private void addResult(RexNode exp) {
// Cast of literal can't be reduced, so skip those (otherwise we'd
// go into an infinite loop as we add them back).
if (exp.getKind() == RexKind.Cast) {
RexCall cast = (RexCall) exp;
RexNode operand = cast.getOperands()[0];
if (operand instanceof RexLiteral) {
return;
}
}
constExprs.add(exp);
// In the case where the expression corresponds to a UDR argument,
// we need to preserve casts. Note that this only applies to
// the topmost argument, not expressions nested within the UDR
// call.
//
// REVIEW zfong 6/13/08 - Are there other expressions where we
// also need to preserve casts?
if (parentCallTypeStack.isEmpty()) {
addCasts.add(false);
} else {
addCasts.add(
parentCallTypeStack.get(parentCallTypeStack.size() - 1)
instanceof FarragoUserDefinedRoutine);
}
}
private void reduceNotNullableFilter(
RelOptRuleCall call, FilterRel filter, RexCall rexCall, boolean reverse) {
// If the expression is a IS [NOT] NULL on a non-nullable
// column, then we can either remove the filter or replace
// it with an EmptyRel.
SqlOperator op = rexCall.getOperator();
boolean alwaysTrue;
if (op == SqlStdOperatorTable.isNullOperator
|| op == SqlStdOperatorTable.isUnknownOperator) {
alwaysTrue = false;
} else if (op == SqlStdOperatorTable.isNotNullOperator) {
alwaysTrue = true;
} else {
return;
}
if (reverse) {
alwaysTrue = !alwaysTrue;
}
RexNode operand = rexCall.getOperands()[0];
if (operand instanceof RexInputRef) {
RexInputRef inputRef = (RexInputRef) operand;
if (!inputRef.getType().isNullable()) {
if (alwaysTrue) {
call.transformTo(filter.getChild());
} else {
call.transformTo(new EmptyRel(filter.getCluster(), filter.getRowType()));
}
}
}
}
private Expression translate0(RexNode expr) {
if (expr instanceof RexInputRef) {
// TODO: multiple inputs, e.g. joins
final Expression input = getInput(0);
final int index = ((RexInputRef) expr).getIndex();
final List<RelDataTypeField> fields = program.getInputRowType().getFieldList();
final RelDataTypeField field = fields.get(index);
if (fields.size() == 1) {
return input;
} else if (input.getType() == Object[].class) {
return Expressions.convert_(
Expressions.arrayIndex(input, Expressions.constant(field.getIndex())),
Types.box(JavaRules.EnumUtil.javaClass(typeFactory, field.getType())));
} else {
return Expressions.field(input, field.getName());
}
}
if (expr instanceof RexLocalRef) {
return translate(program.getExprList().get(((RexLocalRef) expr).getIndex()));
}
if (expr instanceof RexLiteral) {
return Expressions.constant(
((RexLiteral) expr).getValue(), typeFactory.getJavaClass(expr.getType()));
}
if (expr instanceof RexCall) {
final RexCall call = (RexCall) expr;
final SqlOperator operator = call.getOperator();
final ExpressionType expressionType = SQL_TO_LINQ_OPERATOR_MAP.get(operator);
if (expressionType != null) {
switch (operator.getSyntax()) {
case Binary:
return Expressions.makeBinary(
expressionType, translate(call.getOperands()[0]), translate(call.getOperands()[1]));
case Postfix:
case Prefix:
return Expressions.makeUnary(expressionType, translate(call.getOperands()[0]));
default:
throw new RuntimeException("unknown syntax " + operator.getSyntax());
}
}
Method method = SQL_OP_TO_JAVA_METHOD_MAP.get(operator);
if (method != null) {
List<Expression> exprs = translateList(Arrays.asList(call.operands));
return !Modifier.isStatic(method.getModifiers())
? Expressions.call(exprs.get(0), method, exprs.subList(1, exprs.size()))
: Expressions.call(method, exprs);
}
switch (expr.getKind()) {
default:
throw new RuntimeException("cannot translate expression " + expr);
}
}
throw new RuntimeException("cannot translate expression " + expr);
}
public Boolean areColumnsUnique(ProjectRelBase rel, BitSet columns, boolean ignoreNulls) {
// ProjectRel maps a set of rows to a different set;
// Without knowledge of the mapping function(whether it
// preserves uniqueness), it is only safe to derive uniqueness
// info from the child of a project when the mapping is f(a) => a.
