public BTree(uint topSid, SegmentManager sm, IKey keyFactory)
{
this.m_top_sid = topSid;
this.m_sgManager = sm;
this.m_keyFactory = keyFactory;
this.m_nodeFactory = new BNode();
}
/// <summary>
/// Create the internal storage for the dbFile.
/// Note:
/// 1. a helper file for segment managment b-tree is also created if this database file
/// does not exist.
/// </summary>
/// <param name="dbFile"></param>
public ObjectStore(string dbFileName)
{
m_dbFile = new DiskFile(dbFileName);
m_indexFile = new DiskFile(dbFileName+".idx");
m_indexPageManager = new memSegmentManager(m_indexFile);
if (m_indexPageManager.Header.InitializeNeeded)
{
m_indexPageManager.Header.NextSegmentId = 0;
m_indexPageManager.Header.NextObjectId = 0;
m_indexPageManager.Header.NextClassId = 0;
//initialize the segment b-tree's top node id
OOD.Imp.Storage.BNode segTreeTop = new OOD.Imp.Storage.BNode();
m_indexPageManager.GetNewSegment(segTreeTop);
segTreeTop.SetOrder(m_segTreeNodeOrder);
segTreeTop.Leaf = true;
m_indexPageManager.Header.SegmentTreeTopNodeSId = segTreeTop.SegmentID;
//initialize the space b-tree's top node id
BNode spaceTreeTop = new BNode();
m_indexPageManager.GetNewSegment(spaceTreeTop);
spaceTreeTop.SetOrder(m_spaceTreeNodeOrder);
spaceTreeTop.Leaf = true;
m_indexPageManager.Header.FreeSpaceTreeTopNodeSId = spaceTreeTop.SegmentID;
}
m_segmentIndexTree = new SegTree(m_indexPageManager.Header.SegmentTreeTopNodeSId, m_indexPageManager);
m_spaceIndexTree = new SpaceTree(m_indexPageManager.Header.FreeSpaceTreeTopNodeSId, m_indexPageManager, m_dbFile);
m_dbSegmentManager = new dbSegmentManager(
m_indexPageManager.Header.NextSegmentId,
m_segmentIndexTree,
m_spaceIndexTree,
m_dbFile);
if (m_indexPageManager.Header.InitializeNeeded)
{
BNode catalogTop = new BNode();
m_dbSegmentManager.GetNewSegment(catalogTop);
catalogTop.SetOrder(m_catalogTreeNodeOrder);
catalogTop.Leaf = true;
m_indexPageManager.Header.CatalogTreeTopNodeSId = catalogTop.SegmentID;
}
m_catalogTree = new CatalogTree(
m_indexPageManager.Header.CatalogTreeTopNodeSId,
m_dbSegmentManager,
m_indexPageManager.Header.NextClassId);
m_classCache = new LRUHashtable(m_cache_size, m_classCacheLimit);
m_objectTreeCache = new LRUHashtable(m_cache_size, m_objectTreeCacheLimit);
//bring top node's segment tree, space tree, catalog tree into cache, they will be needed anyway
if (!m_indexPageManager.Header.InitializeNeeded)
{
m_indexPageManager.GetSegment(m_segmentIndexTree.TopNodSegId, new BNode(), new KSegId());
m_indexPageManager.GetSegment(m_spaceIndexTree.TopNodeSId, new BNode(), new KOffset());
m_dbSegmentManager.GetSegment(m_catalogTree.TopNodeSId, new BNode(), new KCatalog());
}
}
/* operations regarding class information, scheme */
public bool InsertClassIno(string className, string[] fieldNames, ref uint assignedCId, ref uint topNodeSId)
{
if (m_catalogTree.Search(className) != null)
return false;
//reserve a segment id for this class clustering's top node
BNode classTopSid = new BNode();
m_dbSegmentManager.GetNewSegment(classTopSid);
classTopSid.SetOrder(m_classTreeNodeOrder);
classTopSid.Leaf = true;
topNodeSId = classTopSid.SegmentID;
if (m_catalogTree.Insert(className, fieldNames, classTopSid.SegmentID, ref assignedCId) == false)
throw new OOD.Exception.ProgramLogicError(
this,
"Inserting class information failed.");
return true;
}
public bool MoveNext()
{
m_current_key_no ++;
if (m_current_key_no < m_current_node.KeyNums)
{
m_current = m_current_node.GetKeyAt(m_current_key_no);
}
else
{
//this node is used up, try next one
if (m_to_be_visited.Count >0)
{
m_current_node = (BNode)m_tree.m_sgManager.GetSegment(
