예제 #1
0
        private byte *AddSeparatorToParentPage(long pageNumber, MemorySlice seperatorKey, bool toRight, out Page parent)
        {
            var pos = _parentPage.NodePositionFor(seperatorKey); // select the appropriate place for this

            var separatorKeyToInsert = _parentPage.PrepareKeyToInsert(seperatorKey, pos);

            if (_parentPage.HasSpaceFor(_tx, SizeOf.BranchEntry(separatorKeyToInsert) + Constants.NodeOffsetSize + SizeOf.NewPrefix(separatorKeyToInsert)) == false)
            {
                var pageSplitter = new PageSplitter(_tx, _tree, seperatorKey, -1, pageNumber, NodeFlags.PageRef,
                                                    0, _cursor, _treeState);

                var posToInsert = pageSplitter.Execute();

                if (toRight == false && _cursor.CurrentPage.PageNumber != _parentPage.PageNumber)
                {
                    // _newKey being added to _page wasn't meant to be inserted to a newly created right page
                    // however the above page split has modified the cursor that its first page is a parent page for the right page containing separator key
                    // we need to ensure that the current _parentPage is first at the cursor

                    parent = _cursor.Pop();
                    _cursor.Push(_parentPage);
                }
                else
                {
                    parent = _parentPage;
                }

                return(posToInsert);
            }

            parent = _parentPage;

            return(_parentPage.AddPageRefNode(pos, separatorKeyToInsert, pageNumber));
        }
예제 #2
0
        private byte *SplitPageInHalf(Page rightPage)
        {
            int  currentIndex = _page.LastSearchPosition;
            bool newPosition  = true;
            int  splitIndex   = _page.NumberOfEntries / 2;

            if (currentIndex < splitIndex)
            {
                newPosition = false;
            }

            if (_page.IsLeaf)
            {
                splitIndex = AdjustSplitPosition(currentIndex, splitIndex, ref newPosition);
            }

            var currentKey = _page.GetNodeKey(splitIndex);

            // here the current key is the separator key and can go either way, so
            // use newPosition to decide if it stays on the left node or moves to the right
            MemorySlice seperatorKey;

            if (currentIndex == splitIndex && newPosition)
            {
                seperatorKey = currentKey.Compare(_newKey) < 0 ? currentKey : _newKey;
            }
            else
            {
                seperatorKey = currentKey;
            }

            AddSeparatorToParentPage(rightPage.PageNumber, seperatorKey);

            MemorySlice instance = _page.CreateNewEmptyKey();
            // move the actual entries from page to right page
            ushort nKeys = _page.NumberOfEntries;

            for (int i = splitIndex; i < nKeys; i++)
            {
                NodeHeader *node = _page.GetNode(i);
                if (_page.IsBranch && rightPage.NumberOfEntries == 0)
                {
                    rightPage.CopyNodeDataToEndOfPage(node, _tree.KeysPrefixing ? (MemorySlice)PrefixedSlice.BeforeAllKeys : Slice.BeforeAllKeys);
                }
                else
                {
                    _page.SetNodeKey(node, ref instance);
                    var key = rightPage.PrepareKeyToInsert(instance, rightPage.NumberOfEntries);
                    rightPage.CopyNodeDataToEndOfPage(node, key);
                }
            }
            _page.Truncate(_tx, splitIndex);

            // actually insert the new key
            return((currentIndex > splitIndex || newPosition && currentIndex == splitIndex)
                ? InsertNewKey(rightPage)
                : InsertNewKey(_page));
        }
예제 #3
0
        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;
                MemoryUtils.Copy(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      = KeysPrefixing ? (ushort)(newSize - Constants.PrefixInfoSectionSize) : newSize,
                    Flags      = KeysPrefixing ? PageFlags.Leaf | PageFlags.KeysPrefixed : PageFlags.Leaf,
                    PageNumber = -1L                     // mark as invalid page number
                };

                newNestedPage.ClearPrefixInfo();

