public TreeBranch(NodeId nodeId, long[] data, int dataSize)
{
if (nodeId.IsInMemory)
throw new ArgumentException("Only store nodes permitted.");
this.nodeId = nodeId;
children = data;
childrenCount = (dataSize + 2)/5;
}
public TreeSystemTransaction(ITreeSystem treeStore, long versionId, NodeId rootNodeId, bool readOnly)
{
this.treeStore = treeStore;
this.rootNodeId = rootNodeId;
this.versionId = versionId;
updateVersion = 0;
nodeDeletes = null;
nodeInserts = null;
this.readOnly = readOnly;
disposed = false;
}
public TreeBranch(NodeId nodeId, int maxChildrenCount)
{
if (!nodeId.IsInMemory)
throw new ArgumentException("Only heap node permitted.");
if ((maxChildrenCount%2) != 0)
throw new ArgumentException("max_children_count must be a multiple of 2.");
if (maxChildrenCount > 65530)
throw new ArgumentException("Branch children count is limited to 65530");
if (maxChildrenCount < 6)
// While I did test with 4, tree balancing is rather tough at 4 so we
// should have this at at least 6.
throw new ArgumentException("max_children_count must be >= 6");
this.nodeId = nodeId;
children = new long[(maxChildrenCount*5) - 2];
childrenCount = 0;
}
internal void FlushNodesToStore(NodeId[] nodeIds)
{
// If not disposed,
if (!disposed) {
// Compact the entire tree
object[] mergeBuffer = new object[5];
CompactNode(Key.Head, RootNodeId, mergeBuffer, Key.Head, Key.Tail);
// Flush the reference node list,
RootNodeId = (FlushNodes(RootNodeId, nodeIds));
// Update the version so any data file objects will flush with the
// changes.
++updateVersion;
// Check out the changes
treeStore.CheckPoint();
}
}
internal bool IsHeapNode(NodeId nodeId)
{
return nodeId.IsInMemory;
}
private int PopulateSequence(NodeId id, TreeWrite sequence)
{
// If it's not a heap node, return
if (!IsHeapNode(id))
return -1;
// It is a heap node, so fetch
ITreeNode node = FetchNode(id);
// Is it a leaf or a branch?
if (node is TreeLeaf)
// If it's a leaf, simply write it out
return sequence.NodeWrite(node);
if (node is TreeBranch) {
// This is a branch,
// Sequence this branch to be written out,
int branchId = sequence.NodeWrite(node);
// For each child in the branch,
TreeBranch branch = (TreeBranch) node;
int sz = branch.ChildCount;
for (int i = 0; i < sz; ++i) {
NodeId child = branch.GetChild(i);
// Sequence the child
int childId = PopulateSequence(child, sequence);
// If something could be sequenced in the child,
if (childId != -1) {
// Make the branch command,
sequence.BranchLink(branchId, i, childId);
}
}
// Return the id of the branch in the sequence,
return branchId;
} else {
throw new ApplicationException("Unknown node type.");
}
}
public AreaTreeLeaf(NodeId nodeId, int leafSize, IArea area)
{
this.nodeId = nodeId;
this.leafSize = leafSize;
this.area = area;
}
internal void SetChild(NodeId childPointer, int n)
{
CheckReadOnly();
SetChildOverride(childPointer, n);
}
private void LogStoreChange(byte type, NodeId pointer)
{
if (!treeStore.NotifyNodeChanged)
return;
// Special node type changes are not logged
if (pointer.IsSpecial)
return;
if (type == 0) {
// This type is for deleted nodes,
NodeDeletes.Add(pointer);
} else if (type == 1) {
// This type is for inserts,
NodeInserts.Add(pointer);
} else {
throw new ApplicationException("Incorrect type");
}
}
public TreeReportNode CreateDiagnosticGraph()
{
CheckErrorState();
// Create the header node
TreeReportNode headerNode = new TreeReportNode("header", headerId);
// Get the header area
IArea headerArea = nodeStore.GetArea(headerId);
headerArea.Position = 8;
// Read the versions list,
long versionListRef = headerArea.ReadInt8();
// Create the version node
TreeReportNode versionsNode =
new TreeReportNode("versions list", versionListRef);
// Set this as a child to the header
headerNode.ChildNodes.Add(versionsNode);
// Read the versions list area
// magic(int), versions count(int), list of version id objects.
IArea versionsArea = nodeStore.GetArea(versionListRef);
if (versionsArea.ReadInt4() != 0x01433)
{
throw new IOException("Incorrect magic value 0x01433");
}
int versCount = versionsArea.ReadInt4();
// For each id from the versions area, read in the associated VersionInfo
// object into the 'vers' array.
for (int i = 0; i < versCount; ++i)
{
long vInfoRef = versionsArea.ReadInt8();
// Set up the information in our node
TreeReportNode vInfoNode = new TreeReportNode("version", vInfoRef);
// Read in the version information node
IArea vInfoArea = nodeStore.GetArea(vInfoRef);
int magic = vInfoArea.ReadInt4();
int ver = vInfoArea.ReadInt4();
long versionId = vInfoArea.ReadInt8();
long rnrHigh = vInfoArea.ReadInt8();
long rnrLow = vInfoArea.ReadInt8();
NodeId rootNodeId = new NodeId(rnrHigh, rnrLow);
vInfoNode.SetProperty("MAGIC", magic);
vInfoNode.SetProperty("VER", ver);
vInfoNode.SetProperty("version_id", versionId);
// Make the deleted area list into a property
int deletedAreaCount = vInfoArea.ReadInt4();
if (deletedAreaCount > 0)
{
for (int n = 0; n < deletedAreaCount; ++n)
{
long delnHigh = vInfoArea.ReadInt8();
long delnLow = vInfoArea.ReadInt8();
NodeId delNodeId = new NodeId(delnHigh, delnLow);
vInfoNode.ChildNodes.Add(new TreeReportNode("delete", delNodeId));
}
}
// Add the child node (the root node of the version graph).
