/// <summary>
/// No more elements will be added, so we can sort the group now.
/// </summary>
internal void DoneAdding()
{
Debug.Assert(_values != null);
int count = _values.Count;
ListChunk <Pair <TOrderKey, TElement> >?curChunk = _values;
while ((curChunk = curChunk.Next) != null)
{
count += curChunk.Count;
}
TElement[] values = new TElement[count];
TOrderKey[] orderKeys = new TOrderKey[count];
int idx = 0;
foreach (Pair <TOrderKey, TElement> p in _values)
{
orderKeys[idx] = p.First;
values[idx] = p.Second;
idx++;
}
Array.Sort(orderKeys, values, _orderComparer);
_sortedValues = values;
#if DEBUG
_values = null; // Any future calls to Add() or DoneAdding() will fail
#endif
}
/// <summary>
/// Allocates a new root chunk of a particular size.
/// </summary>
internal ListChunk(int size)
{
Contract.Assert(size > 0);
_chunk = new TInputOutput[size];
_chunkCount = 0;
_tailChunk = this;
}
private readonly IComparer <TOrderKey> _orderComparer; // Comparer for order keys
/// <summary>
/// Constructs a new grouping
/// </summary>
internal OrderedGroupByGrouping(
TGroupKey groupKey,
IComparer <TOrderKey> orderComparer)
{
_groupKey = groupKey;
_values = new ListChunk <Pair <TOrderKey, TElement> >(INITIAL_CHUNK_SIZE);
_orderComparer = orderComparer;
}
public IEnumerator <TInputOutput> GetEnumerator()
{
for (ListChunk <TInputOutput> iteratorVariable0 = (ListChunk <TInputOutput>) this; iteratorVariable0 != null; iteratorVariable0 = iteratorVariable0.m_nextChunk)
{
for (int i = 0; i < iteratorVariable0.m_chunkCount; i++)
{
yield return(iteratorVariable0.m_chunk[i]);
}
}
}
internal HashRepartitionEnumerator(QueryOperatorEnumerator <TInputOutput, TIgnoreKey> source, int partitionCount, int partitionIndex, Func <TInputOutput, THashKey> keySelector, HashRepartitionStream <TInputOutput, THashKey, int> repartitionStream, CountdownEvent barrier, ListChunk <Pair <TInputOutput, THashKey> >[,] valueExchangeMatrix, CancellationToken cancellationToken)
{
this.m_source = source;
this.m_partitionCount = partitionCount;
this.m_partitionIndex = partitionIndex;
this.m_keySelector = keySelector;
this.m_repartitionStream = repartitionStream;
this.m_barrier = barrier;
this.m_valueExchangeMatrix = valueExchangeMatrix;
this.m_cancellationToken = cancellationToken;
}
internal void Add(TInputOutput e)
{
ListChunk <TInputOutput> tailChunk = this.m_tailChunk;
if (tailChunk.m_chunkCount == tailChunk.m_chunk.Length)
{
this.m_tailChunk = new ListChunk <TInputOutput>(tailChunk.m_chunkCount * 2);
tailChunk = tailChunk.m_nextChunk = this.m_tailChunk;
}
tailChunk.m_chunk[tailChunk.m_chunkCount++] = e;
}
internal UnorderedHashRepartitionStream(PartitionedStream <TInputOutput, TIgnoreKey> inputStream, Func <TInputOutput, THashKey> keySelector, IEqualityComparer <THashKey> keyComparer, IEqualityComparer <TInputOutput> elementComparer, CancellationToken cancellationToken) : base(inputStream.PartitionCount, Util.GetDefaultComparer <int>(), keyComparer, elementComparer)
{
base.m_partitions = (QueryOperatorEnumerator <Pair <TInputOutput, THashKey>, int>[]) new HashRepartitionEnumerator <TInputOutput, THashKey, TIgnoreKey> [inputStream.PartitionCount];
CountdownEvent barrier = new CountdownEvent(inputStream.PartitionCount);
ListChunk <Pair <TInputOutput, THashKey> >[,] valueExchangeMatrix = new ListChunk <Pair <TInputOutput, THashKey> > [inputStream.PartitionCount, inputStream.PartitionCount];
for (int i = 0; i < inputStream.PartitionCount; i++)
{
base.m_partitions[i] = new HashRepartitionEnumerator <TInputOutput, THashKey, TIgnoreKey>(inputStream[i], inputStream.PartitionCount, i, keySelector, this, barrier, valueExchangeMatrix, cancellationToken);
}
}
/// <summary>
/// Adds an element to this chunk. Only ever called on the root.