//
// Also need to map the input column set to the corresponding child
// references
List<RexNode> projExprs = rel.getProjects();
BitSet childColumns = new BitSet();
for (int bit : BitSets.toIter(columns)) {
RexNode projExpr = projExprs.get(bit);
if (projExpr instanceof RexInputRef) {
childColumns.set(((RexInputRef) projExpr).getIndex());
} else if (projExpr instanceof RexCall && ignoreNulls) {
// If the expression is a cast such that the types are the same
// except for the nullability, then if we're ignoring nulls,
// it doesn't matter whether the underlying column reference
// is nullable. Check that the types are the same by making a
// nullable copy of both types and then comparing them.
RexCall call = (RexCall) projExpr;
if (call.getOperator() != SqlStdOperatorTable.CAST) {
continue;
}
RexNode castOperand = call.getOperands().get(0);
if (!(castOperand instanceof RexInputRef)) {
continue;
}
RelDataTypeFactory typeFactory = rel.getCluster().getTypeFactory();
RelDataType castType = typeFactory.createTypeWithNullability(projExpr.getType(), true);
RelDataType origType = typeFactory.createTypeWithNullability(castOperand.getType(), true);
if (castType.equals(origType)) {
childColumns.set(((RexInputRef) castOperand).getIndex());
}
} else {
// If the expression will not influence uniqueness of the
// projection, then skip it.
continue;
}
}
// If no columns can affect uniqueness, then return unknown
if (childColumns.cardinality() == 0) {
return null;
}
return RelMetadataQuery.areColumnsUnique(rel.getChild(), childColumns, ignoreNulls);
}
// implement CallConvertlet
public void convert(RexCall call) {
// REVIEW jvs 18-Mar-2006: The test for variableSeen
// here and elsewhere precludes predicates like where
// (boolean_col AND (int_col > 10)). Should probably
// support bare boolean columns as predicates with
// coordinate TRUE.
if (variableSeen || (coordinate != null)) {
failed = true;
}
if (failed) {
return;
}
int nOperands = call.getOperands().size();
assert (exprStack.size() >= nOperands);
SargSetExpr expr = factory.newSetExpr(boundInputRef.getType(), setOp);
// Pop the correct number of operands off the stack
// and transfer them to the new set expression.
ListIterator<SargExpr> iter = exprStack.listIterator(exprStack.size() - nOperands);
while (iter.hasNext()) {
expr.addChild(iter.next());
iter.remove();
}
exprStack.add(expr);
}
private void analyzeCall(RexCall call, Constancy callConstancy) {
parentCallTypeStack.add(call.getOperator());
// visit operands, pushing their states onto stack
super.visitCall(call);
// look for NON_CONSTANT operands
int nOperands = call.getOperands().length;
List<Constancy> operandStack = stack.subList(stack.size() - nOperands, stack.size());
for (Constancy operandConstancy : operandStack) {
if (operandConstancy == Constancy.NON_CONSTANT) {
callConstancy = Constancy.NON_CONSTANT;
}
}
// Even if all operands are constant, the call itself may
// be non-deterministic.
