specified by:

getMinValue in interface StorageAdapter

getMaxValue

@Nullable
public Comparable getMaxValue(String column)

Description copied from interface: StorageAdapter

Returns the minimum value of the provided column, if known through an index, dictionary, or cache. Returns null if not known. Does not scan the column to find the maximum value.

Specified by:

getMaxValue in interface StorageAdapter

getColumnCapabilities

@Nullable
public ColumnCapabilities getColumnCapabilities(String column)

Description copied from interface: StorageAdapter

Returns capabilities of a particular column, if known. May be null if the column doesn't exist, or if the column does exist but the capabilities are unknown. The latter is possible with dynamically discovered columns. Note that StorageAdapters are representations of "real" segments, so they are not aware of any virtual columns that may be involved in a query. In general, query engines should instead use the method ColumnSelectorFactory.getColumnCapabilities(String), which returns capabilities for virtual columns as well.

Specified by:

getColumnCapabilities in interface ColumnInspector

Specified by:

getColumnCapabilities in interface StorageAdapter

Parameters:

column - column name

Returns:

capabilities, or null

getNumRows

public int getNumRows()

Specified by:

getNumRows in interface StorageAdapter

getMaxIngestedEventTime

public org.joda.time.DateTime getMaxIngestedEventTime()

Specified by:

getMaxIngestedEventTime in interface StorageAdapter

getMetadata

public Metadata getMetadata()

Specified by:

getMetadata in interface StorageAdapter

makeCursors

public Sequence<Cursor> makeCursors(@Nullable
                                    Filter filter,
                                    org.joda.time.Interval queryInterval,
                                    VirtualColumns virtualColumns,
                                    Granularity gran,
                                    boolean descending,
                                    @Nullable
                                    QueryMetrics<?> queryMetrics)

Description copied from interface: CursorFactory

Creates a sequence of Cursors, one for each time-granular bucket (based on the provided Granularity).

Specified by:

makeCursors in interface CursorFactory