public bool RedistributeFromLeft(ulong txnId, ILeafNode leftNode)
{
var left = leftNode as LeafNode;
if (left == null)
{
throw new ArgumentException("Expected a LeafNode instance", "leftNode");
}
int copyCount = (KeyCount + left.KeyCount) / 2 - KeyCount;
if (copyCount > 0)
{
EnsureWriteable(txnId);
RightShift(copyCount);
// Copy keys and data from left node
int keyOffset = KeyOffset(left.KeyCount - copyCount);
_page.SetData(left.GetData(), keyOffset, KeyOffset(0), copyCount * _config.KeySize);
if (_config.ValueSize > 0)
{
int valueOffset = ValueOffset(left.KeyCount - copyCount);
_page.SetData(left.GetData(), valueOffset, ValueOffset(0), copyCount * _config.ValueSize);
}
KeyCount += copyCount;
left.KeyCount -= copyCount;
return(true);
}
return(false);
}
public bool RedistributeFromRight(ulong txnId, ILeafNode rightNode)
{
var right = rightNode as LeafNode;
if (right == null)
{
throw new ArgumentException("Expected a LeafNode instance", "rightNode");
}
int copyCount = (KeyCount + rightNode.KeyCount) / 2 - KeyCount;
if (copyCount > 0)
{
EnsureWriteable(txnId);
// Copy keys and data from right
_page.SetData(right.GetData(), BPlusTreeConfiguration.LeafNodeHeaderSize,
KeyOffset(KeyCount), copyCount * _config.KeySize);
if (_config.ValueSize > 0)
{
_page.SetData(right.GetData(), _config.LeafDataStartOffset,
ValueOffset(KeyCount), copyCount * _config.ValueSize);
}
// Shift up the remaining keys in the right
right.LeftShift(copyCount);
// Update my key count
KeyCount += copyCount;
return(true);
}
return(false);
}
private IEnumerable <KeyValuePair <byte[], ulong> > MakeLeafNodes(ulong txnId, IEnumerator <KeyValuePair <byte[], byte[]> > orderedValues, BrightstarProfiler profiler = null)
{
ILeafNode prevNode = MakeLeafNode(txnId, orderedValues.Next(_leafLoadFactor));
if (prevNode.KeyCount < _leafLoadFactor)
{
// There were only enough values to fill a single leaf node
yield return(WriteNode(txnId, prevNode, profiler));
yield break;
}
ILeafNode nextNode = MakeLeafNode(txnId, orderedValues.Next(_leafLoadFactor));
do
{
if (nextNode.KeyCount >= _config.LeafSplitIndex)
{
yield return(WriteNode(txnId, prevNode, profiler));
}
else
{
// Final leaf node needs to share some values from the previous node we created
nextNode.RedistributeFromLeft(txnId, prevNode);
yield return(WriteNode(txnId, prevNode, profiler));
}
prevNode = nextNode;
var nextKeys = orderedValues.Next(_leafLoadFactor).ToList();
nextNode = nextKeys.Count > 0 ? MakeLeafNode(txnId, nextKeys) : null;
} while (nextNode != null);
yield return(WriteNode(txnId, prevNode, profiler));
}
private KeyValuePair<byte[], ulong> WriteNode(ulong txnId, ILeafNode node, BrightstarProfiler profiler = null)
{
//_pageStore.Write(txnId, node.PageId, node.GetData(), profiler: profiler);
return new KeyValuePair<byte[], ulong>(node.LeftmostKey, node.PageId);
}
private KeyValuePair <byte[], ulong> WriteNode(ulong txnId, ILeafNode node, BrightstarProfiler profiler = null)
{
//_pageStore.Write(txnId, node.PageId, node.GetData(), profiler: profiler);
return(new KeyValuePair <byte[], ulong>(node.LeftmostKey, node.PageId));
}
private Tuple <Expression, IEnumerable <Expression> > CreateIndexExpression(ILeafNode <Expression> leaf, List <int> indexes)
{
var indexExpressions = indexes.Select(i => Expression.Constant(i, TypeSystem.Int));
return(Tuple.Create <Expression, IEnumerable <Expression> >(leaf.Value, indexExpressions.ToList()));
}
private void Delete(ulong txnId, IInternalNode parentInternalNode, byte[] key, out bool underAllocation, BrightstarProfiler profiler)
{
if (parentInternalNode.RightmostKey == null)
{
throw new ArgumentException("Parent node right key is null");
}
var childNodeId = parentInternalNode.GetChildNodeId(key);
var childNode = GetNode(childNodeId, profiler);
if (childNode is ILeafNode)
{
var childLeafNode = childNode as ILeafNode;
// Delete the key and mark the node as updated. This may update the child node id
childLeafNode.Delete(txnId, key);
MarkDirty(txnId, childLeafNode, profiler);
if (childLeafNode.PageId != childNodeId)
{
parentInternalNode.UpdateChildPointer(txnId, childNodeId, childLeafNode.PageId);
childNodeId = childLeafNode.PageId;
}
