private void RecompressPageIfNeeded(bool wasModified)
{
if (_pageDecompressed == null)
{
return;
}
_pageDecompressed.CopyToOriginal(_tx, defragRequired: false, wasModified: wasModified);
_tree.DecompressionsCache.Invalidate(_pageDecompressed.PageNumber, DecompressionUsage.Read);
_page = _pageDecompressed.Original;
}
private byte *SplitPageInHalf(TreePage rightPage)
{
bool toRight;
var currentIndex = _page.LastSearchPosition;
var splitIndex = _page.NumberOfEntries / 2;
if (currentIndex <= splitIndex)
{
toRight = false;
}
else
{
toRight = true;
var leftPageEntryCount = splitIndex;
var rightPageEntryCount = _page.NumberOfEntries - leftPageEntryCount + 1;
if (rightPageEntryCount > leftPageEntryCount)
{
splitIndex++;
Debug.Assert(splitIndex < _page.NumberOfEntries);
}
}
if (_page.IsLeaf)
{
splitIndex = AdjustSplitPosition(currentIndex, splitIndex, ref toRight);
}
Slice currentKey;
using (_page.GetNodeKey(_tx, splitIndex, out currentKey))
{
Slice seperatorKey;
if (toRight && splitIndex == currentIndex)
{
seperatorKey = SliceComparer.Compare(currentKey, _newKey) < 0 ? currentKey : _newKey;
}
else
{
seperatorKey = currentKey;
}
var addedAsImplicitRef = false;
var parentOfPage = _cursor.CurrentPage;
TreePage parentOfRight;
DecompressedLeafPage rightDecompressed = null;
if (_pageDecompressed != null)
{
// splitting the decompressed page, let's allocate the page of the same size to ensure enough space
rightDecompressed = _tx.Environment.DecompressionBuffers.GetPage(_tx, _pageDecompressed.PageSize, DecompressionUsage.Write, rightPage);
rightPage = rightDecompressed;
}
using (rightDecompressed)
{
AddSeparatorToParentPage(rightPage.PageNumber, seperatorKey, out parentOfRight);
if (_page.IsBranch && toRight && SliceComparer.EqualsInline(seperatorKey, _newKey))
{
// _newKey needs to be inserted as first key (BeforeAllKeys) to the right page, so we need to add it before we move entries from the current page
AddNodeToPage(rightPage, 0, Slices.BeforeAllKeys);
addedAsImplicitRef = true;
}
// move the actual entries from page to right page
ushort nKeys = _page.NumberOfEntries;
for (int i = splitIndex; i < nKeys; i++)
{
TreeNodeHeader *node = _page.GetNode(i);
if (_page.IsBranch && rightPage.NumberOfEntries == 0)
{
rightPage.CopyNodeDataToEndOfPage(node, Slices.BeforeAllKeys);
}
else
{
Slice instance;
using (TreeNodeHeader.ToSlicePtr(_tx.Allocator, node, out instance))
{
rightPage.CopyNodeDataToEndOfPage(node, instance);
}
}
}
if (rightDecompressed != null)
{
rightDecompressed.CopyToOriginal(_tx, defragRequired: false, wasModified: true);
rightPage = rightDecompressed.Original;
}
}
_page.Truncate(_tx, splitIndex);
RecompressPageIfNeeded(wasModified: true);
byte *pos;
if (addedAsImplicitRef == false)
{
try
{
if (toRight && _cursor.CurrentPage.PageNumber != parentOfRight.PageNumber)
{
// modify the cursor if we are going to insert to the right page
_cursor.Pop();
_cursor.Push(parentOfRight);
}
// actually insert the new key
pos = InsertNewKey(toRight ? rightPage : _page);
}
catch (InvalidOperationException e)
{
if (
e.Message.StartsWith("The page is full and cannot add an entry", StringComparison.Ordinal) ==
false)
{
throw;
}
throw new InvalidOperationException(
GatherDetailedDebugInfo(rightPage, currentKey, seperatorKey, currentIndex, splitIndex,
toRight), e);
}
}
else
{
pos = null;
_cursor.Push(rightPage);
}
if (_page.IsBranch)
// remove a branch that has only one entry, the page ref needs to be added to the parent of the current page
{
Debug.Assert(_page.NumberOfEntries > 0);
Debug.Assert(rightPage.NumberOfEntries > 0);
if (_page.NumberOfEntries == 1)
{
RemoveBranchWithOneEntry(_page, parentOfPage);
}
if (rightPage.NumberOfEntries == 1)
{
RemoveBranchWithOneEntry(rightPage, parentOfRight);
}
}
return(pos);
}
}