vInfoNode.ChildNodes.Add(CreateDiagnosticRootGraph(Key.Head, rootNodeId));
// Add this to the version list node
versionsNode.ChildNodes.Add(vInfoNode);
}
// Return the header node
return(headerNode);
}
private Object[] DeleteFromLeaf(long leftOffset, NodeId leaf, long startPos, long endPos, Key inLeftKey)
{
Debug.Assert(startPos < endPos);
TreeLeaf treeLeaf = (TreeLeaf) UnfreezeNode(FetchNode(leaf));
const int leafStart = 0;
int leafEnd = treeLeaf.Length;
int delStart = (int) Math.Max(startPos - leftOffset, (long) leafStart);
int delEnd = (int) Math.Min(endPos - leftOffset, (long) leafEnd);
int removeAmount = delEnd - delStart;
// Remove from the end point,
treeLeaf.Shift(delEnd, -removeAmount);
return new object[] {
treeLeaf.Id,
(long) removeAmount,
inLeftKey, false
};
}
private ITreeNode FetchNode(NodeId nodeId)
{
// Is it a special static node?
if (nodeId.IsSpecial)
{
return(SpecialStaticNode(nodeId));
}
// Is this a branch node in the cache?
NodeId cacheKey = nodeId;
TreeBranch branch;
lock (branchCache) {
branch = (TreeBranch)branchCache.Get(cacheKey);
if (branch != null)
{
return(branch);
}
}
// Not found in the cache, so fetch the area from the backing store and
// create the node type.
// Get the area for the node
IArea nodeArea = nodeStore.GetArea(ToInt64StoreAddress(nodeId));
// Wrap around a buffered BinaryRader for reading values from the store.
BinaryReader input = new BinaryReader(new AreaInputStream(nodeArea, 256));
short nodeType = input.ReadInt16();
// Is the node type a leaf node?
if (nodeType == StoreLeafType)
{
// Read the key
input.ReadInt16(); // version
input.ReadInt32(); // reference count
int leafSize = input.ReadInt32();
// Return a leaf that's mapped to the data in the store
nodeArea.Position = 0;
return(new AreaTreeLeaf(nodeId, leafSize, nodeArea));
}
// Is the node type a branch node?
if (nodeType == StoreBranchType)
{
// Note that the entire branch is loaded into memory now,
input.ReadInt16(); // version
int childDataSize = input.ReadInt32();
long[] dataArr = new long[childDataSize];
for (int i = 0; i < childDataSize; ++i)
{
dataArr[i] = input.ReadInt64();
}
branch = new TreeBranch(nodeId, dataArr, childDataSize);
// Put this branch in the cache,
lock (branchCache) {
branchCache.Set(cacheKey, branch);
// And return the branch
return(branch);
}
}
throw new ApplicationException("Unknown node type: " + nodeType);
}
public long Create()
{
if (initialized)
{
throw new InvalidOperationException("This tree store is already initialized.");
}
// Temporary node heap for creating a starting database
TreeNodeHeap nodeHeap = new TreeNodeHeap(17, 4 * 1024 * 1024);
// Write a root node to the store,
// Create an empty head node
TreeLeaf headLeaf = nodeHeap.CreateLeaf(null, Key.Head, 256);
// Insert a tree identification pattern
headLeaf.Write(0, new byte[] { 1, 1, 1, 1 }, 0, 4);
// Create an empty tail node
TreeLeaf tailLeaf = nodeHeap.CreateLeaf(null, Key.Tail, 256);
// Insert a tree identification pattern
tailLeaf.Write(0, new byte[] { 1, 1, 1, 1 }, 0, 4);
// The write sequence,
TreeWrite seq = new TreeWrite();
seq.NodeWrite(headLeaf);
seq.NodeWrite(tailLeaf);
IList <NodeId> refs = Persist(seq);
// Create a branch,
TreeBranch rootBranch = nodeHeap.CreateBranch(null, MaxBranchSize);
rootBranch.Set(refs[0], 4, Key.Tail, refs[1], 4);
seq = new TreeWrite();
seq.NodeWrite(rootBranch);
refs = Persist(seq);
// The written root node reference,
NodeId rootId = refs[0];
// Delete the head and tail leaf, and the root branch
nodeHeap.Delete(headLeaf.Id);
nodeHeap.Delete(tailLeaf.Id);
nodeHeap.Delete(rootBranch.Id);
// Write this version info to the store,
long versionId = WriteSingleVersionInfo(1, rootId, new List <NodeId>(0));
// Make a first version
VersionInfo versionInfo = new VersionInfo(1, rootId, versionId);
versions.Add(versionInfo);
// Flush this to the version list
IAreaWriter versionList = nodeStore.CreateArea(64);
versionList.WriteInt4(0x01433);
versionList.WriteInt4(1);
versionList.WriteInt8(versionId);
versionList.Finish();
// Get the versions id
long versionListId = versionList.Id;
// The final header
IAreaWriter header = nodeStore.CreateArea(64);
header.WriteInt4(0x09391); // The magic value,
header.WriteInt4(1); // The version
header.WriteInt8(versionListId);
header.Finish();
// Set up the internal variables,
headerId = header.Id;
initialized = true;
// And return the header reference
return(headerId);
}
internal static ITreeNode SpecialStaticNode(NodeId nodeId)
{
return(nodeId.CreateSpecialTreeNode());
}
private void DisposeOldVersions()
{
List <object> disposeList = new List <object>();
lock (versions) {
// size - 1 because we don't want to delete the very last version,
int sz = versions.Count - 1;
bool foundLockedEntry = false;
for (int i = 0; i < sz && foundLockedEntry == false; ++i)
{
VersionInfo vinfo = versions[i];
// If this version isn't locked,
if (vinfo.NotLocked)
{
// Add to the dispose list
disposeList.Add(vinfo);
// And delete from the versions list,
versions.RemoveAt(i);
--sz;
--i;
}
else
{
// If it is locked, we exit the loop
foundLockedEntry = true;
}
}
}
// If there are entries to dispose?
