private bool TryMergePages(TreePage parentPage, TreePage left, TreePage right)
{
TemporaryPage tmp;
using (_tx.Environment.GetTemporaryPage(_tx, out tmp))
{
var mergedPage = tmp.GetTempPage();
Memory.Copy(mergedPage.Base, left.Base, left.PageSize);
var previousSearchPosition = right.LastSearchPosition;
for (int i = 0; i < right.NumberOfEntries; i++)
{
right.LastSearchPosition = i;
var key = GetActualKey(right, right.LastSearchPositionOrLastEntry);
var node = right.GetNode(i);
if (mergedPage.HasSpaceFor(_tx, TreeSizeOf.NodeEntryWithAnotherKey(node, key) + Constants.NodeOffsetSize) == false)
{
right.LastSearchPosition = previousSearchPosition; //previous position --> prevent mutation of parameter
return(false);
}
mergedPage.CopyNodeDataToEndOfPage(node, key);
}
Memory.Copy(left.Base, mergedPage.Base, left.PageSize);
}
parentPage.RemoveNode(parentPage.LastSearchPositionOrLastEntry); // unlink the right sibling
_tree.FreePage(right);
return(true);
}
private void RemoveLeafNode(TreePage page)
{
var node = page.GetNode(page.LastSearchPosition);
if (node->Flags == (TreeNodeFlags.PageRef)) // this is an overflow pointer
{
var overflowPage = GetReadOnlyTreePage(node->PageNumber);
FreePage(overflowPage);
}
page.RemoveNode(page.LastSearchPosition);
}
private byte *OptimizedOnlyMoveNewValueToTheRightPage(TreePage rightPage)
{
// 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
TreePage branchOfSeparator;
byte *pos;
if (_page.IsBranch)
{
if (_page.NumberOfEntries > 2)
{
// here we steal the last entry from the current page so we maintain the implicit null left entry
TreeNodeHeader *node = _page.GetNode(_page.NumberOfEntries - 1);
Debug.Assert(node->Flags == TreeNodeFlags.PageRef);
rightPage.AddPageRefNode(0, Slices.BeforeAllKeys, node->PageNumber);
pos = AddNodeToPage(rightPage, 1);
Slice separatorKey;
using (TreeNodeHeader.ToSlicePtr(_tx.Allocator, node, out separatorKey))
{
AddSeparatorToParentPage(rightPage.PageNumber, separatorKey, out branchOfSeparator);
}
_page.RemoveNode(_page.NumberOfEntries - 1);
}
else
{
_tree.FreePage(rightPage); // return the unnecessary right page
pos = AddSeparatorToParentPage(_pageNumber, _newKey, out branchOfSeparator);
if (_cursor.CurrentPage.PageNumber != branchOfSeparator.PageNumber)
{
_cursor.Push(branchOfSeparator);
}
return(pos);
}
}
else
{
AddSeparatorToParentPage(rightPage.PageNumber, _newKey, out branchOfSeparator);
pos = AddNodeToPage(rightPage, 0);
}
_cursor.Push(rightPage);
return(pos);
}
public void MultiAdd(Slice key, Slice value)
{
if (!value.HasValue)
{
throw new ArgumentNullException(nameof(value));
}
int maxNodeSize = Llt.DataPager.NodeMaxSize;
if (value.Size > maxNodeSize)
{
throw new ArgumentException("Cannot add a value to child tree that is over " + maxNodeSize + " bytes in size", nameof(value));
}
if (value.Size == 0)
{
throw new ArgumentException("Cannot add empty value to child tree");
}
State.IsModified = true;
State.Flags |= TreeFlags.MultiValueTrees;
TreeNodeHeader *node;
var page = FindPageFor(key, out node);
if (page == null || page.LastMatch != 0)
{
MultiAddOnNewValue(key, value, maxNodeSize);
return;
}
page = ModifyPage(page);
var item = page.GetNode(page.LastSearchPosition);
byte *_;
// already was turned into a multi tree, not much to do here
if (item->Flags == TreeNodeFlags.MultiValuePageRef)
{
var existingTree = OpenMultiValueTree(key, item);
existingTree.DirectAdd(value, 0, out _).Dispose();
return;
}
if (item->Flags == TreeNodeFlags.PageRef)
{
throw new InvalidOperationException("Multi trees don't use overflows");
}
var nestedPagePtr = DirectAccessFromHeader(item);
var nestedPage = new TreePage(nestedPagePtr, (ushort)GetDataSize(item));
var existingItem = nestedPage.Search(_llt, value);
if (nestedPage.LastMatch != 0)
{
existingItem = null;// not an actual match, just greater than
}
if (existingItem != null)
{
// maybe same value added twice?
