Package org.apache.druid.query

Class FrameBasedInlineDataSource

java.lang.Object
org.apache.druid.query.LeafDataSource
org.apache.druid.query.FrameBasedInlineDataSource
All Implemented Interfaces:
Cacheable, DataSource
public class FrameBasedInlineDataSource extends LeafDataSource
Represents an inline datasource where the rows are embedded within the DataSource object itself.

The rows are backed by a sequence of FrameSignaturePair, which contain the Frame representation of the rows represented by the datasource.

Note that the signature of the datasource can be different from the signatures of the constituent frames that it consists of. While fetching the iterables, it is the job of this class to make sure that the rows correspond to the rowSignature. For frames that donot contain the columns present in the rowSignature, they are populated with null.

  • Constructor Details

  • Method Details

    • getFrames

      public List<FrameSignaturePair> getFrames()

    • getRowSignature

      public RowSignature getRowSignature()

    • getRowsAsSequence

      public Sequence<Object[]> getRowsAsSequence()

    • 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.

    • 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.

    • isGlobal

      public boolean isGlobal()
      Description copied from interface: DataSource
      Decides if this datasource can be accessed globally.

      This means that all servers have a full copy of this datasource.

      Examples: inline table, lookup.

    • isProcessable

      public boolean isProcessable()
      Description copied from interface: DataSource
      Communicates that this DataSource can be directly used to run a Query.

      A Processable datasource must pack the necessary logic into the DataSource.createSegmentMapFunction(Query).

      Processable examples are: TableDataSource, InlineDataSource, FilteredDataSource. Non-processable ones are those which need further pre-processing before running them. examples are: QueryDataSource and join which are not supported directly.

    • 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.
      Returns:
      the cache key to be used as part of query cache key