if (disposeList.Count > 0)
{
// We synchronize here to ensure the versions list can't be modified by
// a commit operation while we are disposing this.
lock (this) {
// Run within a write lock on the store
try {
nodeStore.LockForWrite();
// First we write out a modified version header minus the versions we
// are to delete,
// Get the current version list
IMutableArea headerArea = nodeStore.GetMutableArea(headerId);
headerArea.Position = 8;
long versionListId = headerArea.ReadInt8();
// Read information from the old version info,
IArea versionListArea = nodeStore.GetArea(versionListId);
versionListArea.ReadInt4(); // The magic
int versionCount = versionListArea.ReadInt4();
int newVersionCount = versionCount - disposeList.Count;
// Create a new list,
IAreaWriter newVersionList = nodeStore.CreateArea(8 + (8 * newVersionCount));
newVersionList.WriteInt4(0x01433);
newVersionList.WriteInt4(newVersionCount);
// Skip the versions we are deleting,
for (int i = 0; i < disposeList.Count; ++i)
{
versionListArea.ReadInt8();
}
// Now copy the list from the new point
for (int i = 0; i < newVersionCount; ++i)
{
newVersionList.WriteInt8(versionListArea.ReadInt8());
}
newVersionList.Finish();
// Write the new area to the header,
headerArea.Position = 8;
headerArea.WriteInt8(newVersionList.Id);
// Delete the old version list Area,
nodeStore.DeleteArea(versionListId);
// Dispose the version info,
int sz = disposeList.Count;
for (int i = 0; i < sz; ++i)
{
VersionInfo vinfo = (VersionInfo)disposeList[i];
long vRef = vinfo.VersionInfoRef;
IArea versionArea = nodeStore.GetArea(vRef);
int magic = versionArea.ReadInt4();
int rev = versionArea.ReadInt4();
// Check the magic,
if (magic != 0x04EA23)
{
throw new ApplicationException("Magic value for version area is incorrect.");
}
long verId = versionArea.ReadInt8();
long nrnHigh = versionArea.ReadInt8();
long nrnLow = versionArea.ReadInt8();
int nodeCount = versionArea.ReadInt4();
// For each node,
for (int n = 0; n < nodeCount; ++n)
{
// Read the next area
long drnHigh = versionArea.ReadInt8();
long drnLow = versionArea.ReadInt8();
NodeId delNodeId = new NodeId(drnHigh, drnLow);
// Cleanly disposes the node
DoDisposeNode(delNodeId);
}
// Delete the node header,
nodeStore.DeleteArea(vRef);
}
} finally {
nodeStore.UnlockForWrite();
}
}
}
}
private long WriteVersionsList(long versionId, TreeSystemTransaction tran)
{
lock (this) {
// Write the version info and the deleted refs to a new area,
NodeId rootNodeId = tran.RootNodeId;
if (rootNodeId.IsInMemory)
{
throw new ApplicationException("Assertion failed, root_node is on heap.");
}
// Get the list of all nodes deleted in the transaction
List <NodeId> deletedRefs = tran.NodeDeletes;
// Sort it
deletedRefs.Sort();
// Check for any duplicate entries (we shouldn't double delete stuff).
for (int i = 1; i < deletedRefs.Count; ++i)
{
if (deletedRefs[i - 1].Equals(deletedRefs[i]))
{
// Oops, duplicated delete
throw new ApplicationException("PRAGMATIC_CHECK failed: duplicate records in delete list.");
}
}
long theVersionId = WriteSingleVersionInfo(versionId, rootNodeId, deletedRefs);
// Now update the version list by copying the list and adding the new ref
// to the end.
// Get the current version list
IMutableArea headerArea = nodeStore.GetMutableArea(headerId);
headerArea.Position = 8;
long versionListId = headerArea.ReadInt8();
// Read information from the old version info,
IArea versionListArea = nodeStore.GetArea(versionListId);
versionListArea.ReadInt4(); // The magic
int versionCount = versionListArea.ReadInt4();
// Create a new list,
IAreaWriter newVersionList = nodeStore.CreateArea(8 + (8 * (versionCount + 1)));
newVersionList.WriteInt4(0x01433);
newVersionList.WriteInt4(versionCount + 1);
for (int i = 0; i < versionCount; ++i)
{
newVersionList.WriteInt8(versionListArea.ReadInt8());
}
newVersionList.WriteInt8(theVersionId);
newVersionList.Finish();
// Write the new area to the header,
headerArea.Position = 8;
headerArea.WriteInt8(newVersionList.Id);
// Delete the old version list Area,
nodeStore.DeleteArea(versionListId);
// Done,
return(theVersionId);
}
}
public TreeBranch(NodeId nodeId, TreeBranch branch, int maxChildrenCount)
: this(nodeId, maxChildrenCount)
{
Array.Copy(branch.children, 0, children, 0, Math.Min(branch.children.Length, children.Length));
childrenCount = branch.ChildCount;
}
private TreeReportNode CreateDiagnosticRootGraph(Key leftKey, NodeId id)
{
// The node being returned
TreeReportNode node;
// Open the area
IArea area = nodeStore.GetArea(ToInt64StoreAddress(id));
// What type of node is this?
short nodeType = area.ReadInt2();
// The version
short ver = area.ReadInt2();
if (nodeType == StoreLeafType)
{
// Read the reference count,
long refCount = area.ReadInt4();
// The number of bytes in the leaf
int leafSize = area.ReadInt4();
// Set up the leaf node object
node = new TreeReportNode("leaf", id);
node.SetProperty("VER", ver);
node.SetProperty("key", leftKey.ToString());
node.SetProperty("reference_count", refCount);
node.SetProperty("leaf_size", leafSize);
}
else if (nodeType == StoreBranchType)
{
// The data size area containing the children information
int childDataSize = area.ReadInt4();
long[] dataArr = new long[childDataSize];
for (int i = 0; i < childDataSize; ++i)
{
dataArr[i] = area.ReadInt8();
}
// Create the TreeBranch object to query it
TreeBranch branch = new TreeBranch(id, dataArr, childDataSize);
// Set up the branch node object
node = new TreeReportNode("branch", id);
node.SetProperty("VER", ver);
node.SetProperty("key", leftKey.ToString());
node.SetProperty("branch_size", branch.ChildCount);
// Recursively add each child into the tree
for (int i = 0; i < branch.ChildCount; ++i)
{
NodeId childId = branch.GetChild(i);
// If the id is a special node, skip it
if (childId.IsSpecial)
{
// Should we record special nodes?
}
else
{
Key newLeftKey = (i > 0) ? branch.GetKey(i) : leftKey;
TreeReportNode bn = new TreeReportNode("child_meta", id);
bn.SetProperty("extent", branch.GetChildLeafElementCount(i));
node.ChildNodes.Add(bn);
node.ChildNodes.Add(CreateDiagnosticRootGraph(newLeftKey, childId));
}
}
}
else
{
throw new IOException("Unknown node type: " + nodeType);
}
return(node);
}
private void CompactNode(Key farLeft, NodeId id, object[] mergeBuffer, Key minBound, Key maxBound)
{
// If the ref is not on the heap, return the ref,
if (!IsHeapNode(id))
return;
// Fetch the node,
ITreeNode node = FetchNode(id);
// If the node is a leaf, return the ref,
if (node is TreeLeaf)
return;
// If the node is a branch,
if (node is TreeBranch) {
// Cast to a branch
TreeBranch branch = (TreeBranch) node;
// We ask the node for the child sub-tree that will contain the range
// of this key
int firstChildI = branch.SearchFirst(minBound);
int lastChildI = branch.SearchLast(maxBound);
// first_child_i may be negative which means a key reference is equal
// to the key being searched, in which case we follow the left branch.
if (firstChildI < 0) {
firstChildI = -(firstChildI + 1);
}
// Compact the children,
for (int x = firstChildI; x <= lastChildI; ++x) {
// Change far left to represent the new far left node
Key newFarLeft = (x > 0) ? branch.GetKey(x) : farLeft;
// We don't change max_bound because it's not necessary.
CompactNode(newFarLeft, branch.GetChild(x), mergeBuffer, minBound, maxBound);
}
// The number of children in this branch,
int sz = branch.ChildCount;
// Now try and merge the compacted children,
int i = firstChildI;
// We must not let there be less than 3 children
while (sz > 3 && i <= lastChildI - 1) {
// The left and right children nodes,
NodeId leftChildId = branch.GetChild(i);
NodeId rightChildId = branch.GetChild(i + 1);
// If at least one of them is a heap node we attempt to merge the
// nodes,
if (IsHeapNode(leftChildId) || IsHeapNode(rightChildId)) {
// Set the left left key and right left key of the references,
Key leftLeftKey = (i > 0) ? branch.GetKey(i) : farLeft;
Key rightLeftKey = branch.GetKey(i + 1);
// Attempt to merge the nodes,
int nodeResult = MergeNodes(branch.GetKey(i + 1),
leftChildId, rightChildId,
leftLeftKey, rightLeftKey,
mergeBuffer);
// If we merged into a single node then we update the left and
// delete the right
if (nodeResult == 1) {
branch.SetChild((NodeId) mergeBuffer[0], i);
branch.SetChildLeafElementCount((long) mergeBuffer[1], i);
branch.RemoveChild(i + 1);
// Reduce the size but don't increase i, because we may want to
// merge again.
