public static void DumpHumanReadable(Transaction tx, string path, Page start)
{
using (var writer = File.CreateText(path))
{
var stack = new Stack<Page>();
stack.Push(start);
writer.WriteLine("Root page #{0}",start.PageNumber);
while (stack.Count > 0)
{
var currentPage = stack.Pop();
if (currentPage.IsLeaf)
{
writer.WriteLine();
writer.WriteLine("Page #{0}, NumberOfEntries = {1}, Flags = {2} (Leaf), Used: {3} : {4}", currentPage.PageNumber,currentPage.NumberOfEntries,currentPage.Flags, currentPage.SizeUsed, currentPage.CalcSizeUsed());
if(currentPage.NumberOfEntries <= 0)
writer.WriteLine("Empty page (tree corrupted?)");
for (int nodeIndex = 0; nodeIndex < currentPage.NumberOfEntries;nodeIndex++)
{
var node = currentPage.GetNode(nodeIndex);
var key = currentPage.GetNodeKey(node);
writer.WriteLine("Node #{0}, Flags = {1}, {4} = {2}, Key = {3}, Entry Size: {5}", nodeIndex, node->Flags, node->DataSize, MaxString(key.ToString(), 25), node->Flags == NodeFlags.Data ? "Size" : "Page",
SizeOf.NodeEntry(node));
}
writer.WriteLine();
}
else if(currentPage.IsBranch)
{
writer.WriteLine();
writer.WriteLine("Page #{0}, NumberOfEntries = {1}, Flags = {2} (Branch), Used: {3} : {4}", currentPage.PageNumber, currentPage.NumberOfEntries, currentPage.Flags, currentPage.SizeUsed, currentPage.SizeUsed);
var key = new Slice(SliceOptions.Key);
for (int nodeIndex = 0; nodeIndex < currentPage.NumberOfEntries; nodeIndex++)
{
var node = currentPage.GetNode(nodeIndex);
writer.WriteLine("Node #{2}, {0} / to page #{1}, Entry Size: {3}", GetBranchNodeString(nodeIndex, key, currentPage, node), node->PageNumber, nodeIndex,
SizeOf.NodeEntry(node));
}
for (int nodeIndex = 0; nodeIndex < currentPage.NumberOfEntries; nodeIndex++)
{
var node = currentPage.GetNode(nodeIndex);
if (node->PageNumber < 0 || node->PageNumber > tx.State.NextPageNumber)
{
writer.Write("Found invalid reference to page #{0}", currentPage.PageNumber);
stack.Clear();
break;
}
var child = tx.GetReadOnlyPage(node->PageNumber);
stack.Push(child);
}
writer.WriteLine();
}
}
}
}
public PageSplitter(Transaction tx,
Tree tree,
SliceComparer cmp,
Slice newKey,
int len,
long pageNumber,
NodeFlags nodeType,
ushort nodeVersion,
Cursor cursor,
TreeMutableState treeState)
{
_tx = tx;
_tree = tree;
_cmp = cmp;
_newKey = newKey;
_len = len;
_pageNumber = pageNumber;
_nodeType = nodeType;
_nodeVersion = nodeVersion;
_cursor = cursor;
_treeState = treeState;
Page page = _cursor.Pages.First.Value;
_page = tx.ModifyPage(page.PageNumber, page);
_cursor.Pop();
}
public byte* Execute()
{
Page rightPage = Tree.NewPage(_tx, _page.Flags, 1);
_treeState.RecordNewPage(_page, 1);
rightPage.Flags = _page.Flags;
if (_cursor.PageCount == 0) // we need to do a root split
{
Page newRootPage = Tree.NewPage(_tx, PageFlags.Branch, 1);
_cursor.Push(newRootPage);
_treeState.RootPageNumber = newRootPage.PageNumber;
_treeState.Depth++;
_treeState.RecordNewPage(newRootPage, 1);
// now add implicit left page
newRootPage.AddPageRefNode(0, Slice.BeforeAllKeys, _page.PageNumber);
_parentPage = newRootPage;
_parentPage.LastSearchPosition++;
}
else
{
// we already popped the page, so the current one on the stack is what the parent of the page
_parentPage = _tx.ModifyPage(_cursor.CurrentPage.PageNumber, _cursor.CurrentPage);
_cursor.Update(_cursor.Pages.First, _parentPage);
}
if (_page.IsLeaf)
{
_tx.ClearRecentFoundPages(_tree);
}
if (_page.LastSearchPosition >= _page.NumberOfEntries)
{
// when we get a split at the end of the page, we take that as a hint that the user is doing