if (!call.getOperator().isDeterministic()) {
callConstancy = Constancy.NON_CONSTANT;
} else if (call.getOperator().isDynamicFunction()) {
// We can reduce the call to a constant, but we can't
// cache the plan if the function is dynamic
preparingStmt.disableStatementCaching();
}
// Row operator itself can't be reduced to a literal, but if
// the operands are constants, we still want to reduce those
if ((callConstancy == Constancy.REDUCIBLE_CONSTANT)
&& (call.getOperator() instanceof SqlRowOperator)) {
callConstancy = Constancy.NON_CONSTANT;
}
if (callConstancy == Constancy.NON_CONSTANT) {
// any REDUCIBLE_CONSTANT children are now known to be maximal
// reducible subtrees, so they can be added to the result
// list
for (int iOperand = 0; iOperand < nOperands; ++iOperand) {
Constancy constancy = operandStack.get(iOperand);
if (constancy == Constancy.REDUCIBLE_CONSTANT) {
addResult(call.getOperands()[iOperand]);
}
}
// if this cast expression can't be reduced to a literal,
// then see if we can remove the cast
if (call.getOperator() == SqlStdOperatorTable.castFunc) {
reduceCasts(call);
}
}
// pop operands off of the stack
operandStack.clear();
// pop this parent call operator off the stack
parentCallTypeStack.remove(parentCallTypeStack.size() - 1);
// push constancy result for this call onto stack
stack.add(callConstancy);
}
/**
* 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);
}
// override RexShuttle
public RexNode visitCall(final RexCall call) {
int i = reducibleExps.indexOf(call);
if (i == -1) {
return super.visitCall(call);
}
RexNode replacement = reducedValues.get(i);
if (addCasts.get(i) && (replacement.getType() != call.getType())) {
// Handle change from nullable to NOT NULL by claiming
// that the result is still nullable, even though
// we know it isn't.
//
// Also, we cannot reduce CAST('abc' AS VARCHAR(4)) to 'abc'.
// If we make 'abc' of type VARCHAR(4), we may later encounter
// the same expression in a ProjectRel's digest where it has
// type VARCHAR(3), and that's wrong.
replacement = rexBuilder.makeCast(call.getType(), replacement);
}
return replacement;
}
public Void visitCall(RexCall call) {
CallConvertlet convertlet = convertletMap.get(call.getOperator());
if (convertlet == null) {
failed = true;
return null;
}
// visit operands first
super.visitCall(call);
convertlet.convert(call);
return null;
}
public void onMatch(RelOptRuleCall call) {
FilterRel filter = (FilterRel) call.rels[0];
List<RexNode> expList = new ArrayList<RexNode>(Arrays.asList(filter.getChildExps()));
RexNode newConditionExp;
boolean reduced;
if (reduceExpressions(filter, expList)) {
assert (expList.size() == 1);
newConditionExp = expList.get(0);
reduced = true;
} else {
// No reduction, but let's still test the original
// predicate to see if it was already a constant,
// in which case we don't need any runtime decision
// about filtering.
newConditionExp = filter.getChildExps()[0];
reduced = false;
}
if (newConditionExp.isAlwaysTrue()) {
call.transformTo(filter.getChild());
} else if ((newConditionExp instanceof RexLiteral)
|| RexUtil.isNullLiteral(newConditionExp, true)) {
call.transformTo(new EmptyRel(filter.getCluster(), filter.getRowType()));
} else if (reduced) {
call.transformTo(CalcRel.createFilter(filter.getChild(), expList.get(0)));
} else {
if (newConditionExp instanceof RexCall) {
RexCall rexCall = (RexCall) newConditionExp;
boolean reverse = (rexCall.getOperator() == SqlStdOperatorTable.notOperator);
if (reverse) {
rexCall = (RexCall) rexCall.getOperands()[0];
}
reduceNotNullableFilter(call, filter, rexCall, reverse);
}
return;
}
// New plan is absolutely better than old plan.
call.getPlanner().setImportance(filter, 0.0);
}
private void reduceCasts(RexCall outerCast) {
RexNode[] operands = outerCast.getOperands();
if (operands.length != 1) {
return;
}
RelDataType outerCastType = outerCast.getType();
RelDataType operandType = operands[0].getType();
if (operandType.equals(outerCastType)) {
removableCasts.add(outerCast);
return;
}
// See if the reduction
// CAST((CAST x AS type) AS type NOT NULL)
// -> CAST(x AS type NOT NULL)
// applies. TODO jvs 15-Dec-2008: consider
// similar cases for precision changes.