                MemorySlice nodeKey = nestedPage.CreateNewEmptyKey();
                for (int i = 0; i < nestedPage.NumberOfEntries; i++)
                {
                    var nodeHeader = nestedPage.GetNode(i);
                    nestedPage.SetNodeKey(nodeHeader, ref nodeKey);
                    nodeKey = newNestedPage.PrepareKeyToInsert(nodeKey, i);
                    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, newNestedPage.PrepareKeyToInsert(value, newNestedPage.LastSearchPosition), 0, 0);
            }
        }
예제 #4
0
        private void AddSeparatorToParentPage(Page parentPage, long pageNumber, MemorySlice seperatorKey, int separatorKeyPosition)
        {
            var separatorKeyToInsert = parentPage.PrepareKeyToInsert(seperatorKey, separatorKeyPosition);

            if (parentPage.HasSpaceFor(_tx, SizeOf.BranchEntry(separatorKeyToInsert) + Constants.NodeOffsetSize + SizeOf.NewPrefix(separatorKeyToInsert)) == false)
            {
                var pageSplitter = new PageSplitter(_tx, _tree, seperatorKey, -1, pageNumber, NodeFlags.PageRef,
                                                    0, _cursor, _tree.State);
                pageSplitter.Execute();
            }
            else
            {
                parentPage.AddPageRefNode(separatorKeyPosition, separatorKeyToInsert, pageNumber);
            }
        }
예제 #5
0
        private byte *AddSeparatorToParentPage(long pageNumber, MemorySlice seperatorKey)
        {
            var pos = _parentPage.NodePositionFor(seperatorKey);             // select the appropriate place for this

            var separatorKeyToInsert = _parentPage.PrepareKeyToInsert(seperatorKey, pos);

            if (_parentPage.HasSpaceFor(_tx, SizeOf.BranchEntry(separatorKeyToInsert) + Constants.NodeOffsetSize + SizeOf.NewPrefix(separatorKeyToInsert)) == false)
            {
                var pageSplitter = new PageSplitter(_tx, _tree, seperatorKey, -1, pageNumber, NodeFlags.PageRef,
                                                    0, _cursor, _treeState);
                return(pageSplitter.Execute());
            }

            return(_parentPage.AddPageRefNode(pos, separatorKeyToInsert, pageNumber));
        }
예제 #6
0
파일: PageSplitter.cs 프로젝트: mow/ravendb
        private byte *AddNodeToPage(Page page, int index, MemorySlice alreadyPreparedNewKey = null)
        {
            var newKeyToInsert = alreadyPreparedNewKey ?? page.PrepareKeyToInsert(_newKey, index);

            switch (_nodeType)
            {
            case NodeFlags.PageRef:
                return(page.AddPageRefNode(index, newKeyToInsert, _pageNumber));

            case NodeFlags.Data:
                return(page.AddDataNode(index, newKeyToInsert, _len, _nodeVersion));

            case NodeFlags.MultiValuePageRef:
                return(page.AddMultiValueNode(index, newKeyToInsert, _len, _nodeVersion));

            default:
                throw new NotSupportedException("Unknown node type");
            }
        }
예제 #7
0
파일: PageSplitter.cs 프로젝트: mow/ravendb
        private byte *InsertNewKey(Page p)
        {
            int pos = p.NodePositionFor(_newKey);

            var newKeyToInsert = p.PrepareKeyToInsert(_newKey, pos);

            if (p.HasSpaceFor(_tx, p.GetRequiredSpace(newKeyToInsert, _len)) == false)
            {
                _cursor.Push(p);

                var pageSplitter = new PageSplitter(_tx, _tree, _newKey, _len, _pageNumber, _nodeType, _nodeVersion, _cursor, _treeState);

                return(pageSplitter.Execute());
            }

            byte *dataPos = AddNodeToPage(p, pos, newKeyToInsert);

            _cursor.Push(p);
            return(dataPos);
        }
예제 #8
0
        public void MultiAdd(Slice key, Slice value, ushort?version = null)
        {
            if (value == null)
            {
                throw new ArgumentNullException("value");
            }
            int maxNodeSize = AbstractPager.NodeMaxSize;

            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;
            NodeHeader *  node;
            var           page = FindPageFor(key, out node, 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 = OpenMultiValueTree(_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 = page.GetNodeKey(item);
                if (tmpKey.Compare(value) == 0)
                {
                    return;                     // already there, turning into a no-op
                }
                nestedPage.RemoveNode(nestedPage.LastSearchPosition);
            }

            var valueToInsert = nestedPage.PrepareKeyToInsert(value, nestedPage.LastSearchPosition);

            if (nestedPage.HasSpaceFor(_tx, valueToInsert, 0))
            {
                // we are now working on top of the modified root page, we can just modify the memory directly
                nestedPage.AddDataNode(nestedPage.LastSearchPosition, valueToInsert, 0, previousNodeRevision);
                return;
            }

            int pageSize        = nestedPage.CalcSizeUsed() + Constants.PageHeaderSize;
            var newRequiredSize = pageSize + nestedPage.GetRequiredSpace(valueToInsert, 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);