// sequential inserts, at that point, we are going to keep the current page as is and create a new
// page, this will allow us to do minimal amount of work to get the best density
byte* pos;
if (_page.IsBranch)
{
// here we steal the last entry from the current page so we maintain the implicit null left entry
NodeHeader* node = _page.GetNode(_page.NumberOfEntries - 1);
Debug.Assert(node->Flags == NodeFlags.PageRef);
rightPage.AddPageRefNode(0, Slice.Empty, node->PageNumber);
pos = AddNodeToPage(rightPage, 1);
AddSeparatorToParentPage(rightPage, new Slice(node));
_page.RemoveNode(_page.NumberOfEntries - 1);
}
else
{
AddSeparatorToParentPage(rightPage, _newKey);
pos = AddNodeToPage(rightPage, 0);
}
_cursor.Push(rightPage);
return pos;
}
return SplitPageInHalf(rightPage);
}
public override int Write(Page page, long? pageNumber)
{
var toWrite = page.IsOverflow ? GetNumberOfOverflowPages(page.OverflowSize) : 1;
var requestedPageNumber = pageNumber ?? page.PageNumber;
return WriteDirect(page, requestedPageNumber, toWrite);
}
public byte* AddSeparator(MemorySlice separator, long pageRefNumber, int? nodePos = null)
{
var originalLastSearchPositionOfParent = _parentPage.LastSearchPosition;
if (nodePos == null)
nodePos = _parentPage.NodePositionFor(separator); // select the appropriate place for this
var separatorKeyToInsert = _parentPage.PrepareKeyToInsert(separator, nodePos.Value);
if (_parentPage.HasSpaceFor(_tx, SizeOf.BranchEntry(separatorKeyToInsert) + Constants.NodeOffsetSize + SizeOf.NewPrefix(separatorKeyToInsert)) == false)
{
var pageSplitter = new PageSplitter(_tx, _tree, separator, -1, pageRefNumber, NodeFlags.PageRef, 0, _cursor, _tree.State);
var posToInsert = pageSplitter.Execute();
ParentOfAddedPageRef = _cursor.CurrentPage;
var adjustParentPageOnCursor = true;
for (int i = 0; i < _cursor.CurrentPage.NumberOfEntries; i++)
{
if (_cursor.CurrentPage.GetNode(i)->PageNumber == _currentPage.PageNumber)
{
adjustParentPageOnCursor = false;
_cursor.CurrentPage.LastSearchPosition = i;
break;
}
}
if (adjustParentPageOnCursor)
{
// the above page split has modified the cursor that its first page points to the parent of the leaf where 'separatorKey' was inserted
// and it doesn't have the reference to _page, we need to ensure that the actual parent is first at the cursor
_cursor.Pop();
_cursor.Push(_parentPage);
EnsureValidLastSearchPosition(_parentPage, _currentPage.PageNumber, originalLastSearchPositionOfParent);
}
#if VALIDATE
Debug.Assert(_cursor.CurrentPage.GetNode(_cursor.CurrentPage.LastSearchPosition)->PageNumber == _currentPage.PageNumber,
"The parent page is not referencing a page which is being split");
var parentToValidate = ParentOfAddedPageRef;
Debug.Assert(Enumerable.Range(0, parentToValidate.NumberOfEntries).Any(i => parentToValidate.GetNode(i)->PageNumber == pageRefNumber),
"The parent page of a page reference isn't referencing it");
#endif
return posToInsert;
}
ParentOfAddedPageRef = _parentPage;
var pos = _parentPage.AddPageRefNode(nodePos.Value, separatorKeyToInsert, pageRefNumber);
EnsureValidLastSearchPosition(_parentPage, _currentPage.PageNumber, originalLastSearchPositionOfParent);
return pos;
}
public FoundPage(long number, Page page, MemorySlice firstKey, MemorySlice lastKey, long[] cursorPath)
{
Number = number;
Page = page;
FirstKey = firstKey;
LastKey = lastKey;
CursorPath = cursorPath;
}
public ParentPageAction(Page parentPage, Page currentPage, Tree tree, Cursor cursor, Transaction tx)
{
_parentPage = parentPage;