if (!(operands[0] instanceof RexCall)) {
return;
}
RexCall innerCast = (RexCall) operands[0];
if (innerCast.getOperator() != SqlStdOperatorTable.castFunc) {
return;
}
if (innerCast.getOperands().length != 1) {
return;
}
RelDataTypeFactory typeFactory = preparingStmt.getFarragoTypeFactory();
RelDataType outerTypeNullable = typeFactory.createTypeWithNullability(outerCastType, true);
RelDataType innerTypeNullable = typeFactory.createTypeWithNullability(operandType, true);
if (outerTypeNullable != innerTypeNullable) {
return;
}
if (operandType.isNullable()) {
removableCasts.add(innerCast);
}
}
// implement FarragoOJRexImplementor
public Expression implementFarrago(
FarragoRexToOJTranslator translator, RexCall call, Expression[] operands) {
RelDataType lhsType = call.getType();
RelDataType rhsType = call.operands[0].getType();
Expression rhsExp = operands[0];
SqlTypeName lhsTypeName = lhsType.getSqlTypeName();
if ((lhsTypeName == SqlTypeName.CURSOR) || (lhsTypeName == SqlTypeName.COLUMN_LIST)) {
// Conversion should already have been taken care of outside.
return rhsExp;
}
// NOTE jvs 19-Nov-2008: In some cases (e.g. FRG-273) a cast
// may be illegal at the SQL level, but allowable as part of
// implementation, so don't try to enforce
// SqlTypeUtil.canCastFrom here. Anything which was supposed
// to have been prevented should already have been caught
// by the validator.
CastHelper helper =
new CastHelper(translator, null, call.toString(), lhsType, rhsType, null, rhsExp);
return helper.implement();
}
// implement CallConvertlet
public void convert(RexCall call) {
if (!variableSeen) {
failed = true;
}
SqlOperator op = call.getOperator();
if ((op == SqlStdOperatorTable.isNullOperator)
|| (op == SqlStdOperatorTable.isUnknownOperator)) {
coordinate = factory.getRexBuilder().constantNull();
} else if (op == SqlStdOperatorTable.isTrueOperator) {
coordinate = factory.getRexBuilder().makeLiteral(true);
} else if (op == SqlStdOperatorTable.isFalseOperator) {
coordinate = factory.getRexBuilder().makeLiteral(false);
} else if (coordinate == null) {
failed = true;
}
if (failed) {
return;
}
SargIntervalExpr expr = factory.newIntervalExpr(boundInputRef.getType());
if (boundType == null) {
expr.setPoint(coordinate);
} else {
SargBoundType actualBound = boundType;
if (reverse) {
if (actualBound == SargBoundType.LOWER) {
actualBound = SargBoundType.UPPER;
} else {
actualBound = SargBoundType.LOWER;
}
}
if (actualBound == SargBoundType.LOWER) {
expr.setLower(coordinate, strictness);
} else {
expr.setUpper(coordinate, strictness);
}
}
exprStack.add(expr);
clearLeaf();
}
/** Converts an expression from {@link RexNode} to {@link SqlNode} format. */
SqlNode toSql(RexProgram program, RexNode rex) {
if (rex instanceof RexLocalRef) {