(uint)m_to_be_visited.Dequeue(),
m_tree.m_nodeFactory,
m_tree.m_keyFactory);
Debug.Assert(m_current_node.KeyNums>0);
if (!m_current_node.Leaf)
{
for (int i=0; i<=m_current_node.KeyNums; i++)
{
Debug.Assert(m_current_node.GetChildAt(i) >= 0);
m_to_be_visited.Enqueue(m_current_node.GetChildAt(i));
}
}
//locate the current to be the first one in the new node
m_current_key_no = 0;
m_current = m_current_node.GetKeyAt(0);
}
else
m_current = null;
}
return m_current != null;
}
public BTEnumerator(BTree tree)
{
m_tree = tree;
m_to_be_visited = new System.Collections.Queue();
m_current = null;
m_current_node = (BNode) m_tree.m_sgManager.GetSegment(m_tree.m_top_sid, m_tree.m_nodeFactory, m_tree.m_keyFactory);
if (m_current_node.KeyNums >0)
{
for (int i=0; i<=m_current_node.KeyNums; i++)
{
m_to_be_visited.Enqueue(m_current_node.GetChildAt(i));
}
}
m_current_key_no = -1;
}
/// <summary>
/// Given a key, search the node where the key is stored in the tree with root as the root node.
/// </summary>
/// <param name="root"></param>
/// <param name="key"></param>
/// <param name="pos">the location the key is stored in</param>
/// <param name="visisted">all the visisted parent is saved in the stack.</param>
/// <returns></returns>
public BNode FindNode(BNode root, IKey key, ref int pos, System.Collections.Stack visited, System.Collections.Stack via)
{
Debug.Assert(visited != null);
BNode n = root;
pos = -1;
IKey temp = null;
while (!n.Leaf)
{
temp = n.SearchKey(key, ref pos);
if (temp == null)
{
uint nextNodeId = n.GetChildAt(pos);
visited.Push(n);
via.Push(pos);
n = (BNode)m_sgManager.GetSegment(nextNodeId, m_nodeFactory, m_keyFactory);
}
else
return n;
}
//n is leaf
temp = n.SearchKey(key, ref pos);
if (temp == null)
return null;
else
return n;
}
/// <summary>
/// Insert the newKey into this B-tree,
/// </summary>
/// <param name="newKey"></param>
/// <returns></returns>
public bool Insert(IKey newKey)
{
//find the leaf where the newKey should be in
BNode n = m_top;
System.Collections.Stack visited = new System.Collections.Stack();
int pos = -1;
while (!n.Leaf)
{
IKey temp = n.SearchKey(newKey, ref pos);
if (temp == null)
{
uint nextNodeId = n.GetChildAt(pos);
visited.Push(n);
n = (BNode)m_sgManager.GetSegment(nextNodeId, m_nodeFactory, m_keyFactory);
}
else
return false;
}
//now BNode n is the leaf where insert should happen
IKey t_temp = n.SearchKey(newKey, ref pos);
if (t_temp == null)
{
//not exists, go ahead to insert the new key
if (!n.IsFull)
{
n.InsertAtLeaf(newKey, pos);
return true;
}
else
{
//split needed for this node
BNode right = new BNode();
m_sgManager.GetNewSegment(right);
IKey median = null;
n.SplitAtLeaf(newKey, pos, ref median, ref right); //this split is at leaf
bool finished = false;
//now n holds the left half of the items,
//right holds the right half items, median is the middle key
while (!finished)
{
//parent is node middle key will be inserted
BNode parent = (visited.Count >0 ? (BNode)visited.Pop() : null);
if (parent == null)
{
//new top node is needed
BNode new_top = new BNode();
m_sgManager.GetNewSegment(new_top);
new_top.SetOrder(m_top.Order);
new_top.Leaf = false;
new_top.InsertFirstKey(median, n.SegmentID, right.SegmentID);
this.m_top_sid = new_top.SegmentID;
return true;
}
else
{
IKey tt = parent.SearchKey(median, ref pos);
if (tt != null)
return false;
if (!parent.IsFull)
{
parent.InsertAtInternal(median, pos, right.SegmentID);
return true;
}
else
{
//parent is full again
BNode newRight = new BNode();
m_sgManager.GetNewSegment(newRight);
newRight.SetOrder(parent.Order);
newRight.Leaf = parent.Leaf;