                var currentDataSize = NodeHeader.GetDataSize(_tx, item);
                ExpandMultiTreeNestedPageSize(_tx, key, value, nestedPagePtr, actualPageSize, currentDataSize);

                return;
            }
            // we now have to convert this into a tree instance, instead of just a nested page
            var tree = Create(_tx, KeysPrefixing, 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);
        }
예제 #9
0
        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);
        }
예제 #10
0
        private void MoveBranchNode(Page parentPage, Page from, Page to)
        {
            Debug.Assert(from.IsBranch);

	        var originalFromKey = to.PrepareKeyToInsert(GetActualKey(from, from.LastSearchPositionOrLastEntry), to.LastSearchPosition);

            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

	            NodeHeader* actualKeyNode;
                var implicitLeftKey = GetActualKey(to, 0, out actualKeyNode);
	            var implicitLeftNode = to.GetNode(0);
				var leftPageNumber = implicitLeftNode->PageNumber;

	            MemorySlice implicitLeftKeyToInsert;

	            if (implicitLeftNode == actualKeyNode)
	            {
					// no need to create a prefix, just use the existing prefixed key from the node
					// this also prevents from creating a prefix which is the full key given in 'implicitLeftKey'

		            if (_tree.KeysPrefixing)
			            implicitLeftKeyToInsert = new PrefixedSlice(actualKeyNode);
		            else
			            implicitLeftKeyToInsert = new Slice(actualKeyNode);
	            }
				else
					implicitLeftKeyToInsert = to.PrepareKeyToInsert(implicitLeftKey, 1);
	            
				to.EnsureHasSpaceFor(_tx, implicitLeftKeyToInsert, -1);
				to.AddPageRefNode(1, implicitLeftKeyToInsert, leftPageNumber);

				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);
            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(parentPage, pageNumber, newSeparatorKey, pos);
        }
예제 #11
0
        private void MoveLeafNode(Page parentPage, Page from, Page 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;

	        var prefixedOriginalFromKey = to.PrepareKeyToInsert(originalFromKeyStart, to.LastSearchPosition);

	        byte* dataPos;
	        var fromDataSize = fromNode->DataSize;
	        switch (fromNode->Flags)
	        {
				case NodeFlags.PageRef:
					to.EnsureHasSpaceFor(_tx, prefixedOriginalFromKey, -1);
					dataPos = to.AddPageRefNode(to.LastSearchPosition, prefixedOriginalFromKey, fromNode->PageNumber);
					break;
				case NodeFlags.Data:
					to.EnsureHasSpaceFor(_tx, prefixedOriginalFromKey, fromDataSize);
					dataPos = to.AddDataNode(to.LastSearchPosition, prefixedOriginalFromKey, fromDataSize, nodeVersion);
					break;
				case NodeFlags.MultiValuePageRef:
					to.EnsureHasSpaceFor(_tx, prefixedOriginalFromKey, fromDataSize);
					dataPos = to.AddMultiValueNode(to.LastSearchPosition, prefixedOriginalFromKey, 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(parentPage, pageNumber, newSeparatorKey, pos);
        }
예제 #12
0
        private byte* AddNodeToPage(Page page, int index, MemorySlice alreadyPreparedNewKey = null)
        {
	        var newKeyToInsert = alreadyPreparedNewKey ?? page.PrepareKeyToInsert(_newKey, index);

            switch (_nodeType)
            {
                case NodeFlags.PageRef:
					return page.AddPageRefNode(index, newKeyToInsert, _pageNumber);
                case NodeFlags.Data:
					return page.AddDataNode(index, newKeyToInsert, _len, _nodeVersion);
                case NodeFlags.MultiValuePageRef:
					return page.AddMultiValueNode(index, newKeyToInsert, _len, _nodeVersion);
                default:
                    throw new NotSupportedException("Unknown node type");
            }
        }
예제 #13
0
        private byte* SplitPageInHalf(Page rightPage)
        {
            int currentIndex = _page.LastSearchPosition;
            bool newPosition = true;
            int splitIndex = _page.NumberOfEntries/2;
            if (currentIndex < splitIndex)
                newPosition = false;

            if (_page.IsLeaf)
            {
                splitIndex = AdjustSplitPosition(currentIndex, splitIndex, ref newPosition);
            }

	        var currentKey = _page.GetNodeKey(splitIndex);

