public void DeleteTree(Transaction tx, string name)
{
if (tx.Flags == (TransactionFlags.ReadWrite) == false)
throw new ArgumentException("Cannot create a new newRootTree with a read only transaction");
Tree tree = tx.ReadTree(name);
if (tree == null)
return;
foreach (var page in tree.AllPages())
{
tx.FreePage(page);
}
tx.State.Root.Delete((Slice) name);
tx.RemoveTree(name);
}
private bool TryOverwriteOverflowPages(Transaction tx, TreeMutableState treeState, NodeHeader* updatedNode,
Slice key, int len, ushort? version, out byte* pos)
{
if (updatedNode->Flags == NodeFlags.PageRef &&
tx.Id <= tx.Environment.OldestTransaction) // ensure MVCC - do not overwrite if there is some older active transaction that might read those overflows
{
var overflowPage = tx.GetReadOnlyPage(updatedNode->PageNumber);
if (len <= overflowPage.OverflowSize)
{
CheckConcurrency(key, version, updatedNode->Version, TreeActionType.Add);
if (updatedNode->Version == ushort.MaxValue)
updatedNode->Version = 0;
updatedNode->Version++;
var availableOverflows = tx.DataPager.GetNumberOfOverflowPages(overflowPage.OverflowSize);
var requestedOverflows = tx.DataPager.GetNumberOfOverflowPages(len);
var overflowsToFree = availableOverflows - requestedOverflows;
for (int i = 0; i < overflowsToFree; i++)
{
tx.FreePage(overflowPage.PageNumber + requestedOverflows + i);
}
treeState.OverflowPages -= overflowsToFree;
treeState.PageCount -= overflowsToFree;
overflowPage.OverflowSize = len;
pos = overflowPage.Base + Constants.PageHeaderSize;
return true;
}
}
pos = null;
return false;
}
public void MultiDelete(Transaction tx, Slice key, Slice value, ushort? version = null)
{
State.IsModified = true;
Lazy<Cursor> lazy;
var page = FindPageFor(tx, key, out lazy);
if (page == null || page.LastMatch != 0)
{
return; //nothing to delete - key not found
}
page = tx.ModifyPage(page.PageNumber, page);
var item = page.GetNode(page.LastSearchPosition);
if (item->Flags == NodeFlags.MultiValuePageRef) //multi-value tree exists
{
var tree = OpenOrCreateMultiValueTree(tx, key, item);
tree.Delete(tx, 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.EntriesCount != 0)
return;
tx.TryRemoveMultiValueTree(this, key);
tx.FreePage(tree.State.RootPageNumber);
Delete(tx, key);
}
else // we use a nested page here
{
var nestedPage = new Page(NodeHeader.DirectAccess(tx, item), "multi tree", (ushort)NodeHeader.GetDataSize(tx, item));
var nestedItem = nestedPage.Search(value, NativeMethods.memcmp);
if (nestedItem == null) // value not found
return;
CheckConcurrency(key, value, version, nestedItem->Version, TreeActionType.Delete);
nestedPage.RemoveNode(nestedPage.LastSearchPosition);
if (nestedPage.NumberOfEntries == 0)
Delete(tx, key);
}
}
private void RemoveLeafNode(Transaction tx, Page page, out ushort nodeVersion)
{
var node = page.GetNode(page.LastSearchPosition);
nodeVersion = node->Version;
if (node->Flags == (NodeFlags.PageRef)) // this is an overflow pointer
{
var overflowPage = tx.GetReadOnlyPage(node->PageNumber);
var numberOfPages = tx.DataPager.GetNumberOfOverflowPages(overflowPage.OverflowSize);
for (int i = 0; i < numberOfPages; i++)
{
tx.FreePage(overflowPage.PageNumber + i);
}
State.OverflowPages -= numberOfPages;
State.PageCount -= numberOfPages;
}
page.RemoveNode(page.LastSearchPosition);
}
public void MultiDelete(Transaction tx, Slice key, Slice value, ushort? version = null)
{
State.IsModified = true;
Lazy<Cursor> lazy;
var page = FindPageFor(tx, key, out lazy);
if (page == null || page.LastMatch != 0)
{
return; //nothing to delete - key not found
}
page = tx.ModifyPage(page.PageNumber, page);
var item = page.GetNode(page.LastSearchPosition);
if (item->Flags == NodeFlags.MultiValuePageRef) //multi-value tree exists
{
var tree = OpenOrCreateMultiValueTree(tx, key, item);
tree.Delete(tx, value, version);
if (tree.State.EntriesCount > 1)
return;
// convert back to simple key/val
var iterator = tree.Iterate(tx);
if (!iterator.Seek(Slice.BeforeAllKeys))
throw new InvalidDataException(
"MultiDelete() failed : sub-tree is empty where it should not be, this is probably a Voron bug.");
var dataToSave = iterator.CurrentKey;
var ptr = DirectAdd(tx, key, dataToSave.Size);
dataToSave.CopyTo(ptr);
tx.TryRemoveMultiValueTree(this, key);
tx.FreePage(tree.State.RootPageNumber);
}
else //the regular key->value pattern
{
Delete(tx, key, version);
}
}