/// </summary>
/// <param name="e">The new element.</param>
internal void Add(TInputOutput e)
{
ListChunk <TInputOutput> tail = _tailChunk;
if (tail._chunkCount == tail._chunk.Length)
{
_tailChunk = new ListChunk <TInputOutput>(tail._chunkCount * 2);
tail = (tail._nextChunk = _tailChunk);
}
tail._chunk[tail._chunkCount++] = e;
}
/// <summary>
/// Adds a value/ordering key pair to the list.
/// </summary>
/// <param name="value">value to add</param>
/// <param name="orderKey">ordering key</param>
/// <returns>if true, the internal memory has changed</returns>
/// <remarks>
/// As this is a value type, if the internal memory changes,
/// then the changes need to be reflected (to a HashLookup, for example)
/// as necessary
/// </remarks>
internal bool Add(TElement value, TOrderKey orderKey)
{
bool requiresMemoryChange = (_tail == null);
if (requiresMemoryChange)
{
_tail = new ListChunk <Pair <TElement, TOrderKey> >(INITIAL_CHUNK_SIZE);
}
_tail.Add(CreatePair(value, orderKey));
return(requiresMemoryChange);
}
/// <summary>
/// Fetches an enumerator to walk the elements in all chunks rooted from this one.
/// </summary>
public IEnumerator <TInputOutput> GetEnumerator()
{
ListChunk <TInputOutput> curr = this;
while (curr != null)
{
for (int i = 0; i < curr._chunkCount; i++)
{
yield return(curr._chunk[i]);
}
Contract.Assert(curr._chunkCount == curr._chunk.Length || curr._nextChunk == null);
curr = curr._nextChunk;
}
}
private void EnumerateAndRedistributeElements()
{
Mutables <TInputOutput, THashKey, TOrderKey> mutables = this.m_mutables;
ListChunk <Pair <TInputOutput, THashKey> >[] chunkArray = new ListChunk <Pair <TInputOutput, THashKey> > [this.m_partitionCount];
ListChunk <TOrderKey>[] chunkArray2 = new ListChunk <TOrderKey> [this.m_partitionCount];
TInputOutput currentElement = default(TInputOutput);
TOrderKey currentKey = default(TOrderKey);
int num = 0;
while (this.m_source.MoveNext(ref currentElement, ref currentKey))
{
int num2;
if ((num++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(this.m_cancellationToken);
}
THashKey key = default(THashKey);
if (this.m_keySelector != null)
{
key = this.m_keySelector(currentElement);
num2 = this.m_repartitionStream.GetHashCode(key) % this.m_partitionCount;
}
else
{
num2 = this.m_repartitionStream.GetHashCode(currentElement) % this.m_partitionCount;
}
ListChunk <Pair <TInputOutput, THashKey> > chunk = chunkArray[num2];
ListChunk <TOrderKey> chunk2 = chunkArray2[num2];
if (chunk == null)
{
chunkArray[num2] = chunk = new ListChunk <Pair <TInputOutput, THashKey> >(0x80);
chunkArray2[num2] = chunk2 = new ListChunk <TOrderKey>(0x80);
}
chunk.Add(new Pair <TInputOutput, THashKey>(currentElement, key));
chunk2.Add(currentKey);
}
for (int i = 0; i < this.m_partitionCount; i++)
{
this.m_valueExchangeMatrix[this.m_partitionIndex, i] = chunkArray[i];
this.m_keyExchangeMatrix[this.m_partitionIndex, i] = chunkArray2[i];
}
this.m_barrier.Signal();
mutables.m_currentBufferIndex = this.m_partitionIndex;
mutables.m_currentBuffer = chunkArray[this.m_partitionIndex];
mutables.m_currentKeyBuffer = chunkArray2[this.m_partitionIndex];
mutables.m_currentIndex = -1;
}
public bool Add(THashKey hashKey, TElement element, TOrderKey orderKey)
{
bool hasCollision = true;
ListChunk <TElement>?currentValue = default(ListChunk <TElement>);
if (!_base.TryGetValue(hashKey, ref currentValue))
{
const int INITIAL_CHUNK_SIZE = 2;
currentValue = new ListChunk <TElement>(INITIAL_CHUNK_SIZE);
_base.Add(hashKey, currentValue);
hasCollision = false;
}
currentValue.Add(element);
return(hasCollision);
}
//---------------------------------------------------------------------------------------
// Creates a new repartitioning enumerator.