            // here the current key is the separator key and can go either way, so 
            // use newPosition to decide if it stays on the left node or moves to the right
            MemorySlice seperatorKey;
            if (currentIndex == splitIndex && newPosition)
            {
                seperatorKey = currentKey.Compare(_newKey) < 0 ? currentKey : _newKey;
            }
            else
            {
                seperatorKey = currentKey;
            }

            AddSeparatorToParentPage(rightPage.PageNumber, seperatorKey);

	        MemorySlice instance = _page.CreateNewEmptyKey();
            // move the actual entries from page to right page
            ushort nKeys = _page.NumberOfEntries;
            for (int i = splitIndex; i < nKeys; i++)
            {
                NodeHeader* node = _page.GetNode(i);
                if (_page.IsBranch && rightPage.NumberOfEntries == 0)
                {
                    rightPage.CopyNodeDataToEndOfPage(node, _tree.KeysPrefixing ? (MemorySlice) PrefixedSlice.BeforeAllKeys : Slice.BeforeAllKeys);
                }
                else
                {
	                _page.SetNodeKey(node, ref instance);
	                var key = rightPage.PrepareKeyToInsert(instance, rightPage.NumberOfEntries);
					rightPage.CopyNodeDataToEndOfPage(node, key);
                }
            }
            _page.Truncate(_tx, splitIndex);

            // actually insert the new key
            return (currentIndex > splitIndex || newPosition && currentIndex == splitIndex)
                ? InsertNewKey(rightPage)
                : InsertNewKey(_page);
        }
예제 #14
0
        private byte* SplitPageInHalf(Page 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);
				}
			}

			PrefixNode[] prefixes = null;

			if (_tree.KeysPrefixing && _page.HasPrefixes)
			{
				prefixes = _page.GetPrefixes();
			}

			if (_page.IsLeaf || prefixes != null)
			{
				splitIndex = AdjustSplitPosition(currentIndex, splitIndex, prefixes, ref toRight);
			}

			var currentKey = _page.GetNodeKey(splitIndex);
			MemorySlice seperatorKey;

			if (toRight && splitIndex == currentIndex)
			{
				seperatorKey = currentKey.Compare(_newKey) < 0 ? currentKey : _newKey;
			}
			else
			{
				seperatorKey = currentKey;
			}

            AddSeparatorToParentPage(rightPage.PageNumber, seperatorKey);

	        MemorySlice instance = _page.CreateNewEmptyKey();

	        if (prefixes != null)
	        {
				for (int i = 0; i < prefixes.Length; i++)
				{
					var prefix = prefixes[i];

					rightPage.WritePrefix(new Slice(prefix.ValuePtr, prefix.PrefixLength), i);
				}
	        }

	        bool addedAsImplicitRef = false;

			if (_page.IsBranch && toRight && 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, _tree.KeysPrefixing ? (MemorySlice)PrefixedSlice.BeforeAllKeys : Slice.BeforeAllKeys);
				addedAsImplicitRef = true;
			}

	        // move the actual entries from page to right page
            ushort nKeys = _page.NumberOfEntries;
            for (int i = splitIndex; i < nKeys; i++)
            {
                NodeHeader* node = _page.GetNode(i);
                if (_page.IsBranch && rightPage.NumberOfEntries == 0)
                {
                    rightPage.CopyNodeDataToEndOfPage(node, _tree.KeysPrefixing ? (MemorySlice) PrefixedSlice.BeforeAllKeys : Slice.BeforeAllKeys);
                }
                else
                {
	                _page.SetNodeKey(node, ref instance);
	                var key = rightPage.PrepareKeyToInsert(instance, rightPage.NumberOfEntries);

					rightPage.CopyNodeDataToEndOfPage(node, key);
                }
            }

            _page.Truncate(_tx, splitIndex);

			byte* pos;

	        if (addedAsImplicitRef == false)
	        {
				try
				{
					// actually insert the new key
					pos = toRight ? InsertNewKey(rightPage) : InsertNewKey(_page);
				}
				catch (InvalidOperationException e)
				{
					if (e.Message.StartsWith("The page is full and cannot add an entry") == 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, _cursor.ParentPage);

				if (rightPage.NumberOfEntries == 1)
					RemoveBranchWithOneEntry(rightPage, _cursor.ParentPage);
			}

			return pos;
        }
예제 #15
0
        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 = KeysPrefixing ? (ushort) (newSize - Constants.PrefixInfoSectionSize) : newSize,
                    Flags = KeysPrefixing ? PageFlags.Leaf | PageFlags.KeysPrefixed : PageFlags.Leaf,
                    PageNumber = -1L // mark as invalid page number
                };

                newNestedPage.ClearPrefixInfo();

