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/* Copyright (C) 2003 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#define DBTUX_SEARCH_CPP
#include "Dbtux.hpp"
/*
* Search for entry to add.
*
* Similar to searchToRemove (see below).
*/
bool
Dbtux::searchToAdd(Frag& frag, ConstData searchKey, TreeEnt searchEnt, TreePos& treePos)
{
const TreeHead& tree = frag.m_tree;
const unsigned numAttrs = frag.m_numAttrs;
NodeHandle currNode(frag);
currNode.m_loc = tree.m_root;
if (currNode.m_loc == NullTupLoc) {
// empty tree
jam();
return true;
}
NodeHandle glbNode(frag); // potential g.l.b of final node
/*
* In order to not (yet) change old behaviour, a position between
* 2 nodes returns the one at the bottom of the tree.
*/
NodeHandle bottomNode(frag);
while (true) {
jam();
selectNode(currNode, currNode.m_loc);
int ret;
// compare prefix
unsigned start = 0;
ret = cmpSearchKey(frag, start, searchKey, currNode.getPref(), tree.m_prefSize);
if (ret == NdbSqlUtil::CmpUnknown) {
jam();
// read and compare remaining attributes
ndbrequire(start < numAttrs);
readKeyAttrs(frag, currNode.getMinMax(0), start, c_entryKey);
ret = cmpSearchKey(frag, start, searchKey, c_entryKey);
ndbrequire(ret != NdbSqlUtil::CmpUnknown);
}
if (ret == 0) {
jam();
// keys are equal, compare entry values
ret = searchEnt.cmp(currNode.getMinMax(0));
}
if (ret < 0) {
jam();
const TupLoc loc = currNode.getLink(0);
if (loc != NullTupLoc) {
jam();
// continue to left subtree
currNode.m_loc = loc;
continue;
}
if (! glbNode.isNull()) {
jam();
// move up to the g.l.b but remember the bottom node
bottomNode = currNode;
currNode = glbNode;
}
} else if (ret > 0) {
jam();
const TupLoc loc = currNode.getLink(1);
if (loc != NullTupLoc) {
jam();
// save potential g.l.b
glbNode = currNode;
// continue to right subtree
currNode.m_loc = loc;
continue;
}
} else {
jam();
treePos.m_loc = currNode.m_loc;
treePos.m_pos = 0;
// entry found - error
return false;
}
break;
}
// anticipate
treePos.m_loc = currNode.m_loc;
// binary search
int lo = -1;
int hi = currNode.getOccup();
int ret;
while (1) {
jam();
// hi - lo > 1 implies lo < j < hi
int j = (hi + lo) / 2;
// read and compare attributes
unsigned start = 0;
readKeyAttrs(frag, currNode.getEnt(j), start, c_entryKey);
ret = cmpSearchKey(frag, start, searchKey, c_entryKey);
ndbrequire(ret != NdbSqlUtil::CmpUnknown);
if (ret == 0) {
jam();
// keys are equal, compare entry values
ret = searchEnt.cmp(currNode.getEnt(j));
}
if (ret < 0)
hi = j;
else if (ret > 0)
lo = j;
else {
treePos.m_pos = j;
// entry found - error
return false;
}
if (hi - lo == 1)
break;
}
if (ret < 0) {
jam();
treePos.m_pos = hi;
return true;
}
if ((uint) hi < currNode.getOccup()) {
jam();
treePos.m_pos = hi;
return true;
}
if (bottomNode.isNull()) {
jam();
treePos.m_pos = hi;
return true;
}
jam();
// backwards compatible for now
treePos.m_loc = bottomNode.m_loc;
treePos.m_pos = 0;
return true;
}
/*
* Search for entry to remove.
*
* Compares search key to each node min. A move to right subtree can
* overshoot target node. The last such node is saved. The final node
* is a semi-leaf or leaf. If search key is less than final node min
* then the saved node is the g.l.b of the final node and we move back
* to it.