//
// Arguments:
// source - the data stream from which to pull elements
// useOrdinalOrderPreservation - whether order preservation is required
// partitionCount - total number of partitions
// partitionIndex - this operator's unique partition index
// repartitionStream - the stream object to use for partition selection
// barrier - a latch used to signal task completion
// buffers - a set of buffers for inter-task communication
//
internal HashRepartitionEnumerator(
QueryOperatorEnumerator <TInputOutput, TIgnoreKey> source, int partitionCount, int partitionIndex,
Func <TInputOutput, THashKey> keySelector, HashRepartitionStream <TInputOutput, THashKey, int> repartitionStream,
CountdownEvent barrier, ListChunk <Pair <TInputOutput, THashKey> >[,] valueExchangeMatrix, CancellationToken cancellationToken)
{
Contract.Assert(source != null);
Contract.Assert(keySelector != null || typeof(THashKey) == typeof(NoKeyMemoizationRequired));
Contract.Assert(repartitionStream != null);
Contract.Assert(barrier != null);
Contract.Assert(valueExchangeMatrix != null);
Contract.Assert(valueExchangeMatrix.GetLength(0) == partitionCount, "expected square matrix of buffers (NxN)");
Contract.Assert(valueExchangeMatrix.GetLength(1) == partitionCount, "expected square matrix of buffers (NxN)");
Contract.Assert(0 <= partitionIndex && partitionIndex < partitionCount);
m_source = source;
m_partitionCount = partitionCount;
m_partitionIndex = partitionIndex;
m_keySelector = keySelector;
m_repartitionStream = repartitionStream;
m_barrier = barrier;
m_valueExchangeMatrix = valueExchangeMatrix;
m_cancellationToken = cancellationToken;
}
//-----------------------------------------------------------------------------------
// Builds the hash lookup, transforming from TSource to TElement through whatever means is appropriate.
//
protected override HashLookup <Wrapper <TGroupKey>, ListChunk <TElement> > BuildHashLookup()
{
HashLookup <Wrapper <TGroupKey>, ListChunk <TElement> > hashlookup =
new HashLookup <Wrapper <TGroupKey>, ListChunk <TElement> >(new WrapperEqualityComparer <TGroupKey>(_keyComparer));
Pair <TSource, TGroupKey> sourceElement = default(Pair <TSource, TGroupKey>);
TOrderKey sourceKeyUnused = default(TOrderKey) !;
int i = 0;
while (_source.MoveNext(ref sourceElement, ref sourceKeyUnused))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
_cancellationToken.ThrowIfCancellationRequested();
}
;
// Generate a key and place it into the hashtable.
Wrapper <TGroupKey> key = new Wrapper <TGroupKey>(sourceElement.Second);
// If the key already exists, we just append it to the existing list --
// otherwise we will create a new one and add it to that instead.