                MemorySlice nodeKey = nestedPage.CreateNewEmptyKey();
                for (int i = 0; i < nestedPage.NumberOfEntries; i++)
                {
                    var nodeHeader = nestedPage.GetNode(i);
                    nestedPage.SetNodeKey(nodeHeader, ref nodeKey);
                    nodeKey = newNestedPage.PrepareKeyToInsert(nodeKey, i);
                    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, newNestedPage.PrepareKeyToInsert(value, newNestedPage.LastSearchPosition), 0, 0);
            }
        }
예제 #16
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;
            NodeHeader* node;
            var page = FindPageFor(key, out node, 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 = OpenMultiValueTree(_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 = page.GetNodeKey(item);
                if (tmpKey.Compare(value) == 0)
                    return; // already there, turning into a no-op
                nestedPage.RemoveNode(nestedPage.LastSearchPosition);
            }

            var valueToInsert = nestedPage.PrepareKeyToInsert(value, nestedPage.LastSearchPosition);

            if (nestedPage.HasSpaceFor(_tx, valueToInsert, 0))
            {
                // we are now working on top of the modified root page, we can just modify the memory directly
                nestedPage.AddDataNode(nestedPage.LastSearchPosition, valueToInsert, 0, previousNodeRevision);
                return;
            }

            int pageSize = nestedPage.CalcSizeUsed() + Constants.PageHeaderSize;
            var newRequiredSize = pageSize + nestedPage.GetRequiredSpace(valueToInsert, 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, KeysPrefixing, 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);
        }
예제 #17
0
        private byte* SplitPageInHalf(Page rightPage)
        {
            int currentIndex = _page.LastSearchPosition;
            bool newPosition = true;
            int splitIndex = _page.NumberOfEntries/2;
            if (currentIndex < splitIndex)
                newPosition = false;

	        PrefixNode[] prefixes = null;

	        if (_tree.KeysPrefixing && _page.HasPrefixes)
	        {
		        prefixes = _page.GetPrefixes();
	        }

	        if (_page.IsLeaf || prefixes != null)
            {
                splitIndex = AdjustSplitPosition(currentIndex, splitIndex, prefixes, ref newPosition);
            }

	        var currentKey = _page.GetNodeKey(splitIndex);

            // here the current key is the separator key and can go either way, so 
            // use newPosition to decide if it stays on the left node or moves to the right
            MemorySlice seperatorKey;
            if (currentIndex == splitIndex && newPosition)
            {
                seperatorKey = currentKey.Compare(_newKey) < 0 ? currentKey : _newKey;
            }
            else
            {
                seperatorKey = currentKey;
            }

            AddSeparatorToParentPage(rightPage.PageNumber, seperatorKey);

	        MemorySlice instance = _page.CreateNewEmptyKey();

	        if (prefixes != null)
	        {
				for (int i = 0; i < prefixes.Length; i++)
				{
					var prefix = prefixes[i];

					rightPage.WritePrefix(new Slice(prefix.ValuePtr, prefix.PrefixLength), i);
				}
	        }

	        // move the actual entries from page to right page
            ushort nKeys = _page.NumberOfEntries;
            for (int i = splitIndex; i < nKeys; i++)
            {
                NodeHeader* node = _page.GetNode(i);
                if (_page.IsBranch && rightPage.NumberOfEntries == 0)
                {
                    rightPage.CopyNodeDataToEndOfPage(node, _tree.KeysPrefixing ? (MemorySlice) PrefixedSlice.BeforeAllKeys : Slice.BeforeAllKeys);
                }
                else
                {
	                _page.SetNodeKey(node, ref instance);
	                var key = rightPage.PrepareKeyToInsert(instance, rightPage.NumberOfEntries);

					rightPage.CopyNodeDataToEndOfPage(node, key);
                }
            }
            _page.Truncate(_tx, splitIndex);