if (childLeafNode.NeedsJoin)
{
ulong leftSiblingId, rightSiblingId;
ILeafNode leftSibling = null, rightSibling = null;
bool hasLeftSibling = parentInternalNode.GetLeftSibling(childNodeId, out leftSiblingId);
if (hasLeftSibling)
{
leftSibling = GetNode(leftSiblingId, profiler) as ILeafNode;
if (childLeafNode.RedistributeFromLeft(txnId, leftSibling))
{
parentInternalNode.SetLeftKey(txnId, childLeafNode.PageId, childLeafNode.LeftmostKey);
MarkDirty(txnId, parentInternalNode, profiler);
MarkDirty(txnId, leftSibling, null);
parentInternalNode.UpdateChildPointer(txnId, leftSiblingId, leftSibling.PageId);
underAllocation = false;
return;
}
}
bool hasRightSibling = parentInternalNode.GetRightSiblingId(childNodeId, out rightSiblingId);
if (hasRightSibling)
{
rightSibling = GetNode(rightSiblingId, profiler) as ILeafNode;
#if DEBUG
if (rightSibling.LeftmostKey.Compare(childLeafNode.RightmostKey) <= 0)
{
throw new Exception("Right-hand sibling has a left key lower than this nodes right key.");
}
#endif
if (childLeafNode.RedistributeFromRight(txnId, rightSibling))
{
MarkDirty(txnId, rightSibling, profiler);
parentInternalNode.UpdateChildPointer(txnId, rightSiblingId, rightSibling.PageId);
parentInternalNode.SetLeftKey(txnId, rightSibling.PageId, rightSibling.LeftmostKey);
MarkDirty(txnId, parentInternalNode, profiler);
underAllocation = false;
return;
}
}
if (hasLeftSibling && childLeafNode.Merge(txnId, leftSibling))
{
parentInternalNode.RemoveChildPointer(txnId, leftSiblingId);
parentInternalNode.SetLeftKey(txnId, childLeafNode.PageId, childLeafNode.LeftmostKey);
MarkDirty(txnId, parentInternalNode, profiler);
underAllocation = parentInternalNode.NeedJoin;
return;
}
if (hasRightSibling && childLeafNode.Merge(txnId, rightSibling))
{
byte[] nodeKey = parentInternalNode.RemoveChildPointer(txnId, rightSiblingId);
if (nodeKey == null)
{
// We merged in the right-most node, so we need to generate a key
nodeKey = new byte[_config.KeySize];
Array.Copy(rightSibling.RightmostKey, nodeKey, _config.KeySize);
ByteArrayHelper.Increment(nodeKey);
}
parentInternalNode.SetKey(txnId, childLeafNode.PageId, nodeKey);
MarkDirty(txnId, parentInternalNode, profiler);
underAllocation = parentInternalNode.NeedJoin;
return;
}
}
underAllocation = false;
return;
}
if (childNode is IInternalNode)
{
bool childUnderAllocated;
var childInternalNode = childNode as IInternalNode;
Delete(txnId, childInternalNode, key, out childUnderAllocated, profiler);
if (childInternalNode.PageId != childNodeId)
{
// Child node page changed
parentInternalNode.UpdateChildPointer(txnId, childNodeId, childInternalNode.PageId);
MarkDirty(txnId, parentInternalNode, profiler);
childNodeId = childInternalNode.PageId;
}
if (childUnderAllocated)
{
IInternalNode leftSibling = null, rightSibling = null;
ulong leftSiblingId, rightSiblingId;
// Redistribute values from left-hand sibling
bool hasLeftSibling = parentInternalNode.GetLeftSibling(childNodeId, out leftSiblingId);
if (hasLeftSibling)
{
leftSibling = GetNode(leftSiblingId, profiler) as IInternalNode;
byte[] joinKey = parentInternalNode.GetKey(leftSiblingId);
var newJoinKey = new byte[_config.KeySize];
if (childInternalNode.RedistributeFromLeft(txnId, leftSibling, joinKey, newJoinKey))
{
MarkDirty(txnId, leftSibling, profiler);
parentInternalNode.UpdateChildPointer(txnId, leftSiblingId, leftSibling.PageId);
parentInternalNode.SetKey(txnId, leftSibling.PageId, newJoinKey);
MarkDirty(txnId, parentInternalNode, profiler);
underAllocation = false;
return;
}
}
// Redistribute values from right-hand sibling
bool hasRightSibling = parentInternalNode.GetRightSiblingId(childNodeId, out rightSiblingId);
if (hasRightSibling)
{
rightSibling = GetNode(rightSiblingId, profiler) as IInternalNode;
byte[] joinKey = parentInternalNode.GetKey(childInternalNode.PageId);
byte[] newJoinKey = new byte[_config.KeySize];
if (childInternalNode.RedistributeFromRight(txnId, rightSibling, joinKey, newJoinKey))
{
MarkDirty(txnId, rightSibling, profiler);
parentInternalNode.UpdateChildPointer(txnId, rightSiblingId, rightSibling.PageId);
// parentInternalNode.SetKey(rightSibling.PageId, newJoinKey); -- think this is wrong should be:
