org.apache.drill.exec.physical.impl.scan.project

Class ScanSchemaOrchestrator.ScanOrchestratorBuilder

java.lang.Object

org.apache.drill.exec.physical.impl.scan.project.ScanSchemaOrchestrator.ScanOrchestratorBuilder

Direct Known Subclasses:

ManagedScanFramework.ScanFrameworkBuilder, ScanTestUtils.MockScanBuilder

Enclosing class:

ScanSchemaOrchestrator

public abstract static class ScanSchemaOrchestrator.ScanOrchestratorBuilder
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
boolean	disableEmptyResults Option to disable empty results.

Constructor Summary

Constructors

Constructor and Description
ScanOrchestratorBuilder()

Method Summary

Modifier and Type	Method and Description
void	addParser(ScanLevelProjection.ScanProjectionParser parser)
void	addResolver(ReaderLevelProjection.ReaderProjectionResolver resolver)
void	allowRequiredNullColumns(boolean flag)
void	batchByteLimit(int byteLimit)
void	batchRecordLimit(int batchRecordLimit) Specify a custom batch record count.
abstract ScanOperatorEvents	buildEvents()
ScanOperatorExec	buildScan()
OperatorRecordBatch	buildScanOperator(FragmentContext fragContext, PhysicalOperator pop)
void	disableEmptyResults(boolean option)
void	enableSchemaBatch(boolean option)
void	enableSchemaSmoothing(boolean flag) Enable schema smoothing: introduces an addition level of schema resolution each time a schema changes from a reader.
CustomErrorContext	errorContext()
void	errorContext(CustomErrorContext context)
void	nullType(TypeProtos.MajorType nullType) Specify the type to use for null columns in place of the standard nullable int.
void	projection(List<SchemaPath> projection)
TupleMetadata	providedSchema()
void	providedSchema(TupleMetadata providedSchema)
void	withImplicitColumns(MetadataManager metadataMgr) Specify an optional metadata manager.

Methods inherited from class java.lang.Object

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

Field Detail

disableEmptyResults

public boolean disableEmptyResults

Option to disable empty results. An empty result occurs if no reader has any data, but at least one reader can provide a schema. In this case, the scan can return a single, empty batch, with an associated schema. This is the correct SQL result for an empty query. However, if this result triggers empty-batch bugs in other operators, we can, instead, disable this feature and return a null result set: no schema, no batch, just a "fast NONE", an immediate return of NONE from the Volcano iterator.

Disabling this option is not desirable: it means that the user gets no schema for queries that should be able to return one. So, disable this option only if we cannot find or fix empty-batch bugs.

Constructor Detail

ScanOrchestratorBuilder

public ScanOrchestratorBuilder()

Method Detail

withImplicitColumns

public void withImplicitColumns(MetadataManager metadataMgr)

Specify an optional metadata manager. Metadata is a set of constant columns with per-reader values. For file-based sources, this is usually the implicit and partition columns; but it could be other items for other data sources.

Parameters:

metadataMgr - the application-specific metadata manager to use for this scan

batchRecordLimit

public void batchRecordLimit(int batchRecordLimit)

Specify a custom batch record count. This is the maximum number of records per batch for this scan. Readers can adjust this, but the adjustment is capped at the value specified here

Parameters:

batchRecordLimit - maximum records per batch

batchByteLimit

public void batchByteLimit(int byteLimit)

nullType

public void nullType(TypeProtos.MajorType nullType)

Specify the type to use for null columns in place of the standard nullable int. This type is used for all missing columns. (Readers that need per-column control need a different mechanism.)

Parameters:

nullType - the type to use for null columns

enableSchemaSmoothing

public void enableSchemaSmoothing(boolean flag)

Enable schema smoothing: introduces an addition level of schema resolution each time a schema changes from a reader.

Parameters:

flag - true to enable schema smoothing, false to disable

allowRequiredNullColumns

public void allowRequiredNullColumns(boolean flag)

addParser

public void addParser(ScanLevelProjection.ScanProjectionParser parser)

addResolver

public void addResolver(ReaderLevelProjection.ReaderProjectionResolver resolver)

projection

public void projection(List<SchemaPath> projection)

enableSchemaBatch

public void enableSchemaBatch(boolean option)

disableEmptyResults

public void disableEmptyResults(boolean option)

providedSchema

public void providedSchema(TupleMetadata providedSchema)

providedSchema

public TupleMetadata providedSchema()

errorContext

public void errorContext(CustomErrorContext context)

errorContext

public CustomErrorContext errorContext()

buildScan

public ScanOperatorExec buildScan()

buildScanOperator

public OperatorRecordBatch buildScanOperator(FragmentContext fragContext,
                                             PhysicalOperator pop)

buildEvents

public abstract ScanOperatorEvents buildEvents()