--sz;
--lastChildI;
} else if (nodeResult == 2) {
// Two result but there was a change (the left was increased in
// size)
branch.SetChild((NodeId) mergeBuffer[0], i);
branch.SetChildLeafElementCount((long) mergeBuffer[1], i);
branch.SetKeyToLeft((Key) mergeBuffer[2], i + 1);
branch.SetChild((NodeId) mergeBuffer[3], i + 1);
branch.SetChildLeafElementCount((long) mergeBuffer[4], i + 1);
++i;
} else {
// Otherwise, no change so skip to the next child,
++i;
}
}
// left or right are not nodes on the heap so go to next,
else {
++i;
}
}
}
}
private long ToInt64StoreAddress(NodeId nodeId)
{
return(nodeId.Low);
}
private ITreeNode FetchNodeIfLocallyAvailable(NodeId nodeId)
{
// If it's a heap node,
if (IsHeapNode(nodeId)) {
return FetchNode(nodeId);
}
// If the node is locally available, return it,
if (treeStore.IsNodeAvailable(nodeId)) {
return treeStore.FetchNodes(new NodeId[] {nodeId})[0];
}
// Otherwise return null
return null;
}
public IList <NodeId> Persist(TreeWrite write)
{
try {
nodeStore.LockForWrite();
IList <ITreeNode> allBranches = write.BranchNodes;
IList <ITreeNode> allLeafs = write.LeafNodes;
List <ITreeNode> nodes = new List <ITreeNode>(allBranches.Count + allLeafs.Count);
nodes.AddRange(allBranches);
nodes.AddRange(allLeafs);
// The list of nodes to be allocated,
int sz = nodes.Count;
// The list of allocated referenced for the nodes,
NodeId[] refs = new NodeId[sz];
// The list of area writers,
IAreaWriter[] writers = new IAreaWriter[sz];
// Allocate the space first,
for (int i = 0; i < sz; ++i)
{
ITreeNode node = nodes[i];
// Is it a branch node?
if (node is TreeBranch)
{
TreeBranch branch = (TreeBranch)node;
int ndsz = branch.NodeDataSize;
writers[i] = nodeStore.CreateArea(4 + 4 + (ndsz * 8));
}
// Otherwise, it must be a leaf node,
else
{
TreeLeaf leaf = (TreeLeaf)node;
int lfsz = leaf.Length;
writers[i] = nodeStore.CreateArea(12 + lfsz);
}
// Set the reference,
refs[i] = FromInt64StoreAddress(writers[i].Id);
}
// Now write out the data,
for (int i = 0; i < sz; ++i)
{
ITreeNode node = nodes[i];
// Is it a branch node?
if (node is TreeBranch)
{
TreeBranch branch = (TreeBranch)node;
// The number of children
int chsz = branch.ChildCount;
// For each child, if it's a heap node, look up the child id and
// reference map in the sequence and set the reference accordingly,
for (int o = 0; o < chsz; ++o)
{
NodeId childId = branch.GetChild(o);
if (childId.IsInMemory)
{
// The ref is currently on the heap, so adjust accordingly
int refId = write.LookupRef(i, o);
branch.SetChild(refs[refId], o);
}
}
// Write out the branch to the store
long[] nodeData = branch.NodeData;
int ndsz = branch.NodeDataSize;
IAreaWriter writer = writers[i];
writer.WriteInt2(StoreBranchType);
writer.WriteInt2(1); // version
writer.WriteInt4(ndsz);
for (int o = 0; o < ndsz; ++o)
{
writer.WriteInt8(nodeData[o]);
}
writer.Finish();
// Make this into a branch node and add to the cache,
branch = new TreeBranch(refs[i], nodeData, ndsz);
// Put this branch in the cache,
lock (branchCache) {
branchCache.Set(refs[i], branch);
}
}
// Otherwise, it must be a leaf node,
else
{
TreeLeaf leaf = (TreeLeaf)node;
IAreaWriter writer = writers[i];
writer.WriteInt2(StoreLeafType);
writer.WriteInt2(1); // version
writer.WriteInt4(1); // reference count
writer.WriteInt4(leaf.Length);
leaf.WriteTo(writer);
writer.Finish();
}
}
return(refs);
} finally {
nodeStore.UnlockForWrite();
}
}
public SparseLeafNode(NodeId nodeId, byte sparseByte, int leafSize)
{
this.nodeId = nodeId;
this.leafSize = leafSize;
this.sparseByte = sparseByte;
}
private Object[] RecurseRemoveBranches(long leftOffset, int height, NodeId node, long startPos, long endPos, Key inLeftKey)
{
// Do we know if this is a leaf node?
if (treeHeight == height)
return DeleteFromLeaf(leftOffset, node, startPos, endPos, inLeftKey);
// Fetch the node,
ITreeNode treeNode = FetchNode(node);
if (treeNode is TreeLeaf) {
// Leaf reach, so set the tree height and return
treeHeight = height;
return DeleteFromLeaf(leftOffset, node, startPos, endPos, inLeftKey);
}
// The amount removed,
long removeCount = 0;
// This is a branch,
TreeBranch treeBranch = (TreeBranch) treeNode;
treeBranch = (TreeBranch) UnfreezeNode(treeBranch);
Key parentLeftKey = inLeftKey;
// Find all the children branches between the bounds,
int childCount = treeBranch.ChildCount;
long pos = leftOffset;
for (int i = 0; i < childCount && pos < endPos; ++i) {
long childNodeSize = treeBranch.GetChildLeafElementCount(i);
long nextPos = pos + childNodeSize;
// Test if start_pos/end_pos bounds intersects with this child,
if (startPos < nextPos && endPos > pos) {
// Yes, we intersect,
// Make sure the branch is on the heap,
NodeId childNode = treeBranch.GetChild(i);
// If we intersect entirely remove the child from the branch,
if (pos >= startPos && nextPos <= endPos) {
// Delete the child tree,
DeleteChildTree(height + 1, childNode);
removeCount += childNodeSize;
// If removing the first child, bubble up a new left_key
if (i == 0) {
parentLeftKey = treeBranch.GetKey(1);
}
// Otherwise parent left key doesn't change
else {
parentLeftKey = inLeftKey;
}
// Remove the child from the branch,
treeBranch.RemoveChild(i);
--i;
--childCount;
} else {
// We don't intersect entirely, so recurse on this,
// The left key
Key rLeftKey = (i == 0) ? inLeftKey : treeBranch.GetKey(i);
object[] rv = RecurseRemoveBranches(pos, height + 1, childNode, startPos, endPos, rLeftKey);
NodeId newChildRef = (NodeId) rv[0];
long removedInChild = (long) rv[1];
Key childLeftKey = (Key) rv[2];
removeCount += removedInChild;
// Update the child,
treeBranch.SetChild(newChildRef, i);
treeBranch.SetChildLeafElementCount(childNodeSize - removedInChild, i);
if (i == 0) {
parentLeftKey = childLeftKey;
} else {
treeBranch.SetKeyToLeft(childLeftKey, i);
parentLeftKey = inLeftKey;
}
}
}
// Next child in the branch,
pos = nextPos;
}
// Return the reference and remove count,
bool parentRebalance = (treeBranch.ChildCount <= 2);
return new Object[] {
treeBranch.Id, removeCount,
parentLeftKey, parentRebalance
};
}
private int MergeNodes(Key middleKeyValue, NodeId leftId, NodeId rightId, Key leftLeftKey, Key rightLeftKey, object[] mergeBuffer)
{
// Fetch the nodes,
ITreeNode leftNode = FetchNode(leftId);
ITreeNode rightNode = FetchNode(rightId);
// Are we merging branches or leafs?
