private ActualKeyScope GetActualKey(TreePage page, int pos, out TreeNodeHeader *node, out Slice key)
{
DecompressedLeafPage decompressedLeafPage = null;
node = page.GetNode(pos);
var scope = TreeNodeHeader.ToSlicePtr(_tx.Allocator, node, out key);
while (key.Size == 0)
{
Debug.Assert(page.IsBranch);
page = _tree.GetReadOnlyTreePage(node->PageNumber);
if (page.IsCompressed == false)
{
node = page.GetNode(0);
}
else
{
decompressedLeafPage?.Dispose();
decompressedLeafPage = _tree.DecompressPage(page, skipCache: true);
if (decompressedLeafPage.NumberOfEntries > 0)
{
node = decompressedLeafPage.GetNode(0);
}
else
{
// we have empty page after decompression (each compressed entry has a corresponding CompressionTombstone)
// we can safely use the node key of first tombstone (they have proper order)
node = page.GetNode(0);
}
}
scope.Dispose();
scope = TreeNodeHeader.ToSlicePtr(_tx.Allocator, node, out key);
}
return(new ActualKeyScope
{
DecompressedLeafPage = decompressedLeafPage,
ExternalScope = scope
});
}
private void HandleTombstone(DecompressedLeafPage decompressedPage, Slice nodeKey, DecompressionUsage usage)
{
decompressedPage.Search(_llt, nodeKey);
if (decompressedPage.LastMatch != 0)
{
return;
}
var node = decompressedPage.GetNode(decompressedPage.LastSearchPosition);
if (usage == DecompressionUsage.Write)
{
State.NumberOfEntries--;
if (node->Flags == TreeNodeFlags.PageRef)
{
var overflowPage = GetReadOnlyTreePage(node->PageNumber);
FreePage(overflowPage);
}
}
decompressedPage.RemoveNode(decompressedPage.LastSearchPosition);
}
private ActualKeyScope GetActualKey(TreePage page, int pos, out TreeNodeHeader *node, out Slice key)
{
DecompressedLeafPage decompressedLeafPage = null;
node = page.GetNode(pos);
var scope = TreeNodeHeader.ToSlicePtr(_tx.Allocator, node, out key);
while (key.Size == 0)
{
Debug.Assert(page.IsBranch);
page = _tree.GetReadOnlyTreePage(node->PageNumber);
if (page.IsCompressed == false)
{
node = page.GetNode(0);
}
else
{
decompressedLeafPage?.Dispose();
decompressedLeafPage = _tree.DecompressPage(page, DecompressionUsage.Read, skipCache: true);
if (decompressedLeafPage.NumberOfEntries > 0)
{
if (page.NumberOfEntries == 0)
{
node = decompressedLeafPage.GetNode(0);
}
else
{
// we want to find the smallest key in compressed page
// it can be inside compressed part or not compressed one
// in particular, it can be the key of compression tombstone node that we don't see after decompression
// so we need to take first keys from decompressed and compressed page and compare them
var decompressedNode = decompressedLeafPage.GetNode(0);
var compressedNode = page.GetNode(0);
using (TreeNodeHeader.ToSlicePtr(_tx.Allocator, decompressedNode, out var firstDecompressedKey))
using (TreeNodeHeader.ToSlicePtr(_tx.Allocator, compressedNode, out var firstCompressedKey))
{
node = SliceComparer.CompareInline(firstDecompressedKey, firstCompressedKey) > 0 ? compressedNode : decompressedNode;
}
}
}
else
{
// we have empty page after decompression (each compressed entry has a corresponding CompressionTombstone)
// we can safely use the node key of first tombstone (they have proper order)
node = page.GetNode(0);
}
}
scope.Dispose();
scope = TreeNodeHeader.ToSlicePtr(_tx.Allocator, node, out key);
}
return(new ActualKeyScope
{
DecompressedLeafPage = decompressedLeafPage,
ExternalScope = scope
});
}