            // actually insert the new key
			try
			{
				return (currentIndex > splitIndex || newPosition && currentIndex == splitIndex)
					? InsertNewKey(rightPage)
					: InsertNewKey(_page);
			}
			catch (InvalidOperationException e)
			{
				if (e.Message.StartsWith("The page is full and cannot add an entry"))
				{
					var debugInfo = new StringBuilder();

					debugInfo.AppendFormat("\r\n_tree.Name: {0}\r\n", _tree.Name);
					debugInfo.AppendFormat("_newKey: {0}, _len: {1}, needed space: {2}\r\n", _newKey, _len, _page.GetRequiredSpace(_newKey, _len));
					debugInfo.AppendFormat("currentKey: {0}, seperatorKey: {1}\r\n", currentKey, seperatorKey);
					debugInfo.AppendFormat("currentIndex: {0}\r\n", currentIndex);
					debugInfo.AppendFormat("splitIndex: {0}\r\n", splitIndex);
					debugInfo.AppendFormat("newPosition: {0}\r\n", newPosition);

					debugInfo.AppendFormat("_page info: flags - {0}, # of entries {1}, size left: {2}, calculated size left: {3}\r\n", _page.Flags, _page.NumberOfEntries, _page.SizeLeft, _page.CalcSizeLeft());

					for (int i = 0; i < _page.NumberOfEntries; i++)
					{
						var node = _page.GetNode(i);
						var key = _page.GetNodeKey(node);
						debugInfo.AppendFormat("{0} - {2} {1}\r\n", key,
							node->DataSize, node->Flags == NodeFlags.Data ? "Size" : "Page");
					}

					debugInfo.AppendFormat("rightPage info: flags - {0}, # of entries {1}, size left: {2}, calculated size left: {3}\r\n", rightPage.Flags, rightPage.NumberOfEntries, rightPage.SizeLeft, rightPage.CalcSizeLeft());

					for (int i = 0; i < rightPage.NumberOfEntries; i++)
					{
						var node = rightPage.GetNode(i);
						var key = rightPage.GetNodeKey(node);
						debugInfo.AppendFormat("{0} - {2} {1}\r\n", key,
							node->DataSize, node->Flags == NodeFlags.Data ? "Size" : "Page");
					}

					throw new InvalidOperationException(debugInfo.ToString(), e);
				}

				throw;
			}

        }
예제 #18
0
		private void AddSeparatorToParentPage(Page parentPage, long pageNumber, MemorySlice seperatorKey, int separatorKeyPosition)
		{
			var separatorKeyToInsert = parentPage.PrepareKeyToInsert(seperatorKey, separatorKeyPosition);

			if (parentPage.HasSpaceFor(_tx, SizeOf.BranchEntry(separatorKeyToInsert) + Constants.NodeOffsetSize + SizeOf.NewPrefix(separatorKeyToInsert)) == false)
			{
				var pageSplitter = new PageSplitter(_tx, _tree, seperatorKey, -1, pageNumber, NodeFlags.PageRef,
					0, _cursor, _tree.State);
				pageSplitter.Execute();
			}
			else
			{
				parentPage.AddPageRefNode(separatorKeyPosition, separatorKeyToInsert, pageNumber);
			}
		}
예제 #19
0
        private byte* InsertNewKey(Page p)
        {
            int pos = p.NodePositionFor(_newKey);

			var newKeyToInsert = p.PrepareKeyToInsert(_newKey, pos);

			if (p.HasSpaceFor(_tx, p.GetRequiredSpace(newKeyToInsert, _len)) == false)
			{
				_cursor.Push(p);

				var pageSplitter = new PageSplitter(_tx, _tree, _newKey, _len, _pageNumber, _nodeType, _nodeVersion, _cursor, _treeState);

				return pageSplitter.Execute();
			}

            byte* dataPos = AddNodeToPage(p, pos, newKeyToInsert);
            _cursor.Push(p);
            return dataPos;
        }
예제 #20
0
        private void MoveLeafNode(Page parentPage, Page from, Page 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;
            }

            var prefixedOriginalFromKey = to.PrepareKeyToInsert(originalFromKeyStart, to.LastSearchPosition);

            byte *dataPos;
            var   fromDataSize = fromNode->DataSize;

            switch (fromNode->Flags)
            {
            case NodeFlags.PageRef:
                to.EnsureHasSpaceFor(_tx, prefixedOriginalFromKey, -1);
                dataPos = to.AddPageRefNode(to.LastSearchPosition, prefixedOriginalFromKey, fromNode->PageNumber);
                break;

            case NodeFlags.Data:
                to.EnsureHasSpaceFor(_tx, prefixedOriginalFromKey, fromDataSize);
                dataPos = to.AddDataNode(to.LastSearchPosition, prefixedOriginalFromKey, fromDataSize, nodeVersion);
                break;

            case NodeFlags.MultiValuePageRef:
                to.EnsureHasSpaceFor(_tx, prefixedOriginalFromKey, fromDataSize);
                dataPos = to.AddMultiValueNode(to.LastSearchPosition, prefixedOriginalFromKey, 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(parentPage, pageNumber, newSeparatorKey, pos);
        }
예제 #21
0
파일: PageSplitter.cs 프로젝트: mow/ravendb
        private byte *SplitPageInHalf(Page 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);
                }
            }

