org.apache.druid.query

Class InlineDataSource

java.lang.Object

org.apache.druid.query.InlineDataSource

All Implemented Interfaces:

DataSource

public class InlineDataSource
extends Object
implements DataSource

Represents an inline datasource, where the rows are embedded within the DataSource object itself.

The rows are backed by an Iterable, which can be lazy or not. Lazy datasources will only be iterated if someone calls getRows() and iterates the result, or until someone calls getRowsAsList().

Method Summary

Modifier and Type	Method and Description
Function<SegmentReference,SegmentReference>	createSegmentMapFunction(Query query, AtomicLong cpuTimeAcc) Returns a segment function on to how to segment should be modified.
boolean	equals(Object o)
static InlineDataSource	fromIterable(Iterable<Object[]> rows, RowSignature signature) Creates an inline datasource from an Iterable.
byte[]	getCacheKey() Compute a cache key prefix for a data source.
List<DataSource>	getChildren() Returns datasources that this datasource depends on.
List<String>	getColumnNames()
List<ColumnType>	getColumnTypes()
Iterable<Object[]>	getRows() Returns rows as an Iterable.
List<Object[]>	getRowsAsList() Returns rows as a list.
RowSignature	getRowSignature() Returns the row signature (map of column name to type) for this inline datasource.
Set<String>	getTableNames() Returns the names of all table datasources involved in this query.
int	hashCode()
boolean	isCacheable(boolean isBroker) Returns true if queries on this dataSource are cacheable at both the result level and per-segment level.
boolean	isConcrete() Returns true if this datasource represents concrete data that can be scanned via a Segment adapter of some kind.
boolean	isGlobal() Returns true if all servers have a full copy of this datasource.
RowAdapter<Object[]>	rowAdapter()
String	toString()
DataSource	withChildren(List<DataSource> children) Return a new DataSource, identical to this one, with different children.
DataSource	withUpdatedDataSource(DataSource newSource) Returns an updated datasource based on the specified new source.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

fromIterable

public static InlineDataSource fromIterable(Iterable<Object[]> rows,
                                            RowSignature signature)

Creates an inline datasource from an Iterable. The Iterable will not be iterated until someone calls getRows() and iterates the result, or until someone calls getRowsAsList().

Parameters:

rows - rows, each of the same length as signature.size()

signature - row signature

getTableNames

public Set<String> getTableNames()

Description copied from interface: DataSource

Returns the names of all table datasources involved in this query. Does not include names for non-tables, like lookups or inline datasources.

Specified by:

getTableNames in interface DataSource

getColumnNames

public List<String> getColumnNames()

getColumnTypes

@Nullable
public List<ColumnType> getColumnTypes()

getRowsAsList

public List<Object[]> getRowsAsList()

Returns rows as a list. If the original Iterable behind this datasource was a List, this method will return it as-is, without copying it. Otherwise, this method will walk the iterable and copy it into a List before returning.

getRows

public Iterable<Object[]> getRows()

Returns rows as an Iterable.

getChildren

public List<DataSource> getChildren()

Description copied from interface: DataSource

Returns datasources that this datasource depends on. Will be empty for leaf datasources like 'table'.

Specified by:

getChildren in interface DataSource

withChildren

public DataSource withChildren(List<DataSource> children)

Description copied from interface: DataSource

Return a new DataSource, identical to this one, with different children. The number of children must be equal to the number of children that this datasource already has.

Specified by:

withChildren in interface DataSource

isCacheable

public boolean isCacheable(boolean isBroker)

Description copied from interface: DataSource

Returns true if queries on this dataSource are cacheable at both the result level and per-segment level. Currently, dataSources that do not actually reference segments (like 'inline'), are not cacheable since cache keys are always based on segment identifiers.

Specified by:

isCacheable in interface DataSource

isGlobal

public boolean isGlobal()

Description copied from interface: DataSource

Returns true if all servers have a full copy of this datasource. True for things like inline, lookup, etc, or for queries of those. Currently this is coupled with joinability - if this returns true then the query engine expects there exists a JoinableFactory which might build a Joinable for this datasource directly. If a subquery 'inline' join is required to join this datasource on the right hand side, then this value must be false for now. In the future, instead of directly using this method, the query planner and engine should consider JoinableFactory.isDirectlyJoinable(DataSource) when determining if the right hand side is directly joinable, which would allow decoupling this property from joins.

Specified by:

isGlobal in interface DataSource

isConcrete

public boolean isConcrete()

Description copied from interface: DataSource

Returns true if this datasource represents concrete data that can be scanned via a Segment adapter of some kind. True for e.g. 'table' but not for 'query' or 'join'.

Specified by:

isConcrete in interface DataSource

See Also:

which uses this, which uses this

createSegmentMapFunction

public Function<SegmentReference,SegmentReference> createSegmentMapFunction(Query query,
                                                                            AtomicLong cpuTimeAcc)

Description copied from interface: DataSource

Returns a segment function on to how to segment should be modified.

Specified by:

createSegmentMapFunction in interface DataSource

Parameters:

query - the input query

cpuTimeAcc - the cpu time accumulator

Returns:

the segment function

withUpdatedDataSource

public DataSource withUpdatedDataSource(DataSource newSource)

Description copied from interface: DataSource

Returns an updated datasource based on the specified new source.

Specified by:

withUpdatedDataSource in interface DataSource

Parameters:

newSource - the new datasource to be used to update an existing query

Returns:

the updated datasource to be used

getCacheKey

public byte[] getCacheKey()

Description copied from interface: DataSource

Compute a cache key prefix for a data source. This includes the data sources that participate in the RHS of a join as well as any query specific constructs associated with join data source such as base table filter. This key prefix can be used in segment level cache or result level cache. The function can return following - Non-empty byte array - If there is join datasource involved and caching is possible. The result includes join condition expression, join type and cache key returned by joinable factory for each PreJoinableClause - NULL - There is a join but caching is not possible. It may happen if one of the participating datasource in the JOIN is not cacheable.

Specified by:

getCacheKey in interface DataSource

Returns:

the cache key to be used as part of query cache key

getRowSignature

public RowSignature getRowSignature()

Returns the row signature (map of column name to type) for this inline datasource. Note that types may be null, meaning we know we have a column with a certain name, but we don't know what its type is.

rowAdapter

public RowAdapter<Object[]> rowAdapter()

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object