if (leftNode is TreeLeaf) {
TreeLeaf lleaf = (TreeLeaf) leftNode;
TreeLeaf rleaf = (TreeLeaf) rightNode;
// Check the keys are identical,
if (leftLeftKey.Equals(rightLeftKey)) {
// 80% capacity on a leaf
int capacity80 = (int) (0.80*MaxLeafByteSize);
// True if it's possible to full merge left and right into a single
bool fullyMerge = lleaf.Length + rleaf.Length <= MaxLeafByteSize;
// Only proceed if the leafs can be fully merged or the left is less
// than 80% full,
if (fullyMerge || lleaf.Length < capacity80) {
// Move elements from the right leaf to the left leaf so that either
// the right node becomes completely empty or if that's not possible
// the left node is 80% full.
if (fullyMerge) {
// We can fit both nodes into a single node so merge into a single
// node,
TreeLeaf nleaf = (TreeLeaf) UnfreezeNode(lleaf);
byte[] copyBuf = new byte[rleaf.Length];
rleaf.Read(0, copyBuf, 0, copyBuf.Length);
nleaf.Write(nleaf.Length, copyBuf, 0, copyBuf.Length);
// Delete the right node,
DeleteNode(rleaf.Id);
// Setup the merge state
mergeBuffer[0] = nleaf.Id;
mergeBuffer[1] = (long) nleaf.Length;
return 1;
}
// Otherwise, we move bytes from the right leaf into the left
// leaf until it is 80% full,
int toCopy = capacity80 - lleaf.Length;
// Make sure we are copying at least 4 bytes and there are enough
// bytes available in the right leaf to make the copy,
if (toCopy > 4 && rleaf.Length > toCopy) {
// Unfreeze both the nodes,
TreeLeaf mlleaf = (TreeLeaf) UnfreezeNode(lleaf);
TreeLeaf mrleaf = (TreeLeaf) UnfreezeNode(rleaf);
// Copy,
byte[] copyBuf = new byte[toCopy];
mrleaf.Read(0, copyBuf, 0, toCopy);
mlleaf.Write(mlleaf.Length, copyBuf, 0, toCopy);
// Shift the data in the right leaf,
mrleaf.Shift(toCopy, -toCopy);
// Return the merge state
mergeBuffer[0] = mlleaf.Id;
mergeBuffer[1] = (long) mlleaf.Length;
mergeBuffer[2] = rightLeftKey;
mergeBuffer[3] = mrleaf.Id;
mergeBuffer[4] = (long) mrleaf.Length;
return 2;
}
}
} // leaf keys unequal
} else if (leftNode is TreeBranch) {
// Merge branches,
TreeBranch lbranch = (TreeBranch) leftNode;
TreeBranch rbranch = (TreeBranch) rightNode;
int capacity75 = (int) (0.75*MaxBranchSize);
// True if it's possible to full merge left and right into a single
bool fullyMerge = lbranch.ChildCount + rbranch.ChildCount <= MaxBranchSize;
// Only proceed if left is less than 75% full,
if (fullyMerge || lbranch.ChildCount < capacity75) {
// Move elements from the right branch to the left leaf only if the
// branches can be completely merged into a node
if (fullyMerge) {
// We can fit both nodes into a single node so merge into a single
// node,
TreeBranch nbranch = (TreeBranch) UnfreezeNode(lbranch);
// Merge,
nbranch.MergeLeft(rbranch, middleKeyValue, rbranch.ChildCount);
// Delete the right branch,
DeleteNode(rbranch.Id);
// Setup the merge state
mergeBuffer[0] = nbranch.Id;
mergeBuffer[1] = nbranch.LeafElementCount;
return 1;
}
// Otherwise, we move children from the right branch into the left
// branch until it is 75% full,
int toCopy = capacity75 - lbranch.ChildCount;
// Make sure we are copying at least 4 bytes and there are enough
// bytes available in the right leaf to make the copy,
if (toCopy > 2 && rbranch.ChildCount > toCopy + 3) {
// Unfreeze the nodes,
TreeBranch mlbranch = (TreeBranch) UnfreezeNode(lbranch);
TreeBranch mrbranch = (TreeBranch) UnfreezeNode(rbranch);
// And merge
Key newMiddleValue = mlbranch.MergeLeft(mrbranch, middleKeyValue, toCopy);
// Setup and return the merge state
mergeBuffer[0] = mlbranch.Id;
mergeBuffer[1] = mlbranch.LeafElementCount;
mergeBuffer[2] = newMiddleValue;
mergeBuffer[3] = mrbranch.Id;
mergeBuffer[4] = mrbranch.LeafElementCount;
return 2;
}
}
} else {
throw new ApplicationException("Unknown node type.");
}
// Signifies no change to the branch,
return 3;
}
internal void DeleteNode(NodeId nodeId)
{
// If we are deleting a node that's on the temporary node heap, we delete
// it immediately. We know such nodes are only accessed within the scope of
// this transaction so we can free up the resources immediately.