ListChunk <TElement>?currentValue = null;
if (!hashlookup.TryGetValue(key, ref currentValue))
{
const int INITIAL_CHUNK_SIZE = 2;
currentValue = new ListChunk <TElement>(INITIAL_CHUNK_SIZE);
hashlookup.Add(key, currentValue);
}
Debug.Assert(currentValue != null);
// Call to the base class to yield the current value.
currentValue.Add(_elementSelector(sourceElement.First));
}
return(hashlookup);
}
protected override HashLookup <Wrapper <TGroupKey>, ListChunk <TSource> > BuildHashLookup()
{
HashLookup <Wrapper <TGroupKey>, ListChunk <TSource> > lookup = new HashLookup <Wrapper <TGroupKey>, ListChunk <TSource> >(new WrapperEqualityComparer <TGroupKey>(base.m_keyComparer));
Pair <TSource, TGroupKey> currentElement = new Pair <TSource, TGroupKey>();
TOrderKey currentKey = default(TOrderKey);
int num = 0;
while (base.m_source.MoveNext(ref currentElement, ref currentKey))
{
if ((num++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(base.m_cancellationToken);
}
Wrapper <TGroupKey> key = new Wrapper <TGroupKey>(currentElement.Second);
ListChunk <TSource> chunk = null;
if (!lookup.TryGetValue(key, ref chunk))
{
chunk = new ListChunk <TSource>(2);
lookup.Add(key, chunk);
}
chunk.Add(currentElement.First);
}
return(lookup);
}
//---------------------------------------------------------------------------------------
// Creates a new partition exchange operator.
//
internal UnorderedHashRepartitionStream(
PartitionedStream <TInputOutput, TIgnoreKey> inputStream,
Func <TInputOutput, THashKey> keySelector, IEqualityComparer <THashKey> keyComparer, IEqualityComparer <TInputOutput> elementComparer,
CancellationToken cancellationToken)
: base(inputStream.PartitionCount, Util.GetDefaultComparer <int>(), keyComparer, elementComparer)
{
// Create our array of partitions.
m_partitions = new HashRepartitionEnumerator <TInputOutput, THashKey, TIgnoreKey> [inputStream.PartitionCount];
// Initialize state shared among the partitions. A latch and a matrix of buffers. Note that
// the actual elements in the buffer array are lazily allocated if needed.
CountdownEvent barrier = new CountdownEvent(inputStream.PartitionCount);
ListChunk <Pair <TInputOutput, THashKey> >[,] valueExchangeMatrix =
new ListChunk <Pair <TInputOutput, THashKey> > [inputStream.PartitionCount, inputStream.PartitionCount];
// Now construct each partition object.
for (int i = 0; i < inputStream.PartitionCount; i++)
{
m_partitions[i] = new HashRepartitionEnumerator <TInputOutput, THashKey, TIgnoreKey>(
inputStream[i], inputStream.PartitionCount, i, keySelector, this,
barrier, valueExchangeMatrix, cancellationToken);
}
}
internal ListChunk(int size)
{
this.m_chunk = new TInputOutput[size];
this.m_chunkCount = 0;
this.m_tailChunk = (ListChunk <TInputOutput>) this;
}
//---------------------------------------------------------------------------------------
// MoveNext implements all the hash-join logic noted earlier. When it is called first, it
// will execute the entire inner query tree, and build a hash-table lookup. This is the
// Building phase. Then for the first call and all subsequent calls to MoveNext, we will
// incrementally perform the Probing phase. We'll keep getting elements from the outer
// data source, looking into the hash-table we built, and enumerating the full results.
//
// This routine supports both inner and outer (group) joins. An outer join will yield a
// (possibly empty) list of matching elements from the inner instead of one-at-a-time,
// as we do for inner joins.
//
internal override bool MoveNext(ref TOutput currentElement, ref TOutputKey currentKey)
{
Debug.Assert(_resultSelector != null, "expected a compiled result selector");
Debug.Assert(_leftSource != null);
Debug.Assert(_rightLookupBuilder != null);
// BUILD phase: If we haven't built the hash-table yet, create that first.
Mutables mutables = _mutables;
if (mutables == null)
{
mutables = _mutables = new Mutables();
mutables._rightHashLookup = _rightLookupBuilder.BuildHashLookup(_cancellationToken);
}
// PROBE phase: So long as the source has a next element, return the match.