//this split will insert median into the parent, then split and new middle key is newMedian
IKey newMedian;
parent.SplitAtInternal(median, pos, right.SegmentID, out newMedian, newRight);
n = parent;
median = newMedian;
right = newRight;
}
}
}
}
}
else
return false;
return false;
}
/// <summary>
/// Distribute one key from left to right
/// </summary>
/// <param name="pos"></param>
/// <param name="left"></param>
/// <param name="right"></param>
public void RedistributeLeft2Right(int pos, BNode left, BNode right)
{
Debug.Assert(pos >=0 && pos < m_keys.Length);
Debug.Assert(m_children[pos] == left.SegmentID);
Debug.Assert(m_children[pos+1] == right.SegmentID);
Debug.Assert(m_keys[pos].CompareTo(left.m_keys[left.m_keyNums-1])>0);
Debug.Assert(m_keys[pos].CompareTo(right.m_keys[right.m_keyNums-1])<0);
Debug.Assert(right.KeyNums < m_order - 1);
//shift everything in right for the new key
for (int i=right.KeyNums; i>0; i--)
{
right.m_keys[i] = right.m_keys[i-1];
right.m_children[i+1] = right.m_children[i];
}
right.m_children[1] = right.m_children[0];
//copy middle key in parent to the first one of right
right.m_keys[0] = m_keys[pos];
right.m_children[0] = left.m_children[left.KeyNums]; //copy last pointer to be the first pointer in new right node
right.m_keyNums++;
//copy the last key in left into parent
m_keys[pos] = left.m_keys[left.m_keyNums-1];
//remove the last key from left
left.m_keyNums--;
this.m_dirty = true;
left.m_dirty = true;
right.m_dirty = true;
}
/// <summary>
/// Note:
/// 1. helper should be the realy key used in the b-tree.
/// </summary>
/// <param name="segmentId"></param>
/// <param name="helper"></param>
/// <param name="bytes"></param>
/// <param name="offset"></param>
/// <param name="count"></param>
public override Segment Deserialize(uint segmentId, object helper, byte[] bytes, int offset, int count)
{
IKey keyFactory = (IKey)helper;
int pos = offset;
short order = OOD.Utility.Bytes.Unpack2(bytes, pos);
BNode result = new BNode(segmentId, order);
pos += 2;
result.m_leaf = (bytes[pos++] == 1);
result.m_keyNums = OOD.Utility.Bytes.Unpack2(bytes, pos);
pos += 2;
for (int i=0; i<result.m_keyNums; i++)
{
int length = OOD.Utility.Bytes.Unpack2(bytes, pos);
pos += 2;
result.m_keys[i] = keyFactory.Deserialize(bytes, pos, length);
pos += length;
}
for (int i=0; i<=result.m_keyNums; i++)
{
result.m_children[i] = OOD.Utility.Bytes.Unpack4U(bytes, pos);
pos += 4;
}
result.m_dirty = false;
return result;
}
/// <summary>
/// Combine the left, right, along with the key in pos of this node into the new one,
/// and keep left, clear right one.
/// </summary>
/// <param name="pos">the location of the connecting key in this node(parent)</param>
/// <param name="left"></param>
/// <param name="right"></param>
public void CombineChildren(int pos, BNode left, BNode right)
{
Debug.Assert(pos >=0 && pos < m_keys.Length);
Debug.Assert(m_children[pos] == left.SegmentID);
Debug.Assert(m_children[pos+1] == right.SegmentID);
Debug.Assert(m_keys[pos].CompareTo(left.m_keys[left.m_keyNums-1])>0);
Debug.Assert(m_keys[pos].CompareTo(right.m_keys[right.m_keyNums-1])<0);
left.m_keys[left.m_keyNums] = m_keys[pos];
left.m_children[left.m_keyNums+1] = right.m_children[0];
left.m_keyNums ++ ;
for (int i=0; i<right.m_keyNums; i++)
{
left.m_keys[left.m_keyNums++] = right.m_keys[i];
left.m_children[left.m_keyNums] = right.m_children[i+1];
}
right.m_keyNums = 0;
//remove pos record in the parent
Remove(pos);
this.m_dirty = true;
left.m_dirty = true;
right.m_dirty = true;
}
/// <summary>
/// Redistribute one from right to left
/// </summary>
/// <param name="pos">pos is pointing the middle connecting key in between the left and right.</param>
/// <param name="left"></param>
/// <param name="right"></param>
public void RedistributeRight2Left(int pos, BNode left, BNode right)
{
Debug.Assert(pos >=0 && pos < m_keys.Length);
Debug.Assert(m_children[pos] == left.SegmentID);
Debug.Assert(m_children[pos+1] == right.SegmentID);
Debug.Assert(m_keys[pos].CompareTo(left.m_keys[left.m_keyNums-1])>0);
Debug.Assert(m_keys[pos].CompareTo(right.m_keys[right.m_keyNums-1])<0);
//copy middle key in parent to tail of left
left.m_keys[left.m_keyNums++] = m_keys[pos];
left.m_children[left.m_keyNums] = right.m_children[0]; //move first pointer in right to be the last in new left
//replace the middle key with the first key in right
m_keys[pos] = right.m_keys[0];
//remove the first key along with the first pointer from right
for (int i=1; i<right.KeyNums; i++)
{
right.m_keys[i-1] = right.m_keys[i];
right.m_children[i-1] = right.m_children[i];
}
right.m_keyNums --;
//move the last one
right.m_children[right.m_keyNums] = right.m_children[right.m_keyNums+1];
this.m_dirty = true;
left.m_dirty = true;
right.m_dirty = true;
}
/// <summary>
/// Split the internal node with the newKey which is trying to insert this internal node
/// </summary>
/// <param name="newKey"></param>
/// <param name="pos"></param>
/// <param name="right"></param>
/// <param name="newMedian"></param>
/// <param name="newRight"></param>
public void SplitAtInternal(IKey newKey, int pos, uint rightSon, out IKey newMedian, BNode newRight)
{
Debug.Assert(this.m_leaf == false);
Debug.Assert(this.IsFull);
IKey[] temp = new IKey[m_order];
uint[] t_pointer = new uint[m_order + 1];
//copy old data into new arrays
Array.Copy(m_keys, 0, temp, 0, m_order-1);
Array.Copy(m_children, 0, t_pointer, 0, m_order);
//shift everything after this key right
for (int i=this.m_keyNums; i>pos; i--)
{
temp[i] = temp[i-1];
t_pointer[i+1] = t_pointer[i];
}
temp[pos] = newKey;
t_pointer[pos+1] = rightSon;
//copy left half back this node
int mid = m_order >> 1;
Array.Copy(temp,0,m_keys,0,mid);
Array.Copy(t_pointer,0,m_children,0,mid+1);
newMedian = temp[mid];
Array.Copy(temp,mid+1,newRight.m_keys,0,m_order-mid-1);
Array.Copy(t_pointer,mid+1,newRight.m_children,0,m_order-mid);
m_keyNums = (short)mid;
newRight.m_keyNums = (short)(m_order - mid -1);
this.m_dirty = true;
newRight.m_dirty = true;
}
/// <summary>
/// split the leaf into two, leave left half in current leaf, and move right half into right node
/// </summary>
/// <param name="newKey"></param>
/// <param name="median">the middle key is popped up</param>
/// <param name="right"></param>
public void SplitAtLeaf(IKey newKey, int pos, ref IKey median, ref BNode right)
{
Debug.Assert(this.m_leaf);
Debug.Assert(this.IsFull);
right.SetOrder(this.m_order);
right.m_leaf = this.m_leaf;
int mid = m_order >> 1;
//copy current keys into a bigger array
IKey[] temp = new IKey[m_order];
Array.Copy(m_keys,0,temp,0,m_order - 1);
//insert the newKey into the pos location
//shift later keys to the right
for (int i=this.m_keyNums; i>pos; i--)
{
temp[i] = temp[i-1];
}
temp[pos] = newKey;
median = temp[mid];
//copy left half to current leaf
for (int i=0; i<mid; i++)
{
m_keys[i] = temp[i];
}
//copy right half to right leaf
for (int i=mid+1; i<temp.Length; i++)
{
right.m_keys[i-mid-1] = temp[i];
}
m_keyNums = (short)mid;
right.m_keyNums = (short)(m_order - 1 - mid);
this.m_dirty = true;
right.m_dirty = true;
}
/// <summary>
/// Create the internal storage for the dbFile.
/// Note:
/// 1. a helper file for segment managment b-tree is also created if this database file
/// does not exist.
/// </summary>
/// <param name="dbFile"></param>
public ObjectStore(string dbFileName)
{
m_dbFile = new DiskFile(dbFileName);
m_indexFile = new DiskFile(dbFileName + ".idx");
m_indexPageManager = new memSegmentManager(m_indexFile);
if (m_indexPageManager.Header.InitializeNeeded)
{
m_indexPageManager.Header.NextSegmentId = 0;
m_indexPageManager.Header.NextObjectId = 0;
m_indexPageManager.Header.NextClassId = 0;
//initialize the segment b-tree's top node id
OOD.Imp.Storage.BNode segTreeTop = new OOD.Imp.Storage.BNode();
m_indexPageManager.GetNewSegment(segTreeTop);
segTreeTop.SetOrder(m_segTreeNodeOrder);
segTreeTop.Leaf = true;
m_indexPageManager.Header.SegmentTreeTopNodeSId = segTreeTop.SegmentID;
//initialize the space b-tree's top node id
BNode spaceTreeTop = new BNode();
m_indexPageManager.GetNewSegment(spaceTreeTop);
spaceTreeTop.SetOrder(m_spaceTreeNodeOrder);
spaceTreeTop.Leaf = true;
m_indexPageManager.Header.FreeSpaceTreeTopNodeSId = spaceTreeTop.SegmentID;
}
m_segmentIndexTree = new SegTree(m_indexPageManager.Header.SegmentTreeTopNodeSId, m_indexPageManager);
m_spaceIndexTree = new SpaceTree(m_indexPageManager.Header.FreeSpaceTreeTopNodeSId, m_indexPageManager, m_dbFile);
m_dbSegmentManager = new dbSegmentManager(
m_indexPageManager.Header.NextSegmentId,
m_segmentIndexTree,
m_spaceIndexTree,
m_dbFile);
if (m_indexPageManager.Header.InitializeNeeded)
{
BNode catalogTop = new BNode();
m_dbSegmentManager.GetNewSegment(catalogTop);
catalogTop.SetOrder(m_catalogTreeNodeOrder);
catalogTop.Leaf = true;
m_indexPageManager.Header.CatalogTreeTopNodeSId = catalogTop.SegmentID;
}
m_catalogTree = new CatalogTree(
m_indexPageManager.Header.CatalogTreeTopNodeSId,
m_dbSegmentManager,
m_indexPageManager.Header.NextClassId);
m_classCache = new LRUHashtable(m_cache_size, m_classCacheLimit);
m_objectTreeCache = new LRUHashtable(m_cache_size, m_objectTreeCacheLimit);
//bring top node's segment tree, space tree, catalog tree into cache, they will be needed anyway
if (!m_indexPageManager.Header.InitializeNeeded)
{
m_indexPageManager.GetSegment(m_segmentIndexTree.TopNodSegId, new BNode(), new KSegId());
m_indexPageManager.GetSegment(m_spaceIndexTree.TopNodeSId, new BNode(), new KOffset());
m_dbSegmentManager.GetSegment(m_catalogTree.TopNodeSId, new BNode(), new KCatalog());
}
}
/// <summary>
/// Remove the key from the tree.
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public bool Delete(IKey key)
{
int pos = -1;
System.Collections.Stack visited = new System.Collections.Stack();
System.Collections.Stack viaLinks = new System.Collections.Stack();
//find the node which contains the key
BNode n = FindNode(m_top, key, ref pos, visited, viaLinks);
if (n == null)
{
return(false);
}
else
{
if (n.Leaf)
{
n.RemoveAtLeaf(key, pos);
}
else
{
visited.Push(n);
uint nextNodeId = n.GetChildAt(pos + 1);
viaLinks.Push(pos + 1);
BNode t_node = (BNode)m_sgManager.GetSegment(nextNodeId, m_nodeFactory, m_keyFactory);
//find the leaf most leaf in its right sub-tree
while (!t_node.Leaf)
{
visited.Push(t_node);
nextNodeId = t_node.GetChildAt(0);
viaLinks.Push(0);
t_node = (BNode)m_sgManager.GetSegment(nextNodeId, m_nodeFactory, m_keyFactory);
}
Debug.Assert(t_node.Leaf);
IKey successor = t_node.GetKeyAt(0);
//replace the key&data in n with the successor
n.ReplaceKeyDataWSuccessor(key, successor, pos);
//remove successor from the leaf node
t_node.RemoveAtLeaf(successor, 0);
n = t_node;
}
}
//now n is the leaf node where the real deletion happens
//visited keep all the parents visited so far, viaLinks keeps which links we followed
while (n.IsUnderflow && n.SegmentID != m_top_sid)
{
BNode parent = (BNode)visited.Pop();
//get left/right brother
int followed = (int)viaLinks.Pop();
