org.apache.drill.exec.store.sys

Class SystemTableScan

java.lang.Object

org.apache.drill.exec.physical.base.AbstractBase

org.apache.drill.exec.physical.base.AbstractGroupScan

org.apache.drill.exec.store.sys.SystemTableScan

All Implemented Interfaces:

Iterable<PhysicalOperator>, GraphValue<PhysicalOperator>, FragmentLeaf, GroupScan, HasAffinity, Leaf, PhysicalOperator, Scan, SubScan

public class SystemTableScan
extends AbstractGroupScan
implements SubScan

Field Summary

Fields inherited from class org.apache.drill.exec.physical.base.AbstractBase

INIT_ALLOCATION, initialAllocation, MAX_ALLOCATION, maxAllocation

Fields inherited from interface org.apache.drill.common.graph.GraphValue

logger

Fields inherited from interface org.apache.drill.exec.physical.base.GroupScan

ALL_COLUMNS, NO_COLUMN_STATS

Constructor Summary

Constructors

Constructor and Description
SystemTableScan(SystemTable table, StoragePluginRegistry engineRegistry)
SystemTableScan(SystemTable table, SystemTablePlugin plugin)

Method Summary

Methods

Modifier and Type	Method and Description
void	applyAssignments(List<CoordinationProtos.DrillbitEndpoint> endpoints)
GroupScan	clone(List<SchemaPath> columns) Returns a clone of GroupScan instance, except that the new GroupScan will use the provided list of columns .
String	getDigest() Returns a signature of the GroupScan which should usually be composed of all its attributes which could describe it uniquely.
DistributionAffinity	getDistributionAffinity() Get distribution affinity which describes the parallelization strategy of the operator.
long	getInitialAllocation()
long	getMaxAllocation()
int	getMaxParallelizationWidth()
int	getMinParallelizationWidth() At minimum, the GroupScan requires these many fragments to run.
PhysicalOperator	getNewWithChildren(List<PhysicalOperator> children) Regenerate with this node with a new set of children.
List<EndpointAffinity>	getOperatorAffinity() If distributed, the scan needs to happen on every node.
int	getOperatorType()
SystemTablePlugin	getPlugin()
ScanStats	getScanStats() System tables do not need stats.
SubScan	getSpecificScan(int minorFragmentId)
SystemTable	getTable()

Methods inherited from class org.apache.drill.exec.physical.base.AbstractGroupScan

accept, applyLimit, canPushdownProjects, enforceWidth, getColumnValueCount, getFiles, getPartitionColumns, getScanStats, hasFiles, isExecutable, iterator, supportsLimitPushdown, supportsPartitionFilterPushdown

Methods inherited from class org.apache.drill.exec.physical.base.AbstractBase

accept, getCost, getOperatorId, getSVMode, getUserName, isBufferedOperator, setCost, setMaxAllocation, setOperatorId

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.drill.exec.physical.base.PhysicalOperator

accept, getCost, getOperatorId, getSVMode, getUserName, isBufferedOperator, isExecutable, setCost, setMaxAllocation, setOperatorId

Methods inherited from interface org.apache.drill.common.graph.GraphValue

accept

Methods inherited from interface java.lang.Iterable

iterator

Constructor Detail

SystemTableScan

public SystemTableScan(SystemTable table,
               StoragePluginRegistry engineRegistry)
                throws IOException,
                       ExecutionSetupException

Throws:

IOException

ExecutionSetupException

SystemTableScan

public SystemTableScan(SystemTable table,
               SystemTablePlugin plugin)

Method Detail

getScanStats

public ScanStats getScanStats()

System tables do not need stats.

Overrides:

getScanStats in class AbstractGroupScan

Returns:

a trivial stats table

getNewWithChildren

public PhysicalOperator getNewWithChildren(List<PhysicalOperator> children)
                                    throws ExecutionSetupException

Description copied from interface: PhysicalOperator

Regenerate with this node with a new set of children. This is used in the case of materialization or optimization.

Specified by:

getNewWithChildren in interface PhysicalOperator

Returns:

Throws:

ExecutionSetupException

applyAssignments

public void applyAssignments(List<CoordinationProtos.DrillbitEndpoint> endpoints)
                      throws PhysicalOperatorSetupException

Specified by:

applyAssignments in interface GroupScan

Throws:

PhysicalOperatorSetupException

getSpecificScan

public SubScan getSpecificScan(int minorFragmentId)
                        throws ExecutionSetupException

Specified by:

getSpecificScan in interface GroupScan

Throws:

ExecutionSetupException

getMaxParallelizationWidth

public int getMaxParallelizationWidth()

Specified by:

getMaxParallelizationWidth in interface GroupScan

getMinParallelizationWidth

public int getMinParallelizationWidth()

Description copied from interface: GroupScan

At minimum, the GroupScan requires these many fragments to run. Currently, this is used in SimpleParallelizer

Specified by:

getMinParallelizationWidth in interface GroupScan

Overrides:

getMinParallelizationWidth in class AbstractGroupScan

Returns:

the minimum number of fragments that should run

getInitialAllocation

public long getInitialAllocation()

Specified by:

getInitialAllocation in interface PhysicalOperator

Overrides:

getInitialAllocation in class AbstractGroupScan

Returns:

The memory to preallocate for this operator

getMaxAllocation

public long getMaxAllocation()

Specified by:

getMaxAllocation in interface PhysicalOperator

Overrides:

getMaxAllocation in class AbstractGroupScan

Returns:

The maximum memory this operator can allocate

getDigest

public String getDigest()

Description copied from interface: GroupScan

Returns a signature of the GroupScan which should usually be composed of all its attributes which could describe it uniquely.

Specified by:

getDigest in interface GroupScan

getOperatorType

public int getOperatorType()

Specified by:

getOperatorType in interface PhysicalOperator

Overrides:

getOperatorType in class AbstractGroupScan

getOperatorAffinity

public List<EndpointAffinity> getOperatorAffinity()

If distributed, the scan needs to happen on every node. Since width is enforced, the number of fragments equals number of Drillbits. And here we set, each endpoint as mandatory assignment required to ensure every Drillbit executes a fragment.

Specified by:

getOperatorAffinity in interface HasAffinity

Overrides:

getOperatorAffinity in class AbstractGroupScan

Returns:

the Drillbit endpoint affinities

getDistributionAffinity

public DistributionAffinity getDistributionAffinity()

Description copied from interface: HasAffinity

Get distribution affinity which describes the parallelization strategy of the operator.

Specified by:

getDistributionAffinity in interface HasAffinity

Overrides:

getDistributionAffinity in class AbstractGroupScan

clone

public GroupScan clone(List<SchemaPath> columns)

Description copied from interface: GroupScan

Returns a clone of GroupScan instance, except that the new GroupScan will use the provided list of columns .

Specified by:

clone in interface GroupScan

Overrides:

clone in class AbstractGroupScan

getTable

public SystemTable getTable()

getPlugin

public SystemTablePlugin getPlugin()