Slice tmpKey;
using (TreeNodeHeader.ToSlicePtr(_llt.Allocator, item, out tmpKey))
{
if (SliceComparer.Equals(tmpKey, value))
{
return; // already there, turning into a no-op
}
}
nestedPage.RemoveNode(nestedPage.LastSearchPosition);
}
if (nestedPage.HasSpaceFor(_llt, 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);
return;
}
if (page.HasSpaceFor(_llt, value, 0))
{
// page has space for an additional node in nested page ...
var requiredSpace = nestedPage.PageSize + // existing page
nestedPage.GetRequiredSpace(value, 0); // new node
if (requiredSpace + Constants.Tree.NodeHeaderSize <= maxNodeSize)
{
// ... and it won't require to create an overflow, so we can just expand the current value, no need to create a nested tree yet
EnsureNestedPagePointer(page, item, ref nestedPage, ref nestedPagePtr);
var newPageSize = (ushort)Math.Min(Bits.NextPowerOf2(requiredSpace), maxNodeSize - Constants.Tree.NodeHeaderSize);
ExpandMultiTreeNestedPageSize(key, value, nestedPagePtr, newPageSize, nestedPage.PageSize);
return;
}
}
EnsureNestedPagePointer(page, item, ref nestedPage, ref nestedPagePtr);
// we now have to convert this into a tree instance, instead of just a nested page
var tree = Create(_llt, _tx, key, TreeFlags.MultiValue);
for (int i = 0; i < nestedPage.NumberOfEntries; i++)
{
Slice existingValue;
using (nestedPage.GetNodeKey(_llt, i, out existingValue))
{
tree.DirectAdd(existingValue, 0, out _).Dispose();
}
}
tree.DirectAdd(value, 0, out _).Dispose();
_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), TreeNodeFlags.MultiValuePageRef, out _).Dispose();
}
public void MultiDelete(Slice key, Slice value)
{
State.IsModified = true;
TreeNodeHeader *node;
var page = FindPageFor(key, out node);
if (page == null || page.LastMatch != 0)
{
return; //nothing to delete - key not found
}
page = ModifyPage(page);
var item = page.GetNode(page.LastSearchPosition);
if (item->Flags == TreeNodeFlags.MultiValuePageRef) //multi-value tree exists
{
var tree = OpenMultiValueTree(key, item);
tree.Delete(value);
// 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.NumberOfEntries != 0)
{
return;
}
_tx.TryRemoveMultiValueTree(this, key);
if (_newPageAllocator != null)
{
if (IsIndexTree == false)
{
ThrowAttemptToFreePageToNewPageAllocator(Name, tree.State.RootPageNumber);
}
_newPageAllocator.FreePage(tree.State.RootPageNumber);
}
else
{
if (IsIndexTree)
{
ThrowAttemptToFreeIndexPageToFreeSpaceHandling(Name, tree.State.RootPageNumber);
}
_llt.FreePage(tree.State.RootPageNumber);
}
Delete(key);
}
else // we use a nested page here
{
var nestedPage = new TreePage(DirectAccessFromHeader(item), (ushort)GetDataSize(item));
nestedPage.Search(_llt, value); // need to search the value in the nested page
if (nestedPage.LastMatch != 0) // value not found
{
return;
}
if (item->Flags == TreeNodeFlags.PageRef)
{
throw new InvalidOperationException("Multi trees don't use overflows");
}
var nestedPagePtr = DirectAccessFromHeader(item);
nestedPage = new TreePage(nestedPagePtr, (ushort)GetDataSize(item))
{
LastSearchPosition = nestedPage.LastSearchPosition
};
nestedPage.RemoveNode(nestedPage.LastSearchPosition);
if (nestedPage.NumberOfEntries == 0)
{
Delete(key);
}
}
}
public byte *Execute()
{
using (DisableFreeSpaceUsageIfSplittingRootTree())
{
TreePage rightPage = _tree.NewPage(_page.TreeFlags, 1);
if (_cursor.PageCount == 0) // we need to do a root split
{
TreePage newRootPage = _tree.NewPage(TreePageFlags.Branch, 1);
_cursor.Push(newRootPage);
_tree.State.RootPageNumber = newRootPage.PageNumber;
_tree.State.Depth++;
// now add implicit left page
newRootPage.AddPageRefNode(0, Slices.BeforeAllKeys, _page.PageNumber);
_parentPage = newRootPage;
_parentPage.LastSearchPosition++;
}
else
{
// we already popped the page, so the current one on the stack is the parent of the page
_parentPage = _tree.ModifyPage(_cursor.CurrentPage);
_cursor.Update(_cursor.Pages.First, _parentPage);
}
if (_page.IsLeaf)
{
_tree.ClearPagesCache();
}
if (_page.IsCompressed)
{
_pageDecompressed = _tree.DecompressPage(_page);
_pageDecompressed.Search(_tx, _newKey);
_page = _pageDecompressed;
}
using (_pageDecompressed)
{
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
TreePage branchOfSeparator;
byte *pos;
if (_page.IsBranch)
{
if (_page.NumberOfEntries > 2)
{
// here we steal the last entry from the current page so we maintain the implicit null left entry
TreeNodeHeader *node = _page.GetNode(_page.NumberOfEntries - 1);
Debug.Assert(node->Flags == TreeNodeFlags.PageRef);
rightPage.AddPageRefNode(0, Slices.BeforeAllKeys, node->PageNumber);
pos = AddNodeToPage(rightPage, 1);
Slice separatorKey;
using (TreeNodeHeader.ToSlicePtr(_tx.Allocator, node, out separatorKey))
{
AddSeparatorToParentPage(rightPage.PageNumber, separatorKey, out branchOfSeparator);
}
_page.RemoveNode(_page.NumberOfEntries - 1);
}
else
{
_tree.FreePage(rightPage); // return the unnecessary right page
pos = AddSeparatorToParentPage(_pageNumber, _newKey, out branchOfSeparator);
if (_cursor.CurrentPage.PageNumber != branchOfSeparator.PageNumber)
{
_cursor.Push(branchOfSeparator);
}
return(pos);
}
}
else
{
AddSeparatorToParentPage(rightPage.PageNumber, _newKey, out branchOfSeparator);
pos = AddNodeToPage(rightPage, 0);
}
_cursor.Push(rightPage);
return(pos);
}
return(SplitPageInHalf(rightPage));
}
}
}
private void MoveBranchNode(TreePage parentPage, TreePage from, TreePage to)
{
Debug.Assert(from.IsBranch);
Slice originalFromKey;
using (GetActualKey(from, from.LastSearchPositionOrLastEntry, out originalFromKey))
{
to.EnsureHasSpaceFor(_tx, originalFromKey, -1);
var fromNode = from.GetNode(from.LastSearchPosition);
long pageNum = fromNode->PageNumber;
if (to.LastSearchPosition == 0)
{
// cannot add to left implicit side, adjust by moving the left node
// to the right by one, then adding the new one as the left
TreeNodeHeader *actualKeyNode;
Slice implicitLeftKey;
using (GetActualKey(to, 0, out actualKeyNode, out implicitLeftKey))
{
var implicitLeftNode = to.GetNode(0);
var leftPageNumber = implicitLeftNode->PageNumber;
Slice implicitLeftKeyToInsert;
ByteStringContext.ExternalScope?externalScope;
if (implicitLeftNode == actualKeyNode)
{
externalScope = TreeNodeHeader.ToSlicePtr(_tx.Allocator, actualKeyNode, out implicitLeftKeyToInsert);
}
else
{
implicitLeftKeyToInsert = implicitLeftKey;