            PrefixNode[] prefixes = null;

            if (_tree.KeysPrefixing && _page.HasPrefixes)
            {
                prefixes = _page.GetPrefixes();
            }

            if (_page.IsLeaf || prefixes != null)
            {
                splitIndex = AdjustSplitPosition(currentIndex, splitIndex, prefixes, ref toRight);
            }

            var         currentKey = _page.GetNodeKey(splitIndex);
            MemorySlice seperatorKey;

            if (toRight && splitIndex == currentIndex)
            {
                seperatorKey = currentKey.Compare(_newKey) < 0 ? currentKey : _newKey;
            }
            else
            {
                seperatorKey = currentKey;
            }

            Page parentOfRight;

            AddSeparatorToParentPage(rightPage.PageNumber, seperatorKey, out parentOfRight);

            var parentOfPage = _cursor.CurrentPage;

            MemorySlice instance = _page.CreateNewEmptyKey();

            if (prefixes != null)
            {
                for (int i = 0; i < prefixes.Length; i++)
                {
                    var prefix = prefixes[i];

                    rightPage.WritePrefix(new Slice(prefix.ValuePtr, prefix.PrefixLength), i);
                }
            }

            bool addedAsImplicitRef = false;

            if (_page.IsBranch && toRight && 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, _tree.KeysPrefixing ? (MemorySlice)PrefixedSlice.BeforeAllKeys : Slice.BeforeAllKeys);
                addedAsImplicitRef = true;
            }

            // move the actual entries from page to right page
            ushort nKeys = _page.NumberOfEntries;

            for (int i = splitIndex; i < nKeys; i++)
            {
                NodeHeader *node = _page.GetNode(i);
                if (_page.IsBranch && rightPage.NumberOfEntries == 0)
                {
                    rightPage.CopyNodeDataToEndOfPage(node, _tree.KeysPrefixing ? (MemorySlice)PrefixedSlice.BeforeAllKeys : Slice.BeforeAllKeys);
                }
                else
                {
                    _page.SetNodeKey(node, ref instance);
                    var key = rightPage.PrepareKeyToInsert(instance, rightPage.NumberOfEntries);

                    rightPage.CopyNodeDataToEndOfPage(node, key);
                }
            }

            _page.Truncate(_tx, splitIndex);

            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 = toRight ? InsertNewKey(rightPage) : InsertNewKey(_page);
                }
                catch (InvalidOperationException e)
                {
                    if (e.Message.StartsWith("The page is full and cannot add an entry") == 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);
        }
예제 #22
0
        private void MoveBranchNode(Page parentPage, Page from, Page to)
        {
            Debug.Assert(from.IsBranch);

            var originalFromKey = to.PrepareKeyToInsert(GetActualKey(from, from.LastSearchPositionOrLastEntry), to.LastSearchPosition);

            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

                NodeHeader *actualKeyNode;
                var         implicitLeftKey  = GetActualKey(to, 0, out actualKeyNode);
                var         implicitLeftNode = to.GetNode(0);
                var         leftPageNumber   = implicitLeftNode->PageNumber;

                MemorySlice implicitLeftKeyToInsert;

                if (implicitLeftNode == actualKeyNode)
                {
                    // no need to create a prefix, just use the existing prefixed key from the node
                    // this also prevents from creating a prefix which is the full key given in 'implicitLeftKey'

                    if (_tree.KeysPrefixing)
                    {
                        implicitLeftKeyToInsert = new PrefixedSlice(actualKeyNode);
                    }
                    else
                    {
                        implicitLeftKeyToInsert = new Slice(actualKeyNode);
                    }
                }
                else
                {
                    implicitLeftKeyToInsert = to.PrepareKeyToInsert(implicitLeftKey, 1);
                }

                to.EnsureHasSpaceFor(_tx, implicitLeftKeyToInsert, -1);
                to.AddPageRefNode(1, implicitLeftKeyToInsert, leftPageNumber);

                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);
            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(parentPage, pageNumber, newSeparatorKey, pos);
        }
예제 #23
0
        private byte *SplitPageInHalf(Page rightPage)
        {
            int  currentIndex = _page.LastSearchPosition;
            bool newPosition  = true;
            int  splitIndex   = _page.NumberOfEntries / 2;

            if (currentIndex < splitIndex)
            {
                newPosition = false;
            }