ListChunk <Pair <TRightInput, TRightKey> > currentRightChunk = mutables._currentRightMatches;
if (currentRightChunk != null && mutables._currentRightMatchesIndex == currentRightChunk.Count)
{
mutables._currentRightMatches = currentRightChunk.Next;
mutables._currentRightMatchesIndex = 0;
}
if (mutables._currentRightMatches == null)
{
// We have to look up the next list of matches in the hash-table.
Pair <TLeftInput, THashKey> leftPair = default(Pair <TLeftInput, THashKey>);
TLeftKey leftKey = default(TLeftKey);
while (_leftSource.MoveNext(ref leftPair, ref leftKey))
{
if ((mutables._outputLoopCount++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// Find the match in the hash table.
HashLookupValueList <TRightInput, TRightKey> matchValue = default(HashLookupValueList <TRightInput, TRightKey>);
TLeftInput leftElement = leftPair.First;
THashKey leftHashKey = leftPair.Second;
// Ignore null keys.
if (leftHashKey != null)
{
if (mutables._rightHashLookup.TryGetValue(leftHashKey, ref matchValue))
{
// We found a new match. We remember the list in case there are multiple
// values under this same key -- the next iteration will pick them up.
mutables._currentRightMatches = matchValue.Tail;
Debug.Assert(mutables._currentRightMatches == null || mutables._currentRightMatches.Count > 0,
"we were expecting that the list would be either null or empty");
mutables._currentRightMatchesIndex = 0;
// Yield the value.
currentElement = _resultSelector(leftElement, matchValue.Head.First);
currentKey = _outputKeyBuilder.Combine(leftKey, matchValue.Head.Second);
// If there is a list of matches, remember the left values for next time.
if (matchValue.Tail != null)
{
mutables._currentLeft = leftElement;
mutables._currentLeftKey = leftKey;
}
return(true);
}
}
}
// If we've reached the end of the data source, we're done.
return(false);
}
// Produce the next element.
Debug.Assert(mutables._currentRightMatches != null);
Debug.Assert(0 <= mutables._currentRightMatchesIndex && mutables._currentRightMatchesIndex < mutables._currentRightMatches.Count);
Pair <TRightInput, TRightKey> rightMatch = mutables._currentRightMatches._chunk[mutables._currentRightMatchesIndex];
currentElement = _resultSelector(mutables._currentLeft, rightMatch.First);
currentKey = _outputKeyBuilder.Combine(mutables._currentLeftKey, rightMatch.Second);
mutables._currentRightMatchesIndex++;
return(true);
}
internal override bool MoveNext(ref TOutput currentElement, ref TLeftKey currentKey)
{
Mutables <TLeftInput, TLeftKey, TRightInput, THashKey, TOutput> mutables = this.m_mutables;
if (mutables == null)
{
mutables = this.m_mutables = new Mutables <TLeftInput, TLeftKey, TRightInput, THashKey, TOutput>();
mutables.m_rightHashLookup = new HashLookup <THashKey, Pair <TRightInput, ListChunk <TRightInput> > >(this.m_keyComparer);
Pair <TRightInput, THashKey> pair = new Pair <TRightInput, THashKey>();
int num = 0;
int num2 = 0;
while (this.m_rightSource.MoveNext(ref pair, ref num))
{
if ((num2++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(this.m_cancellationToken);
}
TRightInput first = pair.First;
THashKey second = pair.Second;
if (second != null)
{
Pair <TRightInput, ListChunk <TRightInput> > pair2 = new Pair <TRightInput, ListChunk <TRightInput> >();
if (!mutables.m_rightHashLookup.TryGetValue(second, ref pair2))
{
pair2 = new Pair <TRightInput, ListChunk <TRightInput> >(first, null);
if (this.m_groupResultSelector != null)
{
pair2.Second = new ListChunk <TRightInput>(2);
pair2.Second.Add(first);
}
mutables.m_rightHashLookup.Add(second, pair2);
}
else
{
if (pair2.Second == null)
{
pair2.Second = new ListChunk <TRightInput>(2);
mutables.m_rightHashLookup[second] = pair2;
}
pair2.Second.Add(first);
}
}
}
}
ListChunk <TRightInput> currentRightMatches = mutables.m_currentRightMatches;
if ((currentRightMatches != null) && (mutables.m_currentRightMatchesIndex == currentRightMatches.Count))