*/
bool
Dbtux::searchToRemove(Frag& frag, ConstData searchKey, TreeEnt searchEnt, TreePos& treePos)
{
const TreeHead& tree = frag.m_tree;
const unsigned numAttrs = frag.m_numAttrs;
NodeHandle currNode(frag);
currNode.m_loc = tree.m_root;
if (currNode.m_loc == NullTupLoc) {
// empty tree - failed
jam();
return false;
}
NodeHandle glbNode(frag); // potential g.l.b of final node
while (true) {
jam();
selectNode(currNode, currNode.m_loc);
int ret;
// compare prefix
unsigned start = 0;
ret = cmpSearchKey(frag, start, searchKey, currNode.getPref(), tree.m_prefSize);
if (ret == NdbSqlUtil::CmpUnknown) {
jam();
// read and compare remaining attributes
ndbrequire(start < numAttrs);
readKeyAttrs(frag, currNode.getMinMax(0), start, c_entryKey);
ret = cmpSearchKey(frag, start, searchKey, c_entryKey);
ndbrequire(ret != NdbSqlUtil::CmpUnknown);
}
if (ret == 0) {
jam();
// keys are equal, compare entry values
ret = searchEnt.cmp(currNode.getMinMax(0));
}
if (ret < 0) {
jam();
const TupLoc loc = currNode.getLink(0);
if (loc != NullTupLoc) {
jam();
// continue to left subtree
currNode.m_loc = loc;
continue;
}
if (! glbNode.isNull()) {
jam();
// move up to the g.l.b
currNode = glbNode;
}
} else if (ret > 0) {
jam();
const TupLoc loc = currNode.getLink(1);
if (loc != NullTupLoc) {
jam();
// save potential g.l.b
glbNode = currNode;
// continue to right subtree
currNode.m_loc = loc;
continue;
}
} else {
jam();
treePos.m_loc = currNode.m_loc;
treePos.m_pos = 0;
return true;
}
break;
}
// anticipate
treePos.m_loc = currNode.m_loc;
// pos 0 was handled above
for (unsigned j = 1, occup = currNode.getOccup(); j < occup; j++) {
jam();
// compare only the entry
if (searchEnt.eq(currNode.getEnt(j))) {
jam();
treePos.m_pos = j;
return true;
}
}
treePos.m_pos = currNode.getOccup();
// not found - failed
return false;
}
/*
* Search for scan start position.
*
* Similar to searchToAdd. The routines differ somewhat depending on
* scan direction and are done by separate methods.
*/
void
Dbtux::searchToScan(Frag& frag, ConstData boundInfo, unsigned boundCount, bool descending, TreePos& treePos)
{
const TreeHead& tree = frag.m_tree;
if (tree.m_root != NullTupLoc) {
if (! descending)
searchToScanAscending(frag, boundInfo, boundCount, treePos);
else
searchToScanDescending(frag, boundInfo, boundCount, treePos);
return;
}
// empty tree
}
void
Dbtux::searchToScanAscending(Frag& frag, ConstData boundInfo, unsigned boundCount, TreePos& treePos)
{
const TreeHead& tree = frag.m_tree;
NodeHandle currNode(frag);
currNode.m_loc = tree.m_root;
NodeHandle glbNode(frag); // potential g.l.b of final node
NodeHandle bottomNode(frag);
while (true) {
jam();
selectNode(currNode, currNode.m_loc);
int ret;
// compare prefix
ret = cmpScanBound(frag, 0, boundInfo, boundCount, currNode.getPref(), tree.m_prefSize);
if (ret == NdbSqlUtil::CmpUnknown) {
jam();
// read and compare all attributes
readKeyAttrs(frag, currNode.getMinMax(0), 0, c_entryKey);
ret = cmpScanBound(frag, 0, boundInfo, boundCount, c_entryKey);
ndbrequire(ret != NdbSqlUtil::CmpUnknown);
}
if (ret < 0) {
// bound is left of this node
jam();
const TupLoc loc = currNode.getLink(0);
if (loc != NullTupLoc) {
jam();
// continue to left subtree
currNode.m_loc = loc;
continue;
}