_currentPage = currentPage;
_tree = tree;
_cursor = cursor;
_tx = tx;
}
public override int Write(Page page, long? pageNumber)
{
long startPage = pageNumber ?? page.PageNumber;
//note: GetNumberOfOverflowPages and WriteDirect can throw ObjectDisposedException if the pager is already disposed
int toWrite = page.IsOverflow ? GetNumberOfOverflowPages(page.OverflowSize) : 1;
return WriteDirect(page, startPage, toWrite);
}
public static unsafe bool HasDuplicateBranchReferences(Transaction tx, Page start,out long pageNumberWithDuplicates)
{
var stack = new Stack<Page>();
var existingTreeReferences = new ConcurrentDictionary<long, List<long>>();
stack.Push(start);
while (stack.Count > 0)
{
var currentPage = stack.Pop();
if (currentPage.IsBranch)
{
for (int nodeIndex = 0; nodeIndex < currentPage.NumberOfEntries; nodeIndex++)
{
var node = currentPage.GetNode(nodeIndex);
existingTreeReferences.AddOrUpdate(currentPage.PageNumber, new List<long> { node->PageNumber },
(branchPageNumber, pageNumberReferences) =>
{
pageNumberReferences.Add(node->PageNumber);
return pageNumberReferences;
});
}
for (int nodeIndex = 0; nodeIndex < currentPage.NumberOfEntries; nodeIndex++)
{
var node = currentPage.GetNode(nodeIndex);
if (node->PageNumber < 0 || node->PageNumber > tx.State.NextPageNumber)
{
throw new InvalidDataException("found invalid reference on branch - tree is corrupted");
}
var child = tx.GetReadOnlyPage(node->PageNumber);
stack.Push(child);
}
}
}
Func<long, HashSet<long>> relevantPageReferences =
branchPageNumber => new HashSet<long>(existingTreeReferences
.Where(kvp => kvp.Key != branchPageNumber)
.SelectMany(kvp => kvp.Value));
// ReSharper disable once LoopCanBeConvertedToQuery
foreach (var branchReferences in existingTreeReferences)
{
if (
branchReferences.Value.Any(
referencePageNumber => relevantPageReferences(branchReferences.Key).Contains(referencePageNumber)))
{
pageNumberWithDuplicates = branchReferences.Key;
return true;
}
}
pageNumberWithDuplicates = -1;
return false;
}
public bool Seek(Slice key)
{
Lazy<Cursor> lazy;
_currentPage = _tree.FindPageFor(_tx, key, out lazy);
_cursor = lazy.Value;
_cursor.Pop();
var node = _currentPage.Search(key, _cmp);
if (node == null)
{
return false;
}
_currentKey.Set(node);
return this.ValidateCurrentKey(Current, _cmp);
}
public void RecordNewPage(Page p, int num)
{
PageCount += num;
if (p.IsBranch)
{
BranchPages++;
}
else if (p.IsLeaf)
{
LeafPages++;
}
else if (p.IsOverflow)
{
OverflowPages += num;
}
}
public void RecordNewPage(Page p, int num)
{
PageCount++;
var flags = p.Flags;
if ((flags & PageFlags.Branch) == PageFlags.Branch)
{
BranchPages++;
}
else if ((flags & PageFlags.Leaf) == PageFlags.Leaf)
{
LeafPages++;
}
else if ((flags & PageFlags.Overflow) == PageFlags.Overflow)
{
OverflowPages += num;
}
}
public void Update(LinkedListNode<Page> node, Page newVal)
{
var oldPageNumber = node.Value.PageNumber;
var newPageNumber = newVal.PageNumber;
if (oldPageNumber == newPageNumber)
{
_pagesByNum[oldPageNumber] = newVal;
node.Value = newVal;
return;
}
_anyOverrides = true;
_pagesByNum[oldPageNumber] = newVal;
_pagesByNum.Add(newPageNumber, newVal);
node.Value = newVal;
}
public bool Seek(Slice key)
{
Lazy<Cursor> lazy;
_currentPage = _tree.FindPageFor(key, out lazy);
_cursor = lazy.Value;
_cursor.Pop();
var node = _currentPage.Search(key);
if (node != null)
{
_currentKey.Set(node);
return this.ValidateCurrentKey(Current);
}
// The key is not found in the db, but we are Seek()ing for equals or starts with.