{
currentRightMatches = mutables.m_currentRightMatches = currentRightMatches.Next;
mutables.m_currentRightMatchesIndex = 0;
}
if (mutables.m_currentRightMatches == null)
{
Pair <TLeftInput, THashKey> pair3 = new Pair <TLeftInput, THashKey>();
TLeftKey local3 = default(TLeftKey);
while (this.m_leftSource.MoveNext(ref pair3, ref local3))
{
if ((mutables.m_outputLoopCount++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(this.m_cancellationToken);
}
Pair <TRightInput, ListChunk <TRightInput> > pair4 = new Pair <TRightInput, ListChunk <TRightInput> >();
TLeftInput local4 = pair3.First;
THashKey key = pair3.Second;
if (((key != null) && mutables.m_rightHashLookup.TryGetValue(key, ref pair4)) && (this.m_singleResultSelector != null))
{
mutables.m_currentRightMatches = pair4.Second;
mutables.m_currentRightMatchesIndex = 0;
currentElement = this.m_singleResultSelector(local4, pair4.First);
currentKey = local3;
if (pair4.Second != null)
{
mutables.m_currentLeft = local4;
mutables.m_currentLeftKey = local3;
}
return(true);
}
if (this.m_groupResultSelector != null)
{
IEnumerable <TRightInput> enumerable = pair4.Second;
if (enumerable == null)
{
enumerable = (IEnumerable <TRightInput>)ParallelEnumerable.Empty <TRightInput>();
}
currentElement = this.m_groupResultSelector(local4, enumerable);
currentKey = local3;
return(true);
}
}
return(false);
}
currentElement = this.m_singleResultSelector(mutables.m_currentLeft, mutables.m_currentRightMatches.m_chunk[mutables.m_currentRightMatchesIndex]);
currentKey = mutables.m_currentLeftKey;
mutables.m_currentRightMatchesIndex++;
return(true);
}
// constructor used to build a new list.
internal HashLookupValueList(TElement firstValue, TOrderKey firstOrderKey)
{
_head = CreatePair(firstValue, firstOrderKey);
_tail = null;
}
protected override Pair <IEnumerable <TElement>, int> CreateValuePair(ListChunk <TElement> baseValue)
{
return(new Pair <IEnumerable <TElement>, int>(baseValue, OrderKey));
}
//---------------------------------------------------------------------------------------
// Called when this enumerator is first enumerated; it must walk through the source
// and redistribute elements to their slot in the exchange matrix.
//
private void EnumerateAndRedistributeElements()
{
Mutables mutables = m_mutables;
Contract.Assert(mutables != null);
ListChunk <Pair <TInputOutput, THashKey> >[] privateBuffers = new ListChunk <Pair <TInputOutput, THashKey> > [m_partitionCount];
ListChunk <TOrderKey>[] privateKeyBuffers = new ListChunk <TOrderKey> [m_partitionCount];
TInputOutput element = default(TInputOutput);
TOrderKey key = default(TOrderKey);
int loopCount = 0;
while (m_source.MoveNext(ref element, ref key))
{
if ((loopCount++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
// Calculate the element's destination partition index, placing it into the
// appropriate buffer from which partitions will later enumerate.
int destinationIndex;
THashKey elementHashKey = default(THashKey);
if (m_keySelector != null)
{
elementHashKey = m_keySelector(element);
destinationIndex = m_repartitionStream.GetHashCode(elementHashKey) % m_partitionCount;
}
else
{
Contract.Assert(typeof(THashKey) == typeof(NoKeyMemoizationRequired));
destinationIndex = m_repartitionStream.GetHashCode(element) % m_partitionCount;
}
Contract.Assert(0 <= destinationIndex && destinationIndex < m_partitionCount,
"destination partition outside of the legal range of partitions");
// Get the buffer for the destnation partition, lazily allocating if needed. We maintain
// this list in our own private cache so that we avoid accessing shared memory locations
// too much. In the original implementation, we'd access the buffer in the matrix ([N,M],
// where N is the current partition and M is the destination), but some rudimentary
// performance profiling indicates copying at the end performs better.
