public void onMatch(RelOptRuleCall call) {
CalcRel calc = (CalcRel) call.getRels()[0];
RexProgram program = calc.getProgram();
final List<RexNode> exprList = program.getExprList();
// Form a list of expressions with sub-expressions fully
// expanded.
final List<RexNode> expandedExprList = new ArrayList<RexNode>(exprList.size());
final RexShuttle shuttle =
new RexShuttle() {
public RexNode visitLocalRef(RexLocalRef localRef) {
return expandedExprList.get(localRef.getIndex());
}
};
for (RexNode expr : exprList) {
expandedExprList.add(expr.accept(shuttle));
}
if (reduceExpressions(calc, expandedExprList)) {
final RexProgramBuilder builder =
new RexProgramBuilder(
calc.getChild().getRowType(), calc.getCluster().getRexBuilder());
List<RexLocalRef> list = new ArrayList<RexLocalRef>();
for (RexNode expr : expandedExprList) {
list.add(builder.registerInput(expr));
}
if (program.getCondition() != null) {
final int conditionIndex = program.getCondition().getIndex();
final RexNode newConditionExp = expandedExprList.get(conditionIndex);
if (newConditionExp.isAlwaysTrue()) {
// condition is always TRUE - drop it
} else if ((newConditionExp instanceof RexLiteral)
|| RexUtil.isNullLiteral(newConditionExp, true)) {
// condition is always NULL or FALSE - replace calc
// with empty
call.transformTo(new EmptyRel(calc.getCluster(), calc.getRowType()));
return;
} else {
builder.addCondition(list.get(conditionIndex));
}
}
int k = 0;
for (RexLocalRef projectExpr : program.getProjectList()) {
final int index = projectExpr.getIndex();
builder.addProject(
list.get(index).getIndex(),
program.getOutputRowType().getFieldList().get(k++).getName());
}
call.transformTo(
new CalcRel(
calc.getCluster(),
calc.getTraits(),
calc.getChild(),
calc.getRowType(),
builder.getProgram(),
calc.getCollationList()));
// New plan is absolutely better than old plan.
call.getPlanner().setImportance(calc, 0.0);
}
}
// implement RelOptRule
public void onMatch(RelOptRuleCall call) {
CalcRel calcRel = (CalcRel) call.rels[0];
RexProgram program = calcRel.getProgram();
// check the projection
List<Integer> projOrdinals = new ArrayList<Integer>();
RelDataType outputRowType = isProjectSimple(calcRel, projOrdinals);
if (outputRowType == null) {
return;
}
RexLocalRef condition = program.getCondition();
CompOperatorEnum compOp = CompOperatorEnum.COMP_NOOP;
Integer[] filterOrdinals = {};
List<RexLiteral> filterLiterals = new ArrayList<RexLiteral>();
// check the condition
if (condition != null) {
RexNode filterExprs = program.expandLocalRef(condition);
List<Integer> filterList = new ArrayList<Integer>();
List<CompOperatorEnum> op = new ArrayList<CompOperatorEnum>();
if (!isConditionSimple(calcRel, filterExprs, filterList, filterLiterals, op)) {
return;
}
compOp = op.get(0);
filterOrdinals = filterList.toArray(new Integer[filterList.size()]);
}
RelNode fennelInput =
mergeTraitsAndConvert(
calcRel.getTraits(), FennelRel.FENNEL_EXEC_CONVENTION, calcRel.getChild());
if (fennelInput == null) {
return;
}
Integer[] projection = projOrdinals.toArray(new Integer[projOrdinals.size()]);
FennelReshapeRel reshapeRel =
new FennelReshapeRel(
calcRel.getCluster(),
fennelInput,
projection,
outputRowType,
compOp,
filterOrdinals,
filterLiterals,
new FennelRelParamId[] {},
new Integer[] {},
null);
call.transformTo(reshapeRel);
}
/**
* Creates a relational expression which permutes the output fields of a relational expression
* according to a permutation.
*
* <p>Optimizations:
*
* <ul>
* <li>If the relational expression is a {@link CalcRel} or {@link ProjectRel} which is already
* acting as a permutation, combines the new permutation with the old;
* <li>If the permutation is the identity, returns the original relational expression.
* </ul>
*
* <p>If a permutation is combined with its inverse, these optimizations would combine to remove
* them both.
*
* @param rel Relational expression
* @param permutation Permutation to apply to fields
* @param fieldNames Field names; if null, or if a particular entry is null, the name of the
* permuted field is used
* @return relational expression which permutes its input fields
*/
public static RelNode permute(RelNode rel, Permutation permutation, List<String> fieldNames) {
if (permutation.isIdentity()) {
return rel;
}
if (rel instanceof CalcRel) {
CalcRel calcRel = (CalcRel) rel;
Permutation permutation1 = calcRel.getProgram().getPermutation();
if (permutation1 != null) {
Permutation permutation2 = permutation.product(permutation1);
return permute(rel, permutation2, null);
}
}
if (rel instanceof ProjectRel) {
Permutation permutation1 = ((ProjectRel) rel).getPermutation();
if (permutation1 != null) {
Permutation permutation2 = permutation.product(permutation1);
return permute(rel, permutation2, null);
}
}
final List<RelDataType> outputTypeList = new ArrayList<RelDataType>();
final List<String> outputNameList = new ArrayList<String>();
final List<RexNode> exprList = new ArrayList<RexNode>();
final List<RexLocalRef> projectRefList = new ArrayList<RexLocalRef>();
final List<RelDataTypeField> fields = rel.getRowType().getFieldList();
for (int i = 0; i < permutation.getTargetCount(); i++) {
int target = permutation.getTarget(i);
final RelDataTypeField targetField = fields.get(target);
outputTypeList.add(targetField.getType());
outputNameList.add(
((fieldNames == null) || (fieldNames.size() <= i) || (fieldNames.get(i) == null))
? targetField.getName()
: fieldNames.get(i));
exprList.add(rel.getCluster().getRexBuilder().makeInputRef(fields.get(i).getType(), i));
final int source = permutation.getSource(i);
projectRefList.add(new RexLocalRef(source, fields.get(source).getType()));
}
final RexProgram program =
new RexProgram(
rel.getRowType(),
exprList,
projectRefList,
null,
rel.getCluster().getTypeFactory().createStructType(outputTypeList, outputNameList));
return new CalcRel(
rel.getCluster(),
rel.getTraitSet(),
rel,
program.getOutputRowType(),
program,
Collections.<RelCollation>emptyList());
}
/**
* Determines if a projection is simple.
*
* @param calcRel CalcRel containing the projection
* @param projOrdinals if the projection is simple, returns the ordinals of the projection inputs
* @return rowtype corresponding to the projection, provided it is simple; otherwise null is
* returned
*/
private RelDataType isProjectSimple(CalcRel calcRel, List<Integer> projOrdinals) {
// Loop through projection expressions. If we find a non-simple
// projection expression, simply return.
RexProgram program = calcRel.getProgram();
List<RexLocalRef> projList = program.getProjectList();
int nProjExprs = projList.size();
RelDataType[] types = new RelDataType[nProjExprs];
String[] fieldNames = new String[nProjExprs];
RelDataTypeField[] projFields = calcRel.getRowType().getFields();
for (int i = 0; i < nProjExprs; i++) {
RexNode projExpr = program.expandLocalRef(projList.get(i));
if (projExpr instanceof RexInputRef) {
projOrdinals.add(((RexInputRef) projExpr).getIndex());
types[i] = projExpr.getType();
fieldNames[i] = projFields[i].getName();
continue;
} else if (!(projExpr instanceof RexCall)) {
return null;
}
RexCall rexCall = (RexCall) projExpr;
if (rexCall.getOperator() != SqlStdOperatorTable.castFunc) {
return null;
}
RexNode castOperand = rexCall.getOperands()[0];
if (!(castOperand instanceof RexInputRef)) {
return null;
}
RelDataType castType = projExpr.getType();
RelDataType origType = castOperand.getType();
if (isCastSimple(origType, castType)) {
projOrdinals.add(((RexInputRef) castOperand).getIndex());
types[i] = castType;
fieldNames[i] = projFields[i].getName();
} else {
return null;
}
}
// return the rowtype corresponding to the output of the projection
return calcRel.getCluster().getTypeFactory().createStructType(types, fieldNames);
}