// We know that the exact value isn't there, but it is possible that the next page has values
// that is actually greater than the key, so we need to check it as well.
_currentPage.LastSearchPosition = _currentPage.NumberOfEntries; // force next MoveNext to move to the next _page_.
return MoveNext();
}
public void RecordFreedPage(Page p, int num)
{
PageCount -= num;
Debug.Assert(PageCount >= 0);
if (p.IsBranch)
{
BranchPages--;
Debug.Assert(BranchPages >= 0);
}
else if (p.IsLeaf)
{
LeafPages--;
Debug.Assert(LeafPages >= 0);
}
else if (p.IsOverflow)
{
OverflowPages -= num;
Debug.Assert(OverflowPages >= 0);
}
}
public abstract int Write(Page page, long? pageNumber);
public abstract int WriteDirect(Page start, long pagePosition, int pagesToWrite);
public IIterator MultiRead(Slice key)
{
Lazy<Cursor> lazy;
var page = FindPageFor(key, out lazy);
if (page == null || page.LastMatch != 0)
{
return new EmptyIterator();
}
var item = page.Search(key);
var fetchedNodeKey = new Slice(item);
if (fetchedNodeKey.Compare(key) != 0)
{
throw new InvalidDataException("Was unable to retrieve the correct node. Data corruption possible");
}
if (item->Flags == NodeFlags.MultiValuePageRef)
{
var tree = OpenOrCreateMultiValueTree(_tx, key, item);
return tree.Iterate();
}
var nestedPage = new Page(NodeHeader.DirectAccess(_tx, item), "multi tree", (ushort)NodeHeader.GetDataSize(_tx, item));
return new PageIterator(nestedPage);
}
public void MultiAdd(Slice key, Slice value, ushort? version = null)
{
if (value == null) throw new ArgumentNullException("value");
int maxNodeSize = _tx.DataPager.MaxNodeSize;
if (value.Size > maxNodeSize)
throw new ArgumentException(
"Cannot add a value to child tree that is over " + maxNodeSize + " bytes in size", "value");
if (value.Size == 0)
throw new ArgumentException("Cannot add empty value to child tree");
State.IsModified = true;
Lazy<Cursor> lazy;
var page = FindPageFor(key, out lazy);
if ((page == null || page.LastMatch != 0))
{
MultiAddOnNewValue(_tx, key, value, version, maxNodeSize);
return;
}
page = _tx.ModifyPage(page.PageNumber, page);
var item = page.GetNode(page.LastSearchPosition);
// already was turned into a multi tree, not much to do here
if (item->Flags == NodeFlags.MultiValuePageRef)
{
var existingTree = OpenOrCreateMultiValueTree(_tx, key, item);
existingTree.DirectAdd(value, 0, version: version);
return;
}
byte* nestedPagePtr;
if (item->Flags == NodeFlags.PageRef)
{
var overFlowPage = _tx.ModifyPage(item->PageNumber, null);
nestedPagePtr = overFlowPage.Base + Constants.PageHeaderSize;
}
else
{
nestedPagePtr = NodeHeader.DirectAccess(_tx, item);
}
var nestedPage = new Page(nestedPagePtr, "multi tree", (ushort)NodeHeader.GetDataSize(_tx, item));
var existingItem = nestedPage.Search(value);
if (nestedPage.LastMatch != 0)
existingItem = null;// not an actual match, just greater than
ushort previousNodeRevision = existingItem != null ? existingItem->Version : (ushort)0;
CheckConcurrency(key, value, version, previousNodeRevision, TreeActionType.Add);
if (existingItem != null)
{
// maybe same value added twice?