// Is this a heap node?
if (IsHeapNode(nodeId)) {
// Delete it now
NodeHeap.Delete(nodeId);
} else {
// Not a heap node, so we log that this node needs to be deleted when
// we are certain it has gone out of scope of any concurrent transaction
// that may need access to this data.
// Logs a delete operation,
LogStoreChange((byte)0, nodeId);
}
}
private TreeBranch RecurseRebalanceTree(long leftOffset, int height, NodeId nodeId, long absolutePosition, Key inLeftKey)
{
// Put the node in memory,
TreeBranch branch = (TreeBranch) FetchNode(nodeId);
int sz = branch.ChildCount;
int i;
long pos = leftOffset;
// Find the first child i that contains the position.
for (i = 0; i < sz; ++i) {
long childElemCount = branch.GetChildLeafElementCount(i);
// abs position falls within bounds,
if (absolutePosition >= pos &&
absolutePosition < pos + childElemCount) {
break;
}
pos += childElemCount;
}
if (i > 0) {
NodeId leftId = branch.GetChild(i - 1);
NodeId rightId = branch.GetChild(i);
// Only continue if both left and right are on the heap
if (IsHeapNode(leftId) &&
IsHeapNode(rightId) &&
IsHeapNode(nodeId)) {
Key leftKey = (i - 1 == 0)
? inLeftKey
: branch.GetKey(i - 1);
Key rightKey = branch.GetKey(i);
// Perform the merge operation,
Key midKeyValue = rightKey;
object[] mergeBuffer = new Object[5];
int merge_result = MergeNodes(midKeyValue, leftId, rightId,
leftKey, rightKey, mergeBuffer);
if (merge_result == 1) {
branch.SetChild((NodeId) mergeBuffer[0], i - 1);
branch.SetChildLeafElementCount((long) mergeBuffer[1], i - 1);
branch.RemoveChild(i);
}
//
else if (merge_result == 2) {
branch.SetChild((NodeId) mergeBuffer[0], i - 1);
branch.SetChildLeafElementCount((long) mergeBuffer[1], i - 1);
branch.SetKeyToLeft((Key) mergeBuffer[2], i);
branch.SetChild((NodeId) mergeBuffer[3], i);
branch.SetChildLeafElementCount((long) mergeBuffer[4], i);
}
}
}
// After merge, we don't know how the children will be placed, so we
// do another search on the child to descend to,
sz = branch.ChildCount;
pos = leftOffset;
// Find the first child i that contains the position.
for (i = 0; i < sz; ++i) {
long childElemCount = branch.GetChildLeafElementCount(i);
// abs position falls within bounds,
if (absolutePosition >= pos &&
absolutePosition < pos + childElemCount) {
break;
}
pos += childElemCount;
}
// Descend on 'i'
ITreeNode descendChild = FetchNode(branch.GetChild(i));
// Finish if we hit a leaf
if (descendChild is TreeLeaf) {
// End if we hit the leaf,
return branch;
}
Key newLeftKey = (i == 0)
? inLeftKey
: branch.GetKey(i);
// Otherwise recurse on the child,
TreeBranch child_branch =
RecurseRebalanceTree(pos, height + 1,
descendChild.Id, absolutePosition,
newLeftKey);
// Make sure we unfreeze the branch
branch = (TreeBranch) UnfreezeNode(branch);
// Update the child,
branch.SetChild(child_branch.Id, i);
branch.SetChildLeafElementCount(child_branch.LeafElementCount, i);
// And return this branch,
return branch;
}
public VersionInfo(long versionId, NodeId rootNodePointer, long versionInfoRef)
{
this.versionId = versionId;
this.rootNodePointer = rootNodePointer;
this.versionInfoRef = versionInfoRef;
}
private void WrittenNode(ITreeNode node, NodeId nodeId)
{
// Delete the reference to the old node,
DeleteNode(node.Id);
// Log the insert operation.
LogStoreChange((byte) 1, nodeId);
}
private NodeId WriteNode(NodeId nodeId)
{
return ts.WriteNode(nodeId);
}
internal ITreeNode FetchNode(NodeId nodeId)
{
// Is it a node we can fetch from the local node heap?