ListChunk <Pair <TInputOutput, THashKey> > buffer = privateBuffers[destinationIndex];
ListChunk <TOrderKey> keyBuffer = privateKeyBuffers[destinationIndex];
if (buffer == null)
{
const int INITIAL_PRIVATE_BUFFER_SIZE = 128;
Contract.Assert(keyBuffer == null);
privateBuffers[destinationIndex] = buffer = new ListChunk <Pair <TInputOutput, THashKey> >(INITIAL_PRIVATE_BUFFER_SIZE);
privateKeyBuffers[destinationIndex] = keyBuffer = new ListChunk <TOrderKey>(INITIAL_PRIVATE_BUFFER_SIZE);
}
buffer.Add(new Pair <TInputOutput, THashKey>(element, elementHashKey));
keyBuffer.Add(key);
}
// Copy the local buffers to the shared space and then signal to other threads that
// we are done. We can then immediately move on to enumerating the elements we found
// for the current partition before waiting at the barrier. If we found a lot, we will
// hopefully never have to physically wait.
for (int i = 0; i < m_partitionCount; i++)
{
m_valueExchangeMatrix[m_partitionIndex, i] = privateBuffers[i];
m_keyExchangeMatrix[m_partitionIndex, i] = privateKeyBuffers[i];
}
m_barrier.Signal();
// Begin at our own buffer.
mutables.m_currentBufferIndex = m_partitionIndex;
mutables.m_currentBuffer = privateBuffers[m_partitionIndex];
mutables.m_currentKeyBuffer = privateKeyBuffers[m_partitionIndex];
mutables.m_currentIndex = ENUMERATION_NOT_STARTED;
}
//---------------------------------------------------------------------------------------
// MoveNext implements all the hash-join logic noted earlier. When it is called first, it
// will execute the entire inner query tree, and build a hash-table lookup. This is the
// Building phase. Then for the first call and all subsequent calls to MoveNext, we will
// incrementally perform the Probing phase. We'll keep getting elements from the outer
// data source, looking into the hash-table we built, and enumerating the full results.
//
// This routine supports both inner and outer (group) joins. An outer join will yield a
// (possibly empty) list of matching elements from the inner instead of one-at-a-time,
// as we do for inner joins.
//
internal override bool MoveNext(ref TOutput currentElement, ref TLeftKey currentKey)
{
Contract.Assert(_singleResultSelector != null || _groupResultSelector != null, "expected a compiled result selector");
Contract.Assert(_leftSource != null);
Contract.Assert(_rightSource != null);
// BUILD phase: If we haven't built the hash-table yet, create that first.
Mutables mutables = _mutables;
if (mutables == null)
{
mutables = _mutables = new Mutables();
#if DEBUG
int hashLookupCount = 0;
int hashKeyCollisions = 0;
#endif
mutables._rightHashLookup = new HashLookup <THashKey, Pair>(_keyComparer);
Pair rightPair = new Pair(default(TRightInput), default(THashKey));
int rightKeyUnused = default(int);
int i = 0;
while (_rightSource.MoveNext(ref rightPair, ref rightKeyUnused))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
TRightInput rightElement = (TRightInput)rightPair.First;
THashKey rightHashKey = (THashKey)rightPair.Second;
// We ignore null keys.
if (rightHashKey != null)
{
#if DEBUG
hashLookupCount++;
#endif
// See if we've already stored an element under the current key. If not, we
// lazily allocate a pair to hold the elements mapping to the same key.
const int INITIAL_CHUNK_SIZE = 2;
Pair currentValue = new Pair(default(TRightInput), default(ListChunk <TRightInput>));
if (!mutables._rightHashLookup.TryGetValue(rightHashKey, ref currentValue))
{
currentValue = new Pair(rightElement, null);
if (_groupResultSelector != null)
{
// For group joins, we also add the element to the list. This makes
// it easier later to yield the list as-is.