var tmpKey = new Slice(item);
if (tmpKey.Compare(value) == 0)
return; // already there, turning into a no-op
nestedPage.RemoveNode(nestedPage.LastSearchPosition);
}
if (nestedPage.HasSpaceFor(_tx, value, 0))
{
// we are now working on top of the modified root page, we can just modify the memory directly
nestedPage.AddDataNode(nestedPage.LastSearchPosition, value, 0, previousNodeRevision);
return;
}
int pageSize = nestedPage.CalcSizeUsed() + Constants.PageHeaderSize;
var newRequiredSize = pageSize + nestedPage.GetRequiredSpace(value, 0);
if (newRequiredSize <= maxNodeSize)
{
// we can just expand the current value... no need to create a nested tree yet
var actualPageSize = (ushort)Math.Min(Utils.NearestPowerOfTwo(newRequiredSize), maxNodeSize);
ExpandMultiTreeNestedPageSize(_tx, key, value, nestedPagePtr, actualPageSize, item->DataSize);
return;
}
// we now have to convert this into a tree instance, instead of just a nested page
var tree = Create(_tx, TreeFlags.MultiValue);
for (int i = 0; i < nestedPage.NumberOfEntries; i++)
{
var existingValue = nestedPage.GetNodeKey(i);
tree.DirectAdd(existingValue, 0);
}
tree.DirectAdd(value, 0, version: version);
_tx.AddMultiValueTree(this, key, tree);
// we need to record that we switched to tree mode here, so the next call wouldn't also try to create the tree again
DirectAdd(key, sizeof (TreeRootHeader), NodeFlags.MultiValuePageRef);
}
private void MultiAddOnNewValue(Transaction tx, Slice key, Slice value, ushort? version, int maxNodeSize)
{
var requiredPageSize = Constants.PageHeaderSize + SizeOf.LeafEntry(-1, value, 0) + Constants.NodeOffsetSize;
if (requiredPageSize > maxNodeSize)
{
// no choice, very big value, we might as well just put it in its own tree from the get go...
// otherwise, we would have to put this in overflow page, and that won't save us any space anyway
var tree = Create(tx, TreeFlags.MultiValue);
tree.DirectAdd(value, 0);
tx.AddMultiValueTree(this, key, tree);
DirectAdd(key, sizeof (TreeRootHeader), NodeFlags.MultiValuePageRef);
return;
}
var actualPageSize = (ushort) Math.Min(Utils.NearestPowerOfTwo(requiredPageSize), maxNodeSize);
var ptr = DirectAdd(key, actualPageSize);
var nestedPage = new Page(ptr, "multi tree", actualPageSize)
{
PageNumber = -1L,// hint that this is an inner page
Lower = (ushort) Constants.PageHeaderSize,
Upper = actualPageSize,
Flags = PageFlags.Leaf,
};
CheckConcurrency(key, value, version, 0, TreeActionType.Add);
nestedPage.AddDataNode(0, value, 0, 0);
}
public void MultiDelete(Slice key, Slice value, ushort? version = null)
{
State.IsModified = true;
Lazy<Cursor> lazy;
var page = FindPageFor(key, out lazy);
if (page == null || page.LastMatch != 0)
{
return; //nothing to delete - key not found
}
page = _tx.ModifyPage(page.PageNumber, page);
var item = page.GetNode(page.LastSearchPosition);
if (item->Flags == NodeFlags.MultiValuePageRef) //multi-value tree exists
{
var tree = OpenOrCreateMultiValueTree(_tx, key, item);
tree.Delete(value, version);
// previously, we would convert back to a simple model if we dropped to a single entry
// however, it doesn't really make sense, once you got enough values to go to an actual nested
// tree, you are probably going to remain that way, or be removed completely.