if (! glbNode.isNull()) {
jam();
// move up to the g.l.b but remember the bottom node
bottomNode = currNode;
currNode = glbNode;
} else {
// start scanning this node
treePos.m_loc = currNode.m_loc;
treePos.m_pos = 0;
treePos.m_dir = 3;
return;
}
} else {
// bound is at or right of this node
jam();
const TupLoc loc = currNode.getLink(1);
if (loc != NullTupLoc) {
jam();
// save potential g.l.b
glbNode = currNode;
// continue to right subtree
currNode.m_loc = loc;
continue;
}
}
break;
}
for (unsigned j = 0, occup = currNode.getOccup(); j < occup; j++) {
jam();
int ret;
// read and compare attributes
readKeyAttrs(frag, currNode.getEnt(j), 0, c_entryKey);
ret = cmpScanBound(frag, 0, boundInfo, boundCount, c_entryKey);
ndbrequire(ret != NdbSqlUtil::CmpUnknown);
if (ret < 0) {
// found first entry satisfying the bound
treePos.m_loc = currNode.m_loc;
treePos.m_pos = j;
treePos.m_dir = 3;
return;
}
}
// bound is to right of this node
if (! bottomNode.isNull()) {
jam();
// start scanning the l.u.b
treePos.m_loc = bottomNode.m_loc;
treePos.m_pos = 0;
treePos.m_dir = 3;
return;
}
// start scanning upwards (pretend we came from right child)
treePos.m_loc = currNode.m_loc;
treePos.m_dir = 1;
}
void
Dbtux::searchToScanDescending(Frag& frag, ConstData boundInfo, unsigned boundCount, TreePos& treePos)
{
const TreeHead& tree = frag.m_tree;
NodeHandle currNode(frag);
currNode.m_loc = tree.m_root;
NodeHandle glbNode(frag); // potential g.l.b of final node
NodeHandle bottomNode(frag);
while (true) {
jam();
selectNode(currNode, currNode.m_loc);
int ret;
// compare prefix
ret = cmpScanBound(frag, 1, boundInfo, boundCount, currNode.getPref(), tree.m_prefSize);
if (ret == NdbSqlUtil::CmpUnknown) {
jam();
// read and compare all attributes
readKeyAttrs(frag, currNode.getMinMax(0), 0, c_entryKey);
ret = cmpScanBound(frag, 1, boundInfo, boundCount, c_entryKey);
ndbrequire(ret != NdbSqlUtil::CmpUnknown);
}
if (ret < 0) {
// bound is left of this node
jam();
const TupLoc loc = currNode.getLink(0);
if (loc != NullTupLoc) {
jam();
// continue to left subtree
currNode.m_loc = loc;
continue;
}
if (! glbNode.isNull()) {
jam();
// move up to the g.l.b but remember the bottom node
bottomNode = currNode;
currNode = glbNode;
} else {
// empty result set
return;
}
} else {
// bound is at or right of this node
jam();
const TupLoc loc = currNode.getLink(1);
if (loc != NullTupLoc) {
jam();
// save potential g.l.b
glbNode = currNode;
// continue to right subtree
currNode.m_loc = loc;
continue;
}
}
break;
}
for (unsigned j = 0, occup = currNode.getOccup(); j < occup; j++) {
jam();
int ret;
// read and compare attributes
readKeyAttrs(frag, currNode.getEnt(j), 0, c_entryKey);
ret = cmpScanBound(frag, 1, boundInfo, boundCount, c_entryKey);
ndbrequire(ret != NdbSqlUtil::CmpUnknown);
if (ret < 0) {
if (j > 0) {
// start scanning from previous entry
treePos.m_loc = currNode.m_loc;
treePos.m_pos = j - 1;
treePos.m_dir = 3;
return;
}
// start scanning upwards (pretend we came from left child)
treePos.m_loc = currNode.m_loc;
treePos.m_pos = 0;
treePos.m_dir = 0;
return;
}
}
// start scanning this node
treePos.m_loc = currNode.m_loc;
treePos.m_pos = currNode.getOccup() - 1;
treePos.m_dir = 3;
}
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