            PrefixNode[] prefixes = null;

            if (_tree.KeysPrefixing && _page.HasPrefixes)
            {
                prefixes = _page.GetPrefixes();
            }

            if (_page.IsLeaf || prefixes != null)
            {
                splitIndex = AdjustSplitPosition(currentIndex, splitIndex, prefixes, ref newPosition);
            }

            var currentKey = _page.GetNodeKey(splitIndex);

            // here the current key is the separator key and can go either way, so
            // use newPosition to decide if it stays on the left node or moves to the right
            MemorySlice seperatorKey;

            if (currentIndex == splitIndex && newPosition)
            {
                seperatorKey = currentKey.Compare(_newKey) < 0 ? currentKey : _newKey;
            }
            else
            {
                seperatorKey = currentKey;
            }

            AddSeparatorToParentPage(rightPage.PageNumber, seperatorKey);

            MemorySlice instance = _page.CreateNewEmptyKey();

            if (prefixes != null)
            {
                for (int i = 0; i < prefixes.Length; i++)
                {
                    var prefix = prefixes[i];

                    rightPage.WritePrefix(new Slice(prefix.ValuePtr, prefix.PrefixLength), i);
                }
            }

            // move the actual entries from page to right page
            ushort nKeys = _page.NumberOfEntries;

            for (int i = splitIndex; i < nKeys; i++)
            {
                NodeHeader *node = _page.GetNode(i);
                if (_page.IsBranch && rightPage.NumberOfEntries == 0)
                {
                    rightPage.CopyNodeDataToEndOfPage(node, _tree.KeysPrefixing ? (MemorySlice)PrefixedSlice.BeforeAllKeys : Slice.BeforeAllKeys);
                }
                else
                {
                    _page.SetNodeKey(node, ref instance);
                    var key = rightPage.PrepareKeyToInsert(instance, rightPage.NumberOfEntries);

                    rightPage.CopyNodeDataToEndOfPage(node, key);
                }
            }
            _page.Truncate(_tx, splitIndex);

            // actually insert the new key
            try
            {
                return((currentIndex > splitIndex || newPosition && currentIndex == splitIndex)
                                        ? InsertNewKey(rightPage)
                                        : InsertNewKey(_page));
            }
            catch (InvalidOperationException e)
            {
                if (e.Message.StartsWith("The page is full and cannot add an entry"))
                {
                    var debugInfo = new StringBuilder();

                    debugInfo.AppendFormat("\r\n_tree.Name: {0}\r\n", _tree.Name);
                    debugInfo.AppendFormat("_newKey: {0}, _len: {1}, needed space: {2}\r\n", _newKey, _len, _page.GetRequiredSpace(_newKey, _len));
                    debugInfo.AppendFormat("currentKey: {0}, seperatorKey: {1}\r\n", currentKey, seperatorKey);
                    debugInfo.AppendFormat("currentIndex: {0}\r\n", currentIndex);
                    debugInfo.AppendFormat("splitIndex: {0}\r\n", splitIndex);
                    debugInfo.AppendFormat("newPosition: {0}\r\n", newPosition);

                    debugInfo.AppendFormat("_page info: flags - {0}, # of entries {1}, size left: {2}, calculated size left: {3}\r\n", _page.Flags, _page.NumberOfEntries, _page.SizeLeft, _page.CalcSizeLeft());

                    for (int i = 0; i < _page.NumberOfEntries; i++)
                    {
                        var node = _page.GetNode(i);
                        var key  = _page.GetNodeKey(node);
                        debugInfo.AppendFormat("{0} - {2} {1}\r\n", key,
                                               node->DataSize, node->Flags == NodeFlags.Data ? "Size" : "Page");
                    }

                    debugInfo.AppendFormat("rightPage info: flags - {0}, # of entries {1}, size left: {2}, calculated size left: {3}\r\n", rightPage.Flags, rightPage.NumberOfEntries, rightPage.SizeLeft, rightPage.CalcSizeLeft());

                    for (int i = 0; i < rightPage.NumberOfEntries; i++)
                    {
                        var node = rightPage.GetNode(i);
                        var key  = rightPage.GetNodeKey(node);
                        debugInfo.AppendFormat("{0} - {2} {1}\r\n", key,
                                               node->DataSize, node->Flags == NodeFlags.Data ? "Size" : "Page");
                    }

                    throw new InvalidOperationException(debugInfo.ToString(), e);
                }

                throw;
            }
        }