org.apache.drill.exec.physical.resultSet.impl

Class ResultSetOptionBuilder

java.lang.Object

org.apache.drill.exec.physical.resultSet.impl.ResultSetOptionBuilder

public class ResultSetOptionBuilder
extends Object

Builder for the options for the row set loader. Reasonable defaults are provided for all options; use the default options for test code or for clients that don't need special settings.

Field Summary

Fields

Modifier and Type	Field and Description
protected CustomErrorContext	errorContext Error message context
protected long	maxBatchSize
protected ProjectionFilter	projectionFilter
protected RequestedTuple	projectionSet
protected TupleMetadata	readerSchema
protected int	rowCountLimit
protected long	scanLimit
protected ResultVectorCache	vectorCache
protected int	vectorSizeLimit

Constructor Summary

Constructors

Constructor and Description
ResultSetOptionBuilder()

Method Summary

Modifier and Type	Method and Description
ResultSetOptionBuilder	batchSizeLimit(int bytes)
ResultSetLoaderImpl.ResultSetOptions	build()
ResultSetOptionBuilder	errorContext(CustomErrorContext context) Provides context for error messages.
ResultSetOptionBuilder	limit(long limit)
ResultSetOptionBuilder	projection(RequestedTuple projSet)
ResultSetOptionBuilder	projectionFilter(ProjectionFilter projectionFilter)
ResultSetOptionBuilder	readerSchema(TupleMetadata readerSchema) Clients can use the row set builder in several ways: Provide the schema up front, when known, by using this method to provide the schema. Discover the schema on the fly, adding columns during the write operation.
ResultSetOptionBuilder	rowCountLimit(int limit) Specify the maximum number of rows per batch.
ResultSetOptionBuilder	vectorCache(ResultVectorCache vectorCache) Downstream operators require "vector persistence": the same vector must represent the same column in every batch.

Methods inherited from class java.lang.Object

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

Field Detail

vectorSizeLimit

protected int vectorSizeLimit

rowCountLimit

protected int rowCountLimit

vectorCache

protected ResultVectorCache vectorCache

projectionSet

protected RequestedTuple projectionSet

projectionFilter

protected ProjectionFilter projectionFilter

readerSchema

protected TupleMetadata readerSchema

maxBatchSize

protected long maxBatchSize

scanLimit

protected long scanLimit

errorContext

protected CustomErrorContext errorContext

Error message context

Constructor Detail

ResultSetOptionBuilder

public ResultSetOptionBuilder()

Method Detail

rowCountLimit

public ResultSetOptionBuilder rowCountLimit(int limit)

Specify the maximum number of rows per batch. Defaults to BaseValueVector.INITIAL_VALUE_ALLOCATION. Batches end either when this limit is reached, or when a vector overflows, whichever occurs first. The limit is capped at ValueVector.MAX_ROW_COUNT.

Parameters:

limit - the row count limit

Returns:

this builder

batchSizeLimit

public ResultSetOptionBuilder batchSizeLimit(int bytes)

vectorCache

public ResultSetOptionBuilder vectorCache(ResultVectorCache vectorCache)

Downstream operators require "vector persistence": the same vector must represent the same column in every batch. For the scan operator, which creates multiple readers, this can be a challenge. The vector cache provides a transparent mechanism to enable vector persistence by returning the same vector for a set of independent readers. By default, the code uses a "null" cache which creates a new vector on each request. If a true cache is needed, the caller must provide one here.

readerSchema

public ResultSetOptionBuilder readerSchema(TupleMetadata readerSchema)

Clients can use the row set builder in several ways:

• Provide the schema up front, when known, by using this method to provide the schema.
• Discover the schema on the fly, adding columns during the write operation. Leave this method unset to start with an empty schema.
• A combination of the above.

Parameters:

readerSchema - the initial schema for the loader

Returns:

this builder

projection

public ResultSetOptionBuilder projection(RequestedTuple projSet)

projectionFilter

public ResultSetOptionBuilder projectionFilter(ProjectionFilter projectionFilter)

limit

public ResultSetOptionBuilder limit(long limit)

errorContext

public ResultSetOptionBuilder errorContext(CustomErrorContext context)

Provides context for error messages.

build

public ResultSetLoaderImpl.ResultSetOptions build()