parentInternalNode.SetKey(txnId, childInternalNode.PageId, newJoinKey);
MarkDirty(txnId, parentInternalNode, profiler);
underAllocation = false;
return;
}
}
// Merge with left-hand sibling
if (hasLeftSibling)
{
// Attempt to merge child node into its left sibling
var joinKey = parentInternalNode.GetKey(leftSibling.PageId);
var mergedNodeKey = parentInternalNode.GetKey(childInternalNode.PageId);
if (mergedNodeKey == null)
{
mergedNodeKey = new byte[_config.KeySize];
Array.Copy(childInternalNode.RightmostKey, mergedNodeKey, _config.KeySize);
ByteArrayHelper.Increment(mergedNodeKey);
}
if (leftSibling.Merge(txnId, childInternalNode, joinKey))
{
MarkDirty(txnId, leftSibling, profiler);
if (leftSibling.PageId != leftSiblingId)
{
// We have a new page id (append-only stores will do this)
parentInternalNode.UpdateChildPointer(txnId, leftSiblingId, leftSibling.PageId);
}
parentInternalNode.RemoveChildPointer(txnId, childInternalNode.PageId);
parentInternalNode.SetKey(txnId, leftSibling.PageId, mergedNodeKey);
MarkDirty(txnId, parentInternalNode, profiler);
underAllocation = parentInternalNode.NeedJoin;
return;
}
}
// Merge with right-hand sibling
if (hasRightSibling)
{
// Attempt to merge right sibling into child node
var joinKey = parentInternalNode.GetKey(childNodeId);
if (childInternalNode.Merge(txnId, rightSibling, joinKey))
{
MarkDirty(txnId, childInternalNode, profiler);
var nodeKey = parentInternalNode.RemoveChildPointer(txnId, rightSiblingId);
if (childInternalNode.PageId != childNodeId)
{
// We have a new page id for the child node (append-only stores will do this)
parentInternalNode.UpdateChildPointer(txnId, childNodeId, childInternalNode.PageId);
}
if (nodeKey == null)
{
// We merged in the right-most node, so we need to generate a key
nodeKey = new byte[_config.KeySize];
Array.Copy(rightSibling.RightmostKey, nodeKey, _config.KeySize);
ByteArrayHelper.Increment(nodeKey);
}
parentInternalNode.SetKey(txnId, childInternalNode.PageId, nodeKey);
MarkDirty(txnId, parentInternalNode, profiler);
underAllocation = parentInternalNode.NeedJoin;
return;
}
}
throw new NotImplementedException(
"Not yet implemented handling for internal node becoming under allocated");
}
underAllocation = false;
}
else
{
throw new BrightstarInternalException(String.Format("Unrecognised B+ Tree node class : {0}",
childNode.GetType()));
}
}
public bool RedistributeFromRight(ulong txnId, ILeafNode rightNode)
{
var right = rightNode as LeafNode;
if (right == null) throw new ArgumentException("Expected a LeafNode instance", "rightNode");
int copyCount = (KeyCount + rightNode.KeyCount)/2 - KeyCount;
if (copyCount > 0)
{
EnsureWriteable(txnId);
// Copy keys and data from right
_page.SetData(right.GetData(), BPlusTreeConfiguration.LeafNodeHeaderSize,
KeyOffset(KeyCount), copyCount*_config.KeySize);
if (_config.ValueSize > 0)
{
_page.SetData(right.GetData(), _config.LeafDataStartOffset,
ValueOffset(KeyCount), copyCount * _config.ValueSize);
}
// Shift up the remaining keys in the right
right.LeftShift(copyCount);
// Update my key count
KeyCount += copyCount;
return true;
}
return false;
}
public bool RedistributeFromLeft(ulong txnId, ILeafNode leftNode)
{
var left = leftNode as LeafNode;
if (left == null) throw new ArgumentException("Expected a LeafNode instance", "leftNode");
int copyCount = (KeyCount + left.KeyCount)/2 - KeyCount;
if (copyCount > 0)
{
EnsureWriteable(txnId);
RightShift(copyCount);
// Copy keys and data from left node
int keyOffset = KeyOffset(left.KeyCount - copyCount);
_page.SetData(left.GetData(), keyOffset, KeyOffset(0), copyCount*_config.KeySize);
if (_config.ValueSize > 0)
{
int valueOffset = ValueOffset(left.KeyCount - copyCount);
_page.SetData(left.GetData(), valueOffset, ValueOffset(0), copyCount*_config.ValueSize);
}
KeyCount += copyCount;
left.KeyCount -= copyCount;
return true;
}
return false;
}
private Tuple<Expression, IEnumerable<Expression>> CreateIndexExpression(ILeafNode<Expression> leaf, List<int> indexes) {
var indexExpressions = indexes.Select(i => Expression.Constant(i, TypeSystem.Int));
return Tuple.Create<Expression, IEnumerable<Expression>>(leaf.Value, indexExpressions.ToList());
}
