org.apache.calcite.piglet.PigRelOpVisitor Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of calcite-piglet Show documentation
Show all versions of calcite-piglet Show documentation
Pig-like language built on top of Calcite algebra
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.calcite.piglet;
import org.apache.calcite.plan.RelOptTable;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.core.JoinRelