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

Class TestScanOperExecSmoothing

java.lang.Object

DrillTest

org.apache.drill.test.SubOperatorTest

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

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

public class TestScanOperExecSmoothing
extends BaseScanOperatorExecTest

Test the ability of the scan operator to "absorb" schema changes by "smoothing" out data types and modes across readers. Schema smoothing is helpful when there is no output schema, but only works within the context of a single scan operator: it cannot help when a query has multiple scans, each in its own fragment.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.drill.exec.physical.impl.scan.BaseScanOperatorExecTest

BaseScanOperatorExecTest.BaseMockBatchReader, BaseScanOperatorExecTest.BaseScanFixtureBuilder, BaseScanOperatorExecTest.MockEarlySchemaReader

Field Summary

Fields inherited from class org.apache.drill.test.SubOperatorTest

dirTestWatcher, fixture

Constructor Summary

Constructors

Constructor and Description
TestScanOperExecSmoothing()

Method Summary

Modifier and Type	Method and Description
void	testSchemaChange() Multiple readers with a schema change between them.
void	testSchemaChangeNoSchemaBatch()
void	testSchemaSmoothing() Test the ability of the scan operator to "smooth" out schema changes by reusing the type from a previous reader, if known.

Methods inherited from class org.apache.drill.exec.physical.impl.scan.BaseScanOperatorExecTest

expectedSchema, makeExpected, makeExpected, simpleBuilder, simpleFixture, verifyBatch

Methods inherited from class org.apache.drill.test.SubOperatorTest

classSetup, classTeardown

Methods inherited from class java.lang.Object

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

Constructor Detail

TestScanOperExecSmoothing

public TestScanOperExecSmoothing()

Method Detail

testSchemaChange

public void testSchemaChange()

Multiple readers with a schema change between them.

testSchemaChangeNoSchemaBatch

public void testSchemaChangeNoSchemaBatch()

testSchemaSmoothing

public void testSchemaSmoothing()

Test the ability of the scan operator to "smooth" out schema changes by reusing the type from a previous reader, if known. That is, given three readers:
(a, b)
(b)
(a, b)
Then the type of column a should be preserved for the second reader that does not include a. This works if a is nullable. If so, a's type will be used for the empty column, rather than the usual nullable int.

Full testing of smoothing is done in {#link TestScanProjector}. Here we just make sure that the smoothing logic is available via the scan operator.