/// <summary>
/// Internal method that is used when splitting pages
/// No need to do any work here, we are always adding at the end
/// </summary>
internal void CopyNodeDataToEndOfPage(TreeNodeHeader *other, Slice key)
{
var index = NumberOfEntries;
Debug.Assert(HasSpaceFor(TreeSizeOf.NodeEntryWithAnotherKey(other, key) + Constants.Tree.NodeOffsetSize));
var nodeSize = TreeSizeOf.NodeEntryWithAnotherKey(other, key);
Debug.Assert(IsBranch == false || index != 0 || key.Size == 0);// branch page's first item must be the implicit ref
var newNode = AllocateNewNode(index, nodeSize);
Debug.Assert(key.Size <= ushort.MaxValue);
newNode->KeySize = (ushort)key.Size;
newNode->Flags = other->Flags;
if (key.Options == SliceOptions.Key && key.Size > 0)
{
key.CopyTo((byte *)newNode + Constants.Tree.NodeHeaderSize);
}
if (IsBranch || other->Flags == (TreeNodeFlags.PageRef))
{
newNode->PageNumber = other->PageNumber;
newNode->Flags = TreeNodeFlags.PageRef;
return;
}
newNode->DataSize = other->DataSize;
Memory.Copy((byte *)newNode + Constants.Tree.NodeHeaderSize + key.Size,
(byte *)other + Constants.Tree.NodeHeaderSize + other->KeySize,
other->DataSize);
}
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);
}
