simpledb.parallel

Class CollectConsumer

java.lang.Object

simpledb.Operator

simpledb.parallel.Exchange

simpledb.parallel.Consumer

simpledb.parallel.CollectConsumer

All Implemented Interfaces:

java.io.Serializable, DbIterator

public class CollectConsumer
extends Consumer

The consumer part of the Collect Exchange operator. A Collect operator collects tuples from all the workers. There is a collect producer on each worker, and a collect consumer on the server and a master worker if a master worker is needed. The consumer passively collects Tuples from all the paired CollectProducers

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class simpledb.parallel.Exchange

Exchange.ParallelOperatorID

Field Summary

Fields

Modifier and Type	Field and Description
private CollectProducer	child The child of a CollectConsumer must be a paired CollectProducer.
private java.util.ArrayList<TupleBag>	innerBuffer
private int	innerBufferIndex innerBufferIndex and innerBuffer are used to buffer all the TupleBags this operator has received.
private static long	serialVersionUID
private SocketInfo[]	sourceWorkers
private TupleDesc	td
private java.util.Iterator<Tuple>	tuples
private java.util.BitSet	workerEOS
private java.util.HashMap<java.lang.String,java.lang.Integer>	workerIdToIndex

Fields inherited from class simpledb.parallel.Exchange

operatorID

Constructor Summary

Constructors

Constructor and Description
CollectConsumer(CollectProducer child, Exchange.ParallelOperatorID operatorID, SocketInfo[] workers) If a child is provided, the TupleDesc is the child's TD
CollectConsumer(TupleDesc td, Exchange.ParallelOperatorID operatorID, SocketInfo[] workers) If there's no child operator, a TupleDesc is needed

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes this iterator.
protected Tuple	fetchNext() Returns the next Tuple in the iterator, or null if the iteration is finished.
DbIterator[]	getChildren()
java.lang.String	getName() Return the name of the exchange, used only to display the operator in the operator tree
TupleDesc	getTupleDesc() Returns the TupleDesc associated with this DbIterator.
(package private) java.util.Iterator<Tuple>	getTuples()
void	open() Opens the iterator.
void	rewind() Resets the iterator to the start.
void	setChildren(DbIterator[] children) Set the children(child) of this operator.

Methods inherited from class simpledb.parallel.Consumer

setBuffer, take

Methods inherited from class simpledb.parallel.Exchange

getOperatorID

Methods inherited from class simpledb.Operator

getEstimatedCardinality, hasNext, next, setEstimatedCardinality

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

tuples

private transient java.util.Iterator<Tuple> tuples

innerBufferIndex

private transient int innerBufferIndex

innerBufferIndex and innerBuffer are used to buffer all the TupleBags this operator has received. We need this because we need to support rewind.

innerBuffer

private transient java.util.ArrayList<TupleBag> innerBuffer

td

private TupleDesc td

workerEOS

private final java.util.BitSet workerEOS

sourceWorkers

private final SocketInfo[] sourceWorkers

workerIdToIndex

private final java.util.HashMap<java.lang.String,java.lang.Integer> workerIdToIndex

child

private CollectProducer child

The child of a CollectConsumer must be a paired CollectProducer.

Constructor Detail

CollectConsumer

public CollectConsumer(TupleDesc td,
               Exchange.ParallelOperatorID operatorID,
               SocketInfo[] workers)

If there's no child operator, a TupleDesc is needed

CollectConsumer

public CollectConsumer(CollectProducer child,
               Exchange.ParallelOperatorID operatorID,
               SocketInfo[] workers)

If a child is provided, the TupleDesc is the child's TD

Method Detail

getName

public java.lang.String getName()

Description copied from class: Exchange

Return the name of the exchange, used only to display the operator in the operator tree

Specified by:

getName in class Exchange

open

public void open()
          throws DbException,
                 TransactionAbortedException

Description copied from interface: DbIterator

Opens the iterator. This must be called before any of the other methods.

Specified by:

open in interface DbIterator

Overrides:

open in class Operator

Throws:

DbException - when there are problems opening/accessing the database.

TransactionAbortedException

rewind

public void rewind()
            throws DbException,
                   TransactionAbortedException

Description copied from interface: DbIterator

Resets the iterator to the start.

Throws:

DbException - when rewind is unsupported.

TransactionAbortedException

close

public void close()

Description copied from class: Operator

Closes this iterator. If overridden by a subclass, they should call super.close() in order for Operator's internal state to be consistent.

Specified by:

close in interface DbIterator

Overrides:

close in class Operator

getTupleDesc

public TupleDesc getTupleDesc()

Description copied from interface: DbIterator

Returns the TupleDesc associated with this DbIterator.

Specified by:

getTupleDesc in interface DbIterator

Specified by:

getTupleDesc in class Operator

Returns:

return the TupleDesc of the output tuples of this operator

getTuples

java.util.Iterator<Tuple> getTuples()
                              throws java.lang.InterruptedException

Throws:

java.lang.InterruptedException

fetchNext

protected Tuple fetchNext()
                   throws DbException,
                          TransactionAbortedException

Description copied from class: Operator

Returns the next Tuple in the iterator, or null if the iteration is finished. Operator uses this method to implement both next and hasNext.

Specified by:

fetchNext in class Operator

Returns:

the next Tuple in the iterator, or null if the iteration is finished.

Throws:

DbException

TransactionAbortedException

getChildren

public DbIterator[] getChildren()

Specified by:

getChildren in class Operator

Returns:

return the children DbIterators of this operator. If there is only one child, return an array of only one element. For join operators, the order of the children is not important. But they should be consistent among multiple calls.

setChildren

public void setChildren(DbIterator[] children)

Description copied from class: Operator

Set the children(child) of this operator. If the operator has only one child, children[0] should be used. If the operator is a join, children[0] and children[1] should be used.

Specified by:

setChildren in class Operator

Parameters:

children - the DbIterators which are to be set as the children(child) of this operator