if (tree.State.EntriesCount != 0)
return;
_tx.TryRemoveMultiValueTree(this, key);
_tx.FreePage(tree.State.RootPageNumber);
Delete(key);
}
else // we use a nested page here
{
var nestedPage = new Page(NodeHeader.DirectAccess(_tx, item), "multi tree", (ushort)NodeHeader.GetDataSize(_tx, item));
var nestedItem = nestedPage.Search(value);
if (nestedItem == null) // value not found
return;
byte* nestedPagePtr;
if (item->Flags == NodeFlags.PageRef)
{
var overFlowPage = _tx.ModifyPage(item->PageNumber, null);
nestedPagePtr = overFlowPage.Base + Constants.PageHeaderSize;
}
else
{
nestedPagePtr = NodeHeader.DirectAccess(_tx, item);
}
nestedPage = new Page(nestedPagePtr, "multi tree", (ushort)NodeHeader.GetDataSize(_tx, item))
{
LastSearchPosition = nestedPage.LastSearchPosition
};
CheckConcurrency(key, value, version, nestedItem->Version, TreeActionType.Delete);
nestedPage.RemoveNode(nestedPage.LastSearchPosition);
if (nestedPage.NumberOfEntries == 0)
Delete(key);
}
}
private void ExpandMultiTreeNestedPageSize(Transaction tx, Slice key, Slice value, byte* nestedPagePtr, ushort newSize, int currentSize)
{
Debug.Assert(newSize > currentSize);
TemporaryPage tmp;
using (tx.Environment.GetTemporaryPage(tx, out tmp))
{
var tempPagePointer = tmp.TempPagePointer;
NativeMethods.memcpy(tempPagePointer, nestedPagePtr, currentSize);
Delete(key); // release our current page
Page nestedPage = new Page(tempPagePointer, "multi tree", (ushort)currentSize);
var ptr = DirectAdd(key, newSize);
var newNestedPage = new Page(ptr, "multi tree", newSize)
{
Lower = (ushort)Constants.PageHeaderSize,
Upper = newSize,
Flags = PageFlags.Leaf,
PageNumber = -1L // mark as invalid page number
};
Slice nodeKey = new Slice(SliceOptions.Key);
for (int i = 0; i < nestedPage.NumberOfEntries; i++)
{
var nodeHeader = nestedPage.GetNode(i);
nodeKey.Set(nodeHeader);
newNestedPage.AddDataNode(i, nodeKey, 0,
(ushort)(nodeHeader->Version - 1)); // we dec by one because AdddataNode will inc by one, and we don't want to change those values
}
newNestedPage.Search(value);
newNestedPage.AddDataNode(newNestedPage.LastSearchPosition, value, 0, 0);
}
}
public void MultiAdd(Slice key, Slice value, ushort?version = null)
{
if (value == null)
{
throw new ArgumentNullException("value");
}
int maxNodeSize = _tx.DataPager.MaxNodeSize;
if (value.Size > maxNodeSize)
{
throw new ArgumentException(
"Cannot add a value to child tree that is over " + maxNodeSize + " bytes in size", "value");
}
if (value.Size == 0)
{
throw new ArgumentException("Cannot add empty value to child tree");
}
State.IsModified = true;
Lazy <Cursor> lazy;
var page = FindPageFor(key, out lazy);
if ((page == null || page.LastMatch != 0))
{
MultiAddOnNewValue(_tx, key, value, version, maxNodeSize);
return;
}
page = _tx.ModifyPage(page.PageNumber, page);
var item = page.GetNode(page.LastSearchPosition);
// already was turned into a multi tree, not much to do here
if (item->Flags == NodeFlags.MultiValuePageRef)
{
var existingTree = OpenOrCreateMultiValueTree(_tx, key, item);
existingTree.DirectAdd(value, 0, version: version);
return;
}
byte *nestedPagePtr;
if (item->Flags == NodeFlags.PageRef)
{
var overFlowPage = _tx.ModifyPage(item->PageNumber, null);
nestedPagePtr = overFlowPage.Base + Constants.PageHeaderSize;
}
else
{
nestedPagePtr = NodeHeader.DirectAccess(_tx, item);
}
var nestedPage = new Page(nestedPagePtr, "multi tree", (ushort)NodeHeader.GetDataSize(_tx, item));
var existingItem = nestedPage.Search(value);
if (nestedPage.LastMatch != 0)
{
existingItem = null; // not an actual match, just greater than
}
ushort previousNodeRevision = existingItem != null ? existingItem->Version : (ushort)0;
CheckConcurrency(key, value, version, previousNodeRevision, TreeActionType.Add);
if (existingItem != null)
{
// maybe same value added twice?
