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package org.hsqldb;
import org.hsqldb.ParserDQL.CompileContext;
import org.hsqldb.index.Index;
import org.hsqldb.lib.ArrayUtil;
import org.hsqldb.lib.HsqlArrayList;
import org.hsqldb.lib.Iterator;
import org.hsqldb.lib.MultiValueHashMap;
import org.hsqldb.lib.OrderedHashSet;
import org.hsqldb.lib.OrderedIntHashSet;
/**
* Determines how JOIN and WHERE expressions are used in query
* processing and which indexes are used for table access.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 1.9.0
* @since 1.9.0
*/
public class RangeVariableResolver {
RangeVariable[] rangeVariables;
Expression conditions;
OrderedHashSet rangeVarSet = new OrderedHashSet();
CompileContext compileContext;
//
HsqlArrayList[] tempJoinExpressions;
HsqlArrayList[] joinExpressions;
HsqlArrayList[] whereExpressions;
HsqlArrayList queryExpressions = new HsqlArrayList();
//
Expression[] inExpressions;
boolean[] flags;
//
OrderedHashSet set = new OrderedHashSet();
//
OrderedIntHashSet colIndexSetEqual = new OrderedIntHashSet();
OrderedIntHashSet colIndexSetOther = new OrderedIntHashSet();
MultiValueHashMap map = new MultiValueHashMap();
int inExpressionCount = 0;
boolean hasOuterJoin = false;
RangeVariableResolver(RangeVariable[] rangeVars, Expression conditions,
CompileContext compileContext) {
this.rangeVariables = rangeVars;
this.conditions = conditions;
this.compileContext = compileContext;
for (int i = 0; i < rangeVars.length; i++) {
RangeVariable range = rangeVars[i];
rangeVarSet.add(range);
if (range.isLeftJoin || range.isRightJoin) {
hasOuterJoin = true;
}
}
inExpressions = new Expression[rangeVars.length];
flags = new boolean[rangeVars.length];
tempJoinExpressions = new HsqlArrayList[rangeVars.length];
for (int i = 0; i < rangeVars.length; i++) {
tempJoinExpressions[i] = new HsqlArrayList();
}
joinExpressions = new HsqlArrayList[rangeVars.length];
for (int i = 0; i < rangeVars.length; i++) {
joinExpressions[i] = new HsqlArrayList();
}
whereExpressions = new HsqlArrayList[rangeVars.length];
for (int i = 0; i < rangeVars.length; i++) {
whereExpressions[i] = new HsqlArrayList();
}
}
void processConditions() {
decomposeCondition(conditions, queryExpressions);
for (int i = 0; i < rangeVariables.length; i++) {
if (rangeVariables[i].nonIndexJoinCondition == null) {
continue;
}
decomposeCondition(rangeVariables[i].nonIndexJoinCondition,
tempJoinExpressions[i]);
rangeVariables[i].nonIndexJoinCondition = null;
}
conditions = null;
assignToLists();
expandConditions();
assignToRangeVariables();
processFullJoins();
}
/**
* Divides AND conditions and assigns
*/
static Expression decomposeCondition(Expression e,
HsqlArrayList conditions) {
if (e == null) {
return Expression.EXPR_TRUE;
}
Expression arg1 = e.getLeftNode();
Expression arg2 = e.getRightNode();
int type = e.getType();
if (type == OpTypes.AND) {
arg1 = decomposeCondition(arg1, conditions);
arg2 = decomposeCondition(arg2, conditions);
if (arg1 == Expression.EXPR_TRUE) {
return arg2;
}
if (arg2 == Expression.EXPR_TRUE) {
return arg1;
}
e.setLeftNode(arg1);
e.setRightNode(arg2);
return e;
} else if (type == OpTypes.EQUAL) {
if (arg1.getType() == OpTypes.ROW
&& arg2.getType() == OpTypes.ROW) {
for (int i = 0; i < arg1.nodes.length; i++) {
Expression part = new ExpressionLogical(arg1.nodes[i],
arg2.nodes[i]);
part.resolveTypes(null, null);
conditions.add(part);
}
return Expression.EXPR_TRUE;
}
}
if (e != Expression.EXPR_TRUE) {
conditions.add(e);
}
return Expression.EXPR_TRUE;
}
/**
* Assigns the conditions to separate lists
*/
void assignToLists() {
