public override void Open()
{
_build.Open();
_probe.Open();
BuildHashtable();
_entry = null;
_entryEnumerator = null;
_currentPhase = Phase.ProduceMatch;
_probeMatched = true;
}
private void AddToHashtable(object keyValue, object[] values)
{
HashMatchEntry entry;
_hashTable.TryGetValue(keyValue, out entry);
if (entry == null)
{
entry = new HashMatchEntry();
}
else
{
var newEntry = new HashMatchEntry {
Next = entry
};
entry = newEntry;
}
entry.RowValues = values;
_hashTable[keyValue] = entry;
}
public override bool Read()
{
switch (_currentPhase)
{
case Phase.ProduceMatch:
{
var matchFound = false;
_rowBuffer.SetProbe(_probe.RowBuffer);
while (!matchFound)
{
if (_entry != null)
{
_entry = _entry.Next;
}
if (_entry == null)
{
// All rows having the same key value are exhausted.
if (!_probeMatched && (_logicalOperator == BoundHashMatchOperator.FullOuter ||
_logicalOperator == BoundHashMatchOperator.RightOuter))
{
_probeMatched = true;
_rowBuffer.SetBuild(null);
return(true);
}
// Read next row from probe input.
if (!_probe.Read())
{
// The probe input is exhausted. If we have a full outer or left outer
// join we are not finished. We have to return all rows from the build
// input that have not been matched with the probe input.
if (_logicalOperator == BoundHashMatchOperator.FullOuter ||
_logicalOperator == BoundHashMatchOperator.LeftOuter)
{
_currentPhase = Phase.ReturnUnmatchedRowsFromBuildInput;
_entry = null;
goto case Phase.ReturnUnmatchedRowsFromBuildInput;
}
return(false);
}
// Get probe value
_probeMatched = false;
var probeValue = _probe.RowBuffer[_probeIndex];
// Seek first occurence of probe value
if (probeValue != null)
{
_hashTable.TryGetValue(probeValue, out _entry);
}
}
if (_entry != null)
{
_rowBuffer.SetBuild(_entry);
if (_remainder())
{
_entry.Matched = true;
matchFound = true;
_probeMatched = true;
}
}
}
return(true);
}
case Phase.ReturnUnmatchedRowsFromBuildInput:
{
var unmatchedFound = false;
_rowBuffer.SetProbe(null);
while (!unmatchedFound)
{
if (_entry != null)
{
_entry = _entry.Next;
}
if (_entry == null)
{
if (_entryEnumerator == null)
{
_entryEnumerator = _hashTable.Values.GetEnumerator();
}
// All rows having the same key value are exhausted.
// Read next key from build input.
if (!_entryEnumerator.MoveNext())
{
// We have read all keys. So we are finished.
return(false);
}
_entry = _entryEnumerator.Current;
}
unmatchedFound = !_entry.Matched;
}
_rowBuffer.SetBuild(_entry);
return(true);
}
default:
throw ExceptionBuilder.UnexpectedValue(_currentPhase);
}
}
public void SetBuild(HashMatchEntry entry)
{
_buildEntry.Entry = entry;
_build.ActiveRowBuffer = entry == null ? (RowBuffer)_buildNull : _buildEntry;
}