externalScope = null;
}
to.EnsureHasSpaceFor(_tx, implicitLeftKeyToInsert, -1);
to.AddPageRefNode(1, implicitLeftKeyToInsert, leftPageNumber);
externalScope?.Dispose();
to.ChangeImplicitRefPageNode(pageNum); // setup the new implicit node
}
}
else
{
to.AddPageRefNode(to.LastSearchPosition, originalFromKey, pageNum);
}
}
if (from.LastSearchPositionOrLastEntry == 0)
{
var rightPageNumber = from.GetNode(1)->PageNumber;
from.RemoveNode(0); // remove the original implicit node
from.ChangeImplicitRefPageNode(rightPageNumber); // setup the new implicit node
Debug.Assert(from.NumberOfEntries >= 2);
}
else
{
from.RemoveNode(from.LastSearchPositionOrLastEntry);
}
var pos = parentPage.LastSearchPositionOrLastEntry;
parentPage.RemoveNode(pos);
Slice newSeparatorKey;
var scope = GetActualKey(to, 0, out newSeparatorKey); // get the next smallest key it has now
try
{
var pageNumber = to.PageNumber;
if (parentPage.GetNode(0)->PageNumber == to.PageNumber)
{
pageNumber = from.PageNumber;
scope.Dispose();
scope = GetActualKey(from, 0, out newSeparatorKey);
}
AddSeparatorToParentPage(to, parentPage, pageNumber, newSeparatorKey, pos);
}
finally
{
scope.Dispose();
}
}
private void MoveLeafNode(TreePage parentPage, TreePage from, TreePage to)
{
Debug.Assert(from.IsBranch == false);
Slice originalFromKeyStart;
using (GetActualKey(from, from.LastSearchPositionOrLastEntry, out originalFromKeyStart))
{
var fromNode = from.GetNode(from.LastSearchPosition);
byte *val = @from.Base + @from.KeysOffsets[@from.LastSearchPosition] + Constants.Tree.NodeHeaderSize +
originalFromKeyStart.Size;
byte *dataPos;
var fromDataSize = fromNode->DataSize;
switch (fromNode->Flags)
{
case TreeNodeFlags.PageRef:
to.EnsureHasSpaceFor(_tx, originalFromKeyStart, -1);
dataPos = to.AddPageRefNode(to.LastSearchPosition, originalFromKeyStart, fromNode->PageNumber);
break;
case TreeNodeFlags.Data:
to.EnsureHasSpaceFor(_tx, originalFromKeyStart, fromDataSize);
dataPos = to.AddDataNode(to.LastSearchPosition, originalFromKeyStart, fromDataSize);
break;
case TreeNodeFlags.MultiValuePageRef:
to.EnsureHasSpaceFor(_tx, originalFromKeyStart, fromDataSize);
dataPos = to.AddMultiValueNode(to.LastSearchPosition, originalFromKeyStart, fromDataSize);
break;
default:
throw new NotSupportedException("Invalid node type to move: " + fromNode->Flags);
}
if (dataPos != null && fromDataSize > 0)
{
Memory.Copy(dataPos, val, fromDataSize);
}
from.RemoveNode(from.LastSearchPositionOrLastEntry);
var pos = parentPage.LastSearchPositionOrLastEntry;
parentPage.RemoveNode(pos);
Slice newSeparatorKey;
var scope = GetActualKey(to, 0, out newSeparatorKey); // get the next smallest key it has now
try
{
var pageNumber = to.PageNumber;
if (parentPage.GetNode(0)->PageNumber == to.PageNumber)
{
pageNumber = from.PageNumber;
scope.Dispose();
scope = GetActualKey(from, 0, out newSeparatorKey);
}
AddSeparatorToParentPage(to, parentPage, pageNumber, newSeparatorKey, pos);
}
finally
{
scope.Dispose();
}
}
}
public void MultiDelete(Slice key, Slice value, ushort?version = null)
{
State.IsModified = true;
TreeNodeHeader *node;
var page = FindPageFor(key, out node);
