void
GiST::InsertHelper(const GiSTentry &entry,
int level, // level of tree at which to insert
int *splitvec) // a vector to trigger Split instead of forced reinsert
{
GiSTnode *leaf;
int overflow=0;
leaf=ChooseSubtree(GiSTRootPage, entry, level);
leaf->Insert(entry);
if (leaf->IsOverFull(*store)) {
if(ForcedReinsert()&&!leaf->Path().IsRoot()&&(!splitvec||!splitvec[level])) {
int split[GIST_MAX_LEVELS];
// R*-tree-style forced reinsert
for(int i=0; i<GIST_MAX_LEVELS; i++) split[i]=0;
OverflowTreatment(leaf, entry, split);
overflow=1;
}
else Split(&leaf, entry);
if(leaf->IsOverFull(*store)) {
// we only should get here if we reinserted, and the node re-filled
assert(overflow);
leaf->DeleteEntry(entry.Position());
Split(&leaf, entry);
}
}
else WriteNode(leaf);
if(!overflow) AdjustKeys(leaf, NULL);
delete leaf;
}
void
GiST::AdjustKeys (GiSTnode *node, GiSTnode **parent)
{
if (node->Path().IsRoot()) {
return;
}
GiSTnode *P;
// Read in node's parent
if (parent == NULL) {
GiSTpath parent_path = node->Path();
parent_path.MakeParent ();
P = ReadNode (parent_path);
parent = &P;
} else {
P = *parent;
}
// Get the old entry pointing to node
GiSTentry *entry = P->SearchPtr(node->Path().Page());
assert (entry != NULL);
// Get union of node
GiSTentry *actual = node->Union();
WriteNode(node); // added by myself for the splitted = false;
actual->SetPtr(node->Path().Page());
if (!entry->IsEqual(*actual)) {
int pos = entry->Position();
P->DeleteEntry(pos);
P->InsertBefore(*actual, pos);
// A split may be necessary.
// XXX: should we do Forced Reinsert here too?
if (P->IsOverFull(*store)) {
Split (parent, *actual);
GiSTpage page = node->Path().Page();
node->Path() = P->Path();
node->Path().MakeChild(page);
} else {
WriteNode (P);
AdjustKeys (P, NULL);
}
}
if (parent == &P) {
delete P;
}
delete actual;
delete entry;
}
void
GiST::OverflowTreatment (GiSTnode *node, const GiSTentry& entry, int *splitvec)
{
// remove the "top" p entries from the node
GiSTlist<GiSTentry*> deleted = RemoveTop (node);
WriteNode (node);
AdjustKeys (node, NULL);
// note that we've seen this level already
splitvec[node->Level()] = 1;
// for each of the deleted entries, call InsertHelper at this level
while (!deleted.IsEmpty()) {
GiSTentry *tmpentry = deleted.RemoveFront ();
InsertHelper (*tmpentry, node->Level(), splitvec);
delete tmpentry;
}
}
// handle underfull leaf nodes
int
GiST::CondenseTree(GiSTnode *node)
{
GiSTlist<GiSTentry*> Q;
int deleted=0;
// Must be condensing a leaf
assert(node->IsLeaf());
while(!node->Path().IsRoot()) {
GiSTpath parent_path=node->Path();
parent_path.MakeParent();
GiSTnode *P=ReadNode(parent_path);
GiSTentry *En=P->SearchPtr(node->Path().Page());
assert(En!=NULL);
// Handle under-full node
if(node->IsUnderFull(*store)) {
if(!IsOrdered()) {
TruePredicate truePredicate;
GiSTlist<GiSTentry*> list=node->Search(truePredicate);
while(!list.IsEmpty()) {
GiSTentry *e=list.RemoveFront();
Q.Append(e);
}
P->DeleteEntry(En->Position());
WriteNode(P);
deleted=1;
AdjustKeys(P, NULL);
}
else {
// Try to borrow entries, else coalesce with a neighbor
// Have to look at left sibling???
GiSTpage neighbor_page=P->SearchNeighbors(node->Path().Page());
GiSTpath neighbor_path=node->Path();
neighbor_path.MakeSibling(neighbor_page);
if(neighbor_page!=0) {
GiSTnode *neighbor;
// If neighbor is RIGHT sibling...
if(node->Sibling()==neighbor_page) neighbor=ReadNode(neighbor_path);
else {
neighbor=node;
node=ReadNode(neighbor_path);
}
GiSTentry *e=P->SearchPtr(node->Path().Page());
node->Coalesce(*neighbor, *e);
delete e;
// If not overfull, coalesce, kill right node
if(!node->IsOverFull(*store)) {
node->SetSibling(neighbor->Sibling());
WriteNode(node);
// Delete the neighbor from parent
GiSTentry *e=P->SearchPtr(neighbor->Path().Page());
P->DeleteEntry(e->Position());
WriteNode(P);
delete e;
store->Deallocate(neighbor->Path().Page());
deleted=1;
}
// If overfull, split (same as borrowing)
else {
GiSTnode *node2=node->PickSplit();
node2->Path()=neighbor->Path();
node2->SetSibling(neighbor->Sibling());
WriteNode(node);
WriteNode(node2);
AdjustKeys(node2, &P);
delete node2;
deleted=1;
}
delete neighbor;
}
}
}
// Adjust covering predicate
if(!deleted) AdjustKeys(node, &P);
parent_path=node->Path();
parent_path.MakeParent();
delete node;
// Propagate deletes
if(!deleted) break;
node=P;
}
// Re-insert orphaned entries
while(!Q.IsEmpty()) {
GiSTentry *e=Q.RemoveFront();
InsertHelper(*e, e->Level());
delete e;
}
return(deleted);
}