currentValue.Second = new ListChunk <TRightInput>(INITIAL_CHUNK_SIZE);
((ListChunk <TRightInput>)currentValue.Second).Add((TRightInput)rightElement);
}
mutables._rightHashLookup.Add(rightHashKey, currentValue);
}
else
{
if (currentValue.Second == null)
{
// Lazily allocate a list to hold all but the 1st value. We need to
// re-store this element because the pair is a value type.
currentValue.Second = new ListChunk <TRightInput>(INITIAL_CHUNK_SIZE);
mutables._rightHashLookup[rightHashKey] = currentValue;
}
((ListChunk <TRightInput>)currentValue.Second).Add((TRightInput)rightElement);
#if DEBUG
hashKeyCollisions++;
#endif
}
}
}
#if DEBUG
TraceHelpers.TraceInfo("ParallelJoinQueryOperator::MoveNext - built hash table [count = {0}, collisions = {1}]",
hashLookupCount, hashKeyCollisions);
#endif
}
// PROBE phase: So long as the source has a next element, return the match.
ListChunk <TRightInput> currentRightChunk = mutables._currentRightMatches;
if (currentRightChunk != null && mutables._currentRightMatchesIndex == currentRightChunk.Count)
{
currentRightChunk = mutables._currentRightMatches = currentRightChunk.Next;
mutables._currentRightMatchesIndex = 0;
}
if (mutables._currentRightMatches == null)
{
// We have to look up the next list of matches in the hash-table.
Pair leftPair = new Pair(default(TLeftInput), default(THashKey));
TLeftKey leftKey = default(TLeftKey);
while (_leftSource.MoveNext(ref leftPair, ref leftKey))
{
if ((mutables._outputLoopCount++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// Find the match in the hash table.
Pair matchValue = new Pair(default(TRightInput), default(ListChunk <TRightInput>));
TLeftInput leftElement = (TLeftInput)leftPair.First;
THashKey leftHashKey = (THashKey)leftPair.Second;
// Ignore null keys.
if (leftHashKey != null)
{
if (mutables._rightHashLookup.TryGetValue(leftHashKey, ref matchValue))
{
// We found a new match. For inner joins, we remember the list in case
// there are multiple value under this same key -- the next iteration will pick
// them up. For outer joins, we will use the list momentarily.
if (_singleResultSelector != null)
{
mutables._currentRightMatches = (ListChunk <TRightInput>)matchValue.Second;
Contract.Assert(mutables._currentRightMatches == null || mutables._currentRightMatches.Count > 0,
"we were expecting that the list would be either null or empty");
mutables._currentRightMatchesIndex = 0;
// Yield the value.
currentElement = _singleResultSelector(leftElement, (TRightInput)matchValue.First);
currentKey = leftKey;
// If there is a list of matches, remember the left values for next time.
if (matchValue.Second != null)
{
mutables._currentLeft = leftElement;
mutables._currentLeftKey = leftKey;
}
return(true);
}
}
}
// For outer joins, we always yield a result.
if (_groupResultSelector != null)
{
// Grab the matches, or create an empty list if there are none.
IEnumerable <TRightInput> matches = (ListChunk <TRightInput>)matchValue.Second;
if (matches == null)
{
matches = ParallelEnumerable.Empty <TRightInput>();
}
// Generate the current value.
currentElement = _groupResultSelector(leftElement, matches);
currentKey = leftKey;
return(true);
}
}
// If we've reached the end of the data source, we're done.
return(false);
}
// Produce the next element and increment our index within the matches.
Contract.Assert(_singleResultSelector != null);
Contract.Assert(mutables._currentRightMatches != null);
Contract.Assert(0 <= mutables._currentRightMatchesIndex && mutables._currentRightMatchesIndex < mutables._currentRightMatches.Count);
currentElement = _singleResultSelector(
mutables._currentLeft, mutables._currentRightMatches._chunk[mutables._currentRightMatchesIndex]);
currentKey = mutables._currentLeftKey;
mutables._currentRightMatchesIndex++;
return(true);
}