if (page == null || page.LastMatch != 0)
{
return; //nothing to delete - key not found
}
page = ModifyPage(page);
var item = page.GetNode(page.LastSearchPosition);
if (item->Flags == TreeNodeFlags.MultiValuePageRef) //multi-value tree exists
{
var tree = OpenMultiValueTree(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.NumberOfEntries != 0)
{
return;
}
_tx.TryRemoveMultiValueTree(this, key);
_llt.FreePage(tree.State.RootPageNumber);
Delete(key);
}
else // we use a nested page here
{
var nestedPage = new TreePage(TreeNodeHeader.DirectAccess(_llt, item), "multi tree", (ushort)TreeNodeHeader.GetDataSize(_llt, item));
var nestedItem = nestedPage.Search(_llt, value);
if (nestedPage.LastMatch != 0) // value not found
{
return;
}
if (item->Flags == TreeNodeFlags.PageRef)
{
throw new InvalidOperationException("Multi trees don't use overflows");
}
var nestedPagePtr = TreeNodeHeader.DirectAccess(_llt, item);
nestedPage = new TreePage(nestedPagePtr, "multi tree", (ushort)TreeNodeHeader.GetDataSize(_llt, item))
{
LastSearchPosition = nestedPage.LastSearchPosition
};
CheckConcurrency(key, value, version, nestedItem->Version, TreeActionType.Delete);
nestedPage.RemoveNode(nestedPage.LastSearchPosition);
if (nestedPage.NumberOfEntries == 0)
{
Delete(key);
}
}
}
private void MoveLeafNode(TreePage parentPage, TreePage from, TreePage to)
{
Debug.Assert(from.IsBranch == false);
var originalFromKeyStart = GetActualKey(from, from.LastSearchPositionOrLastEntry);
var fromNode = from.GetNode(from.LastSearchPosition);
byte *val = @from.Base + @from.KeysOffsets[@from.LastSearchPosition] + Constants.NodeHeaderSize + originalFromKeyStart.Size;
var nodeVersion = fromNode->Version; // every time new node is allocated the version is increased, but in this case we do not want to increase it
if (nodeVersion > 0)
{
nodeVersion -= 1;
}
byte *dataPos;
var fromDataSize = fromNode->DataSize;
switch (fromNode->Flags)
{
case TreeNodeFlags.PageRef:
to.EnsureHasSpaceFor(_tx, originalFromKeyStart, -1);
dataPos = to.AddPageRefNode(to.LastSearchPosition, originalFromKeyStart, fromNode->PageNumber);
break;
case TreeNodeFlags.Data:
to.EnsureHasSpaceFor(_tx, originalFromKeyStart, fromDataSize);
dataPos = to.AddDataNode(to.LastSearchPosition, originalFromKeyStart, fromDataSize, nodeVersion);
break;
case TreeNodeFlags.MultiValuePageRef:
to.EnsureHasSpaceFor(_tx, originalFromKeyStart, fromDataSize);
dataPos = to.AddMultiValueNode(to.LastSearchPosition, originalFromKeyStart, fromDataSize, nodeVersion);
break;
default:
throw new NotSupportedException("Invalid node type to move: " + fromNode->Flags);
}
if (dataPos != null && fromDataSize > 0)
{
Memory.Copy(dataPos, val, fromDataSize);
}
from.RemoveNode(from.LastSearchPositionOrLastEntry);
var pos = parentPage.LastSearchPositionOrLastEntry;
parentPage.RemoveNode(pos);
var newSeparatorKey = GetActualKey(to, 0); // get the next smallest key it has now
var pageNumber = to.PageNumber;
if (parentPage.GetNode(0)->PageNumber == to.PageNumber)
{
pageNumber = from.PageNumber;
newSeparatorKey = GetActualKey(from, 0);
}
AddSeparatorToParentPage(to, parentPage, pageNumber, newSeparatorKey, pos);
}