public final class GatherHint extends AbstractDeferredRecordOperator
It is also possible to force data to be staged to disk, breaking physical streaming; consumers of the output will run in a physical graph executed after the physical graph executing this operator. Even if not forced, the transition from parallel to non-parallel may cause staging to occur.
Normally these actions happens automatically in a logical graph as required, but this operator provides a mechanism for explicit control.
By definition, this is a non-parallel operator.
input, output
Constructor and Description |
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GatherHint()
Forces a gather of parallel streams of data.
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Modifier and Type | Method and Description |
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protected void |
compose(DeferredCompositionContext ctx)
Compose the body of this operator.
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protected void |
computeMetadata(StreamingMetadataContext ctx)
Implementations must adhere to all of the contracts specified
by
StreamingOperator.computeMetadata(com.pervasive.datarush.operators.StreamingMetadataContext) . |
DataOrdering |
getDataOrdering()
Gets the data ordering of the output.
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boolean |
isForceStaging()
Indicates whether data will be forcibly staged
to disk.
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void |
setDataOrdering(DataOrdering dataOrdering)
Sets the data ordering of the output.
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void |
setForceStaging(boolean forceStaging)
Sets whether data must be staged to disk.
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getInput, getOutput
computeOutputTypes
disableParallelism, getInputPorts, getOutputPorts, newInput, newInput, newOutput, newRecordInput, newRecordInput, newRecordOutput, notifyError
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
disableParallelism, getInputPorts, getOutputPorts
public GatherHint()
public DataOrdering getDataOrdering()
public void setDataOrdering(DataOrdering dataOrdering)
dataOrdering
- the requested data orderingpublic boolean isForceStaging()
public void setForceStaging(boolean forceStaging)
forceStaging
- indicates whether the data
must be stagedprotected void computeMetadata(StreamingMetadataContext ctx)
DeferredCompositeOperator
StreamingOperator.computeMetadata(com.pervasive.datarush.operators.StreamingMetadataContext)
. In addition,
DeferredCompositeOperators must declare required metadata so
as to satisfy requirements of the operators that are added
during DeferredCompositeOperator.compose(com.pervasive.datarush.operators.DeferredCompositionContext)
.computeMetadata
in class DeferredCompositeOperator
ctx
- the contextprotected void compose(DeferredCompositionContext ctx)
DeferredCompositeOperator
OperatorComposable.add(O)
OperatorComposable.connect(P, P)
. This includes
connections from the composite's input ports to sub-operators, connections between sub-operators, and
connections from sub-operators output ports to the composite's output portscompose
in class DeferredCompositeOperator
ctx
- the contextCopyright © 2016 Actian Corporation. All rights reserved.