var tmpKey = new Slice(item);
if (tmpKey.Compare(value) == 0)
{
return; // already there, turning into a no-op
}
nestedPage.RemoveNode(nestedPage.LastSearchPosition);
}
if (nestedPage.HasSpaceFor(_tx, value, 0))
{
// we are now working on top of the modified root page, we can just modify the memory directly
nestedPage.AddDataNode(nestedPage.LastSearchPosition, value, 0, previousNodeRevision);
return;
}
int pageSize = nestedPage.CalcSizeUsed() + Constants.PageHeaderSize;
var newRequiredSize = pageSize + nestedPage.GetRequiredSpace(value, 0);
if (newRequiredSize <= maxNodeSize)
{
// we can just expand the current value... no need to create a nested tree yet
var actualPageSize = (ushort)Math.Min(Utils.NearestPowerOfTwo(newRequiredSize), maxNodeSize);
ExpandMultiTreeNestedPageSize(_tx, key, value, nestedPagePtr, actualPageSize, item->DataSize);
return;
}
// we now have to convert this into a tree instance, instead of just a nested page
var tree = Create(_tx, TreeFlags.MultiValue);
for (int i = 0; i < nestedPage.NumberOfEntries; i++)
{
var existingValue = nestedPage.GetNodeKey(i);
tree.DirectAdd(existingValue, 0);
}
tree.DirectAdd(value, 0, version: version);
_tx.AddMultiValueTree(this, key, tree);
// we need to record that we switched to tree mode here, so the next call wouldn't also try to create the tree again
DirectAdd(key, sizeof(TreeRootHeader), NodeFlags.MultiValuePageRef);
}
public override int Write(Page page, long? pageNumber)
{
long startPage = pageNumber ?? page.PageNumber;
int toWrite = page.IsOverflow ? GetNumberOfOverflowPages(page.OverflowSize) : 1;
return WriteDirect(page, startPage, toWrite);
}
private void WritePageDirect(Page page, int numberOfPagesIncludingOverflow)
{
var pageFromScratchBuffer = _env.ScratchBufferPool.Allocate(this, numberOfPagesIncludingOverflow);
var dest = _env.ScratchBufferPool.AcquirePagePointer(pageFromScratchBuffer.ScratchFileNumber, pageFromScratchBuffer.PositionInScratchBuffer);
Memory.Copy(dest, page.Base, numberOfPagesIncludingOverflow * AbstractPager.PageSize);
_allocatedPagesInTransaction++;
_dirtyPages.Add(page.PageNumber);
page.Dirty = true;
if (numberOfPagesIncludingOverflow > 1)
_dirtyOverflowPages.Add(page.PageNumber + 1, numberOfPagesIncludingOverflow - 1);
_scratchPagesTable[page.PageNumber] = pageFromScratchBuffer;
_transactionPages.Add(pageFromScratchBuffer);
}
public bool MovePrev()
{
while (true)
{
_currentPage.LastSearchPosition--;
if (_currentPage.LastSearchPosition >= 0)
{
// run out of entries, need to select the next page...