int lastOuterIndex = -1;
for (int i = 0; i < rangeVariables.length; i++) {
if (rangeVariables[i].isLeftJoin
|| rangeVariables[i].isRightJoin) {
lastOuterIndex = i;
}
if (lastOuterIndex == i) {
joinExpressions[i].addAll(tempJoinExpressions[i]);
} else {
for (int j = 0; j < tempJoinExpressions[i].size(); j++) {
assignToLists((Expression) tempJoinExpressions[i].get(j),
joinExpressions, lastOuterIndex + 1);
}
}
}
for (int i = 0; i < queryExpressions.size(); i++) {
assignToLists((Expression) queryExpressions.get(i),
whereExpressions, lastOuterIndex);
}
}
/**
* Assigns a single condition to the relevant list of conditions
*
* Parameter first indicates the first range variable to which condition
* can be assigned
*/
void assignToLists(Expression e, HsqlArrayList[] expressionLists,
int first) {
set.clear();
e.collectRangeVariables(rangeVariables, set);
int index = rangeVarSet.getLargestIndex(set);
// condition is independent of tables if no range variable is found
if (index == -1) {
index = 0;
}
// condition is assigned to first non-outer range variable
if (index < first) {
index = first;
}
expressionLists[index].add(e);
}
void expandConditions() {
expandConditions(whereExpressions, false);
expandConditions(joinExpressions, false);
}
void expandConditions(HsqlArrayList[] array, boolean isJoin) {
for (int i = 0; i < rangeVariables.length; i++) {
HsqlArrayList list = array[i];
map.clear();
set.clear();
boolean hasChain = false;
for (int j = 0; j < list.size(); j++) {
Expression e = (Expression) list.get(j);
if (!e.isColumnEqual
|| e.getLeftNode().getRangeVariable()
== e.getRightNode().getRangeVariable()) {
continue;
}
if (e.getLeftNode().getRangeVariable() == rangeVariables[i]) {
map.put(e.getLeftNode().getColumn(), e.getRightNode());
if (!set.add(e.getLeftNode().getColumn())) {
hasChain = true;
}
} else {
map.put(e.getRightNode().getColumn(), e.getLeftNode());
if (!set.add(e.getRightNode().getColumn())) {
hasChain = true;
}
}
}
if (hasChain && !(hasOuterJoin && isJoin)) {
Iterator keyIt = map.keySet().iterator();
while (keyIt.hasNext()) {
Object key = keyIt.next();
Iterator it = map.get(key);
set.clear();
while (it.hasNext()) {
set.add(it.next());
}
while (set.size() > 1) {
Expression e1 = (Expression) set.remove(set.size()
- 1);
for (int j = 0; j < set.size(); j++) {
Expression e2 = (Expression) set.get(j);
closeJoinChain(array, e1, e2);
}
}
}
}
}
}
void closeJoinChain(HsqlArrayList[] array, Expression e1, Expression e2) {
int idx1 = rangeVarSet.getIndex(e1.getRangeVariable());
int idx2 = rangeVarSet.getIndex(e2.getRangeVariable());
int index = idx1 > idx2 ? idx1
: idx2;
array[index].add(new ExpressionLogical(e1, e2));
}
/**
* Assigns conditions to range variables and converts suitable IN conditions
* to table lookup.
*/
void assignToRangeVariables() {
for (int i = 0; i < rangeVariables.length; i++) {
boolean isOuter = rangeVariables[i].isLeftJoin
|| rangeVariables[i].isRightJoin;
if (isOuter) {
assignToRangeVariable(rangeVariables[i], i,
joinExpressions[i], true);
assignToRangeVariable(rangeVariables[i], i,
whereExpressions[i], false);
} else {
joinExpressions[i].addAll(whereExpressions[i]);
assignToRangeVariable(rangeVariables[i], i,
joinExpressions[i], true);
}
if (rangeVariables[i].hasIndexCondition()
&& inExpressions[i] != null) {
if (!flags[i] && isOuter) {
rangeVariables[i].addWhereCondition(inExpressions[i]);
} else {
rangeVariables[i].addJoinCondition(inExpressions[i]);
}
inExpressions[i] = null;
inExpressionCount--;
}
}
if (inExpressionCount != 0) {
setInConditionsAsTables();
}
}
/**
* Assigns a set of conditions to a range variable.