if (IsHeapNode(nodeId)) {
ITreeNode n = NodeHeap.FetchNode(nodeId);
if (n == null)
throw new NullReferenceException(nodeId.ToString());
return n;
}
// If there's nothing in the prefetch keymap,
if (prefetchKeymap.Count == 0) {
ITreeNode n = treeStore.FetchNodes(new NodeId[] {nodeId})[0];
if (n == null)
throw new NullReferenceException(nodeId.ToString());
return n;
}
List<NodeId> prefetchNodeset = new List<NodeId>();
prefetchNodeset.Add(nodeId);
DiscoverPrefetchNodeSet(prefetchNodeset);
int len = prefetchNodeset.Count;
NodeId[] nodeRefs = new NodeId[len];
for (int i = 0; i < len; ++i) {
nodeRefs[i] = prefetchNodeset[i];
}
{
// Otherwise fetch the node from the tree store
ITreeNode n = treeStore.FetchNodes(nodeRefs)[0];
if (n == null)
throw new NullReferenceException(nodeId.ToString());
return n;
}
}
public PlaceholderLeaf(TreeSystemTransaction ts, NodeId nodeId, int size)
{
this.ts = ts;
this.nodeId = nodeId;
this.size = size;
}
internal bool IsFrozen(NodeId nodeId)
{
return !nodeId.IsInMemory;
// // A node is frozen if either it is in the store (nodeId >= 0) or it has
// // the lock bit set to 0
// return nodeId >= 0 ||
// (nodeId & 0x02000000000000000L) == 0;
}
private void DeleteNode(NodeId nodeId)
{
ts.DeleteNode(nodeId);
}
internal NodeId WriteNode(NodeId nodeId)
{
// Create the sequence,
TreeWrite sequence = new TreeWrite();
// Create the command sequence to write this tree out,
int rootId = PopulateSequence(nodeId, sequence);
if (rootId != -1) {
// Write out this sequence,
IList<NodeId> refs = treeStore.Persist(sequence);
// Update internal structure for each node written,
IList<ITreeNode> nodes = sequence.BranchNodes;
int sz = nodes.Count;
for (int i = 0; i < sz; ++i) {
WrittenNode(nodes[i], refs[i]);
}
int bnodesSz = sz;
nodes = sequence.LeafNodes;
sz = nodes.Count;
for (int i = 0; i < sz; ++i) {
WrittenNode(nodes[i], refs[i + bnodesSz]);
}
// Normalize the pointer,
if (rootId >= TreeWrite.BranchPoint) {
rootId = rootId - TreeWrite.BranchPoint;
} else {
rootId = rootId + bnodesSz;
}
// Return a reference to the node written,
return refs[rootId];
}
return nodeId;
}
private ITreeNode FetchNode(NodeId nodeId)
{
return ts.FetchNode(nodeId);
}
private void ActualDisposeNode(NodeId nodeId)
{
// Dispose of the node,
treeStore.DisposeNode(nodeId);
// And return
}
private bool IsFrozen(NodeId nodeId)
{
return ts.IsFrozen(nodeId);
}
private void DeleteChildTree(int height, NodeId node)
{
if (height == treeHeight) {
// This is a known leaf node,
DeleteNode(node);
return;
}
// Fetch the node,
ITreeNode treeNode = FetchNode(node);
if (treeNode is TreeLeaf) {
// Leaf reached, so set the tree height, delete and return
treeHeight = height;
DeleteNode(node);
return;
}
// The behaviour here changes depending on the system implementation.
// Either we can simply unlink from the entire tree or we need to
// recursely free all the leaf nodes.
if (treeStore.NotifyNodeChanged) {
// Need to account for all nodes so delete the node and all in the
// sub-tree.
DisposeTree(node);
} else {
// Otherwise we can simply unlink the branches on the heap and be
// done with it.
DisposeHeapNodes(node);
}
}
private bool IsHeapNode(NodeId nodeId)
{
return ts.IsHeapNode(nodeId);
}
private void DisposeTree(NodeId id)
{
// It is a heap node, so fetch
ITreeNode node = FetchNode(id);
// Is it a leaf or a branch?
if (node is TreeLeaf) {
// If it's a leaf, dispose it
DeleteNode(id);
// And return,
return;
}
if (node is TreeBranch) {
// This is a branch, so we need to dipose the children if they are heap
TreeBranch branch = (TreeBranch) node;
int sz = branch.ChildCount;
for (int i = 0; i < sz; ++i) {
// Recurse for each child,
DisposeTree(branch.GetChild(i));
}
// Then dispose this,
DeleteNode(id);
// And return,
return;
}
throw new ApplicationException("Unknown node type.");
}
private void StackPush(int childIndex, long offset, NodeId nodeId)
{
if (stackSize + StackFrameSize >= stack.Length) {
// Expand the size of the stack.
// The default size should be plenty for most iterators unless we
// happen to be iterating across a particularly deep B+Tree.
long[] newStack = new long[stack.Length*2];
Array.Copy(stack, 0, newStack, 0, stack.Length);
stack = newStack;
}
stack[stackSize] = childIndex;
stack[stackSize + 1] = offset;
stack[stackSize + 2] = nodeId.High;
stack[stackSize + 3] = nodeId.Low;
stackSize += StackFrameSize;
}
private NodeId FlushNodes(NodeId id, NodeId[] includeIds)
{
if (!IsHeapNode(id))
return id;
// Is this reference in the list?
int c = Array.BinarySearch(includeIds, id);
if (c < 0) {
// It was not found, so go to the children,
// Note that this node will change if it's a branch node, but the
// reference to it will not change.
// It is a heap node, so fetch
ITreeNode node = FetchNode(id);
// Is it a leaf or a branch?
if (node is TreeLeaf)
return id;
if (node is TreeBranch) {
// This is a branch, so we need to write out any children that are on
// the heap before we write out the branch itself,
TreeBranch branch = (TreeBranch) node;
int sz = branch.ChildCount;
for (int i = 0; i < sz; ++i) {
NodeId oldId = branch.GetChild(i);
// Recurse
NodeId newId = FlushNodes(oldId, includeIds);
branch.SetChild(newId, i);
}
// And return the reference
return id;
}
throw new ApplicationException("Unknown node type.");
}
// This node was in the 'includeIds' list so write it out now,
return WriteNode(id);
}
public void SetChildOverride(NodeId childPointer, int n)
{
children[(n * 5) + 0] = childPointer.High;
children[(n * 5) + 1] = childPointer.Low;
}