while (_currentPage.IsBranch)
{
_cursor.Push(_currentPage);
var node = _currentPage.GetNode(_currentPage.LastSearchPosition);
_currentPage = _tx.GetReadOnlyPage(node->PageNumber);
_currentPage.LastSearchPosition = _currentPage.NumberOfEntries - 1;
}
var current = _currentPage.GetNode(_currentPage.LastSearchPosition);
if (this.ValidateCurrentKey(current) == false)
return false;
_currentKey.Set(current);
return true;// there is another entry in this page
}
if (_cursor.PageCount == 0)
break;
_currentPage = _cursor.Pop();
}
_currentPage = null;
return false;
}
internal void WriteDirect(Page[] pages, long nextPageNumber)
{
for (int i = 0; i < pages.Length; i++)
{
int numberOfPages = 1;
var page = pages[i];
if (page.IsOverflow)
{
numberOfPages = (page.OverflowSize / AbstractPager.PageSize) + (page.OverflowSize % AbstractPager.PageSize == 0 ? 0 : 1);
i += numberOfPages;
_overflowPagesInTransaction += (numberOfPages - 1);
}
WritePageDirect(page, numberOfPages);
}
}
private void RebalanceRoot(Page page)
{
if (page.NumberOfEntries == 0)
return; // nothing to do
if (!page.IsBranch || page.NumberOfEntries > 1)
{
return; // cannot do anything here
}
// in this case, we have a root pointer with just one pointer, we can just swap it out
var node = page.GetNode(0);
Debug.Assert(node->Flags == (NodeFlags.PageRef));
_tree.State.LeafPages = 1;
_tree.State.BranchPages = 0;
_tree.State.Depth = 1;
_tree.State.PageCount = 1;
var rootPage = _tx.ModifyPage(node->PageNumber, _tree, null);
_tree.State.RootPageNumber = rootPage.PageNumber;
Debug.Assert(rootPage.Dirty);
_cursor.Pop();
_cursor.Push(rootPage);
_tx.FreePage(page.PageNumber);
}
internal Page ModifyPage(long num, Tree tree, Page page)
{
_env.AssertFlushingNotFailed();
page = page ?? GetReadOnlyPage(num);
if (page.Dirty)
return page;
if (_dirtyPages.Contains(num))
{
page.Dirty = true;
return page;
}
var newPage = AllocatePage(1, PageFlags.None, num); // allocate new page in a log file but with the same number
Memory.Copy(newPage.Base, page.Base, AbstractPager.PageSize);
newPage.LastSearchPosition = page.LastSearchPosition;
newPage.LastMatch = page.LastMatch;
tree.RecentlyFoundPages.Reset(num);
return newPage;
}
public void Push(Page p)
{
Pages.AddFirst(p);
_pagesByNum.Add(p.PageNumber, p);
}
public override int WriteDirect(Page start, long pagePosition, int pagesToWrite)
{
ThrowObjectDisposedIfNeeded();
int toCopy = pagesToWrite*PageSize;
StdLib.memcpy(PagerState.MapBase + pagePosition*PageSize, start.Base, toCopy);
return toCopy;
}
public void MultiDelete(Slice key, Slice value, ushort?version = null)
{
State.IsModified = true;
Lazy <Cursor> lazy;
var page = FindPageFor(key, out lazy);
if (page == null || page.LastMatch != 0)
{
return; //nothing to delete - key not found
}
page = _tx.ModifyPage(page.PageNumber, page);
var item = page.GetNode(page.LastSearchPosition);
if (item->Flags == NodeFlags.MultiValuePageRef) //multi-value tree exists
{
var tree = OpenOrCreateMultiValueTree(_tx, key, item);
tree.Delete(value, version);
// previously, we would convert back to a simple model if we dropped to a single entry
// however, it doesn't really make sense, once you got enough values to go to an actual nested
// tree, you are probably going to remain that way, or be removed completely.
if (tree.State.EntriesCount != 0)
{
return;
}
_tx.TryRemoveMultiValueTree(this, key);
_tx.FreePage(tree.State.RootPageNumber);
Delete(key);
}
else // we use a nested page here
{
var nestedPage = new Page(NodeHeader.DirectAccess(_tx, item), "multi tree", (ushort)NodeHeader.GetDataSize(_tx, item));
var nestedItem = nestedPage.Search(value);
if (nestedItem == null) // value not found
{
return;
}
byte *nestedPagePtr;
if (item->Flags == NodeFlags.PageRef)
{
var overFlowPage = _tx.ModifyPage(item->PageNumber, null);
nestedPagePtr = overFlowPage.Base + Constants.PageHeaderSize;
}
else
{
nestedPagePtr = NodeHeader.DirectAccess(_tx, item);
}
nestedPage = new Page(nestedPagePtr, "multi tree", (ushort)NodeHeader.GetDataSize(_tx, item))
{
LastSearchPosition = nestedPage.LastSearchPosition
};
CheckConcurrency(key, value, version, nestedItem->Version, TreeActionType.Delete);
nestedPage.RemoveNode(nestedPage.LastSearchPosition);
if (nestedPage.NumberOfEntries == 0)
{
Delete(key);
}
}
}