*/
void assignToRangeVariable(RangeVariable rangeVar, int rangeVarIndex,
HsqlArrayList exprList, boolean isJoin) {
if (exprList.isEmpty()) {
return;
}
colIndexSetEqual.clear();
colIndexSetOther.clear();
for (int j = 0, size = exprList.size(); j < size; j++) {
Expression e = (Expression) exprList.get(j);
if (rangeVar.hasIndexCondition()) {
rangeVar.addCondition(e, isJoin);
exprList.set(j, null);
continue;
}
if (e.getIndexableExpression(rangeVar) == null) {
rangeVar.addCondition(e, isJoin);
exprList.set(j, null);
continue;
}
// can use index
int type = e.getType();
switch (type) {
default : {
int colIndex = e.getLeftNode().getColumnIndex();
colIndexSetOther.add(colIndex);
break;
}
case OpTypes.EQUAL :
if (e.exprSubType == OpTypes.ANY_QUANTIFIED) {
Index index = rangeVar.rangeTable.getIndexForColumn(
e.getLeftNode().nodes[0].getColumnIndex());
// code to disable IN optimisation
// index = null;
if (index != null
&& inExpressions[rangeVarIndex] == null) {
inExpressions[rangeVarIndex] = e;
inExpressionCount++;
} else {
rangeVar.addCondition(e, isJoin);
}
exprList.set(j, null);
continue;
}
// fall through
case OpTypes.IS_NULL : {
int colIndex = e.getLeftNode().getColumnIndex();
colIndexSetEqual.add(colIndex);
break;
}
case OpTypes.NOT : {
int colIndex =
e.getLeftNode().getLeftNode().getColumnIndex();
colIndexSetOther.add(colIndex);
break;
}
}
}
boolean isEqual = true;
Index idx = rangeVar.rangeTable.getIndexForColumns(colIndexSetEqual);
if (idx == null) {
isEqual = false;
idx = rangeVar.rangeTable.getIndexForColumns(colIndexSetOther);
}
// different procedure for subquery tables
if (idx == null && rangeVar.rangeTable.isSessionBased) {
if (!colIndexSetEqual.isEmpty()) {
int[] cols = colIndexSetEqual.toArray();
idx = rangeVar.rangeTable.getIndexForColumns(cols);
}
if (idx == null && !colIndexSetOther.isEmpty()) {
int[] cols = colIndexSetOther.toArray();
idx = rangeVar.rangeTable.getIndexForColumns(cols);
}
}
// no index found
if (idx == null) {
for (int j = 0, size = exprList.size(); j < size; j++) {
Expression e = (Expression) exprList.get(j);
if (e != null) {
rangeVar.addCondition(e, isJoin);
}
}
return;
}
// index found
int[] cols = idx.getColumns();
int colCount = cols.length;
if (isEqual && colCount > 1) {
Expression[] firstRowExpressions = new Expression[cols.length];
for (int j = 0; j < exprList.size(); j++) {
Expression e = (Expression) exprList.get(j);
if (e == null) {
continue;
}
int type = e.getType();
if (type == OpTypes.EQUAL) {
int offset =
ArrayUtil.find(cols, e.getLeftNode().getColumnIndex());
if (offset != -1 && firstRowExpressions[offset] == null) {
firstRowExpressions[offset] = e;
exprList.set(j, null);
continue;
}
}
// not used in index lookup
rangeVar.addCondition(e, isJoin);
exprList.set(j, null);
}
boolean hasNull = false;
for (int i = 0; i < firstRowExpressions.length; i++) {
Expression e = firstRowExpressions[i];
if (e == null) {
if (colCount == cols.length) {
colCount = i;
}
hasNull = true;
continue;
}
if (hasNull) {
rangeVar.addCondition(e, isJoin);
firstRowExpressions[i] = null;
}
}
rangeVar.addIndexCondition(firstRowExpressions, idx, colCount,
isJoin);
return;
}
for (int j = 0; j < exprList.size(); j++) {
Expression e = (Expression) exprList.get(j);
if (e == null) {
continue;
}
if (rangeVar.hasIndexCondition()) {
rangeVar.addCondition(e, isJoin);
exprList.set(j, null);
continue;
}
boolean isIndexed = false;
if (e.getType() == OpTypes.NOT
&& cols[0]
== e.getLeftNode().getLeftNode().getColumnIndex()) {
isIndexed = true;
}
if (cols[0] == e.getLeftNode().getColumnIndex()) {
if (e.getRightNode() != null
&& !e.getRightNode().isCorrelated()) {
isIndexed = true;
}
if (e.getType() == OpTypes.IS_NULL) {
isIndexed = true;
}
}
if (isIndexed) {
rangeVar.addIndexCondition(e, idx, isJoin);
} else {
rangeVar.addCondition(e, isJoin);
}
exprList.set(j, null);
}
}
/**
* Converts an IN conditions into a JOIN
*/
void setInConditionsAsTables() {
for (int i = rangeVariables.length - 1; i >= 0; i--) {
RangeVariable rangeVar = rangeVariables[i];
Expression in = inExpressions[i];
if (in != null) {
Index index = rangeVar.rangeTable.getIndexForColumn(
in.getLeftNode().nodes[0].getColumnIndex());
RangeVariable newRangeVar =
new RangeVariable(in.getRightNode().subQuery.getTable(),
null, null, null, compileContext);
RangeVariable[] newList =
new RangeVariable[rangeVariables.length + 1];
ArrayUtil.copyAdjustArray(rangeVariables, newList,
newRangeVar, i, 1);
rangeVariables = newList;
// make two columns as arg
ColumnSchema left = rangeVar.rangeTable.getColumn(
in.getLeftNode().nodes[0].getColumnIndex());
ColumnSchema right = newRangeVar.rangeTable.getColumn(0);
Expression e = new ExpressionLogical(rangeVar, left,
newRangeVar, right);
rangeVar.addIndexCondition(e, index, flags[i]);
}
}
}
void processFullJoins() {
for (int i = 0; i < rangeVariables.length; i++) {
if (rangeVariables[i].isRightJoin) {}
}
}
}