BNode left = (followed > 0? (BNode)m_sgManager.GetSegment(parent.GetChildAt(followed - 1), m_nodeFactory, m_keyFactory) : null);
BNode right = (followed < parent.KeyNums ? (BNode)m_sgManager.GetSegment(parent.GetChildAt(followed + 1), m_nodeFactory, m_keyFactory) : null);
Debug.Assert(left != null || right != null);
bool combined = false;
//try combin with right first
if (right != null && right.KeyNums == right.ReqMinimum)
{
//combine with the right
parent.CombineChildren(followed, n, right);
Debug.Assert(right.KeyNums == 0);
Debug.Assert(n.KeyNums > n.ReqMinimum);
m_sgManager.FreeSegment(right);
combined = true;
if (parent.KeyNums == 0)
{
Debug.Assert(parent.Leaf == false);
Debug.Assert(parent.SegmentID == this.m_top_sid);
//tree will shrink
this.m_top_sid = n.SegmentID;
m_sgManager.FreeSegment(parent);
break;
}
}
else if (left != null && left.KeyNums == left.ReqMinimum)
{
//combine with the left
parent.CombineChildren(followed - 1, left, n);
Debug.Assert(n.KeyNums == 0);
Debug.Assert(left.KeyNums > left.ReqMinimum);
m_sgManager.FreeSegment(n);
combined = true;
if (parent.KeyNums == 0)
{
Debug.Assert(parent.Leaf == false);
Debug.Assert(parent.SegmentID == this.m_top_sid);
//tree will shrink
this.m_top_sid = left.SegmentID;
m_sgManager.FreeSegment(parent);
break;
}
}
if (!combined)
{
//try redistrubute if combine is not possible
if (right != null && right.KeyNums > right.ReqMinimum)
{
//redistribute one entry from right node
parent.RedistributeRight2Left(followed, n, right);
}
else if (left != null && left.KeyNums > left.ReqMinimum)
{
//redistribute with left
parent.RedistributeLeft2Right(followed - 1, left, n);
}
}
else
{
n = parent;
}
}
return(true);
}
/// <summary>
/// Insert the newKey into this B-tree,
/// </summary>
/// <param name="newKey"></param>
/// <returns></returns>
public bool Insert(IKey newKey)
{
//find the leaf where the newKey should be in
BNode n = m_top;
System.Collections.Stack visited = new System.Collections.Stack();
int pos = -1;
while (!n.Leaf)
{
IKey temp = n.SearchKey(newKey, ref pos);
if (temp == null)
{
uint nextNodeId = n.GetChildAt(pos);
visited.Push(n);
n = (BNode)m_sgManager.GetSegment(nextNodeId, m_nodeFactory, m_keyFactory);
}
else
{
return(false);
}
}
//now BNode n is the leaf where insert should happen
IKey t_temp = n.SearchKey(newKey, ref pos);
if (t_temp == null)
{
//not exists, go ahead to insert the new key
if (!n.IsFull)
{
n.InsertAtLeaf(newKey, pos);
return(true);
}
else
{
//split needed for this node
BNode right = new BNode();
m_sgManager.GetNewSegment(right);
IKey median = null;
n.SplitAtLeaf(newKey, pos, ref median, ref right); //this split is at leaf
bool finished = false;
//now n holds the left half of the items,
//right holds the right half items, median is the middle key
while (!finished)
{
//parent is node middle key will be inserted
BNode parent = (visited.Count > 0 ? (BNode)visited.Pop() : null);
if (parent == null)
{
//new top node is needed
BNode new_top = new BNode();
m_sgManager.GetNewSegment(new_top);
new_top.SetOrder(m_top.Order);
new_top.Leaf = false;
new_top.InsertFirstKey(median, n.SegmentID, right.SegmentID);
this.m_top_sid = new_top.SegmentID;
return(true);
}
else
{
IKey tt = parent.SearchKey(median, ref pos);
if (tt != null)
{
return(false);
}
if (!parent.IsFull)
{
parent.InsertAtInternal(median, pos, right.SegmentID);
return(true);
}
else
{
//parent is full again
BNode newRight = new BNode();
m_sgManager.GetNewSegment(newRight);
newRight.SetOrder(parent.Order);
newRight.Leaf = parent.Leaf;
//this split will insert median into the parent, then split and new middle key is newMedian
IKey newMedian;
parent.SplitAtInternal(median, pos, right.SegmentID, out newMedian, newRight);
n = parent;
median = newMedian;
right = newRight;
}
}
}
}
}
else
{
return(false);
}
return(false);
}