final int index = ((RexLocalRef) rex).getIndex();
return toSql(program, program.getExprList().get(index));
} else if (rex instanceof RexInputRef) {
return field(((RexInputRef) rex).getIndex());
} else if (rex instanceof RexLiteral) {
final RexLiteral literal = (RexLiteral) rex;
switch (literal.getTypeName().getFamily()) {
case CHARACTER:
return SqlLiteral.createCharString((String) literal.getValue2(), POS);
case NUMERIC:
case EXACT_NUMERIC:
return SqlLiteral.createExactNumeric(literal.getValue().toString(), POS);
case APPROXIMATE_NUMERIC:
return SqlLiteral.createApproxNumeric(literal.getValue().toString(), POS);
case BOOLEAN:
return SqlLiteral.createBoolean((Boolean) literal.getValue(), POS);
case DATE:
return SqlLiteral.createDate((Calendar) literal.getValue(), POS);
case TIME:
return SqlLiteral.createTime(
(Calendar) literal.getValue(), literal.getType().getPrecision(), POS);
case TIMESTAMP:
return SqlLiteral.createTimestamp(
(Calendar) literal.getValue(), literal.getType().getPrecision(), POS);
case ANY:
switch (literal.getTypeName()) {
case NULL:
return SqlLiteral.createNull(POS);
// fall through
}
default:
throw new AssertionError(literal + ": " + literal.getTypeName());
}
} else if (rex instanceof RexCall) {
final RexCall call = (RexCall) rex;
final SqlOperator op = call.getOperator();
final List<SqlNode> nodeList = toSql(program, call.getOperands());
if (op == SqlStdOperatorTable.CAST) {
RelDataType type = call.getType();
if (type.getSqlTypeName() == SqlTypeName.VARCHAR
&& dialect.getDatabaseProduct() == SqlDialect.DatabaseProduct.MYSQL) {
// MySQL doesn't have a VARCHAR type, only CHAR.
nodeList.add(
new SqlDataTypeSpec(
new SqlIdentifier("CHAR", POS), type.getPrecision(), -1, null, null, POS));
} else {
nodeList.add(toSql(type));
}
}
if (op == SqlStdOperatorTable.CASE) {
final SqlNode valueNode;
final List<SqlNode> whenList = Expressions.list();
final List<SqlNode> thenList = Expressions.list();
final SqlNode elseNode;
if (nodeList.size() % 2 == 0) {
// switched:
// "case x when v1 then t1 when v2 then t2 ... else e end"
valueNode = nodeList.get(0);
for (int i = 1; i < nodeList.size() - 1; i += 2) {
whenList.add(nodeList.get(i));
thenList.add(nodeList.get(i + 1));
}
} else {
// other: "case when w1 then t1 when w2 then t2 ... else e end"
valueNode = null;
for (int i = 0; i < nodeList.size() - 1; i += 2) {
whenList.add(nodeList.get(i));
thenList.add(nodeList.get(i + 1));
}
}
elseNode = nodeList.get(nodeList.size() - 1);
return op.createCall(
POS,
valueNode,
new SqlNodeList(whenList, POS),
new SqlNodeList(thenList, POS),
elseNode);
}
if (op instanceof SqlBinaryOperator && nodeList.size() > 2) {
// In RexNode trees, OR and AND have any number of children;
// SqlCall requires exactly 2. So, convert to a left-deep binary tree.
return createLeftCall(op, nodeList);
}
return op.createCall(new SqlNodeList(nodeList, POS));
} else {
throw new AssertionError(rex);
}
}
@Override
public TupleFilter visitCall(RexCall call) {
TupleFilter filter = null;
SqlOperator op = call.getOperator();
switch (op.getKind()) {
case AND:
filter = new LogicalTupleFilter(FilterOperatorEnum.AND);
break;
case OR:
filter = new LogicalTupleFilter(FilterOperatorEnum.OR);
break;
case NOT:
filter = new LogicalTupleFilter(FilterOperatorEnum.NOT);
break;
case EQUALS:
filter = new CompareTupleFilter(FilterOperatorEnum.EQ);
break;
case GREATER_THAN:
filter = new CompareTupleFilter(FilterOperatorEnum.GT);
break;
case LESS_THAN:
filter = new CompareTupleFilter(FilterOperatorEnum.LT);
break;
case GREATER_THAN_OR_EQUAL:
filter = new CompareTupleFilter(FilterOperatorEnum.GTE);
break;
case LESS_THAN_OR_EQUAL:
filter = new CompareTupleFilter(FilterOperatorEnum.LTE);
break;
case NOT_EQUALS:
filter = new CompareTupleFilter(FilterOperatorEnum.NEQ);
break;
case IS_NULL:
filter = new CompareTupleFilter(FilterOperatorEnum.ISNULL);
break;
case IS_NOT_NULL:
filter = new CompareTupleFilter(FilterOperatorEnum.ISNOTNULL);
break;
case CAST:
case REINTERPRET:
// NOTE: use child directly
break;
case CASE:
filter = new CaseTupleFilter();
break;
case OTHER:
if (op.getName().equalsIgnoreCase("extract_date")) {
filter = new ExtractTupleFilter(FilterOperatorEnum.EXTRACT);
} else {
throw new UnsupportedOperationException(op.getName());
}
break;
default:
throw new UnsupportedOperationException(op.getName());
}
for (RexNode operand : call.operands) {
TupleFilter childFilter = operand.accept(this);
if (filter == null) {
filter = childFilter;
} else {
filter.addChild(childFilter);
}
}
if (op.getKind() == SqlKind.OR) {
CompareTupleFilter inFilter = mergeToInClause(filter);
if (inFilter != null) {
filter = inFilter;
}
}
return filter;
}
/**
* Reduces a list of expressions.
*
* @param rel Relational expression
* @param expList List of expressions, modified in place
* @return whether reduction found something to change, and succeeded
*/
static boolean reduceExpressions(RelNode rel, List<RexNode> expList) {
RexBuilder rexBuilder = rel.getCluster().getRexBuilder();
// Find reducible expressions.
FarragoSessionPlanner planner = (FarragoSessionPlanner) rel.getCluster().getPlanner();
FarragoSessionPreparingStmt preparingStmt = planner.getPreparingStmt();
List<RexNode> constExps = new ArrayList<RexNode>();
List<Boolean> addCasts = new ArrayList<Boolean>();
List<RexNode> removableCasts = new ArrayList<RexNode>();
findReducibleExps(preparingStmt, expList, constExps, addCasts, removableCasts);
if (constExps.isEmpty() && removableCasts.isEmpty()) {
return false;
}
// Remove redundant casts before reducing constant expressions.
// If the argument to the redundant cast is a reducible constant,
// reducing that argument to a constant first will result in not being
// able to locate the original cast expression.
if (!removableCasts.isEmpty()) {
List<RexNode> reducedExprs = new ArrayList<RexNode>();
List<Boolean> noCasts = new ArrayList<Boolean>();
for (RexNode exp : removableCasts) {
RexCall call = (RexCall) exp;
reducedExprs.add(call.getOperands()[0]);
noCasts.add(false);
}
RexReplacer replacer = new RexReplacer(rexBuilder, removableCasts, reducedExprs, noCasts);
replacer.apply(expList);
}
if (constExps.isEmpty()) {
return true;
}
// Compute the values they reduce to.
List<RexNode> reducedValues = new ArrayList<RexNode>();
ReentrantValuesStmt reentrantStmt =
new ReentrantValuesStmt(
preparingStmt.getRootStmtContext(), rexBuilder, constExps, reducedValues);
FarragoSession session = getSession(rel);
reentrantStmt.execute(session, true);
if (reentrantStmt.failed) {
return false;
}
// For ProjectRel, we have to be sure to preserve the result
// types, so always cast regardless of the expression type.
// For other RelNodes like FilterRel, in general, this isn't necessary,
// and the presence of casts could hinder other rules such as sarg
// analysis, which require bare literals. But there are special cases,
// like when the expression is a UDR argument, that need to be
// handled as special cases.
if (rel instanceof ProjectRel) {
for (int i = 0; i < reducedValues.size(); i++) {
addCasts.set(i, true);
}
}
RexReplacer replacer = new RexReplacer(rexBuilder, constExps, reducedValues, addCasts);
replacer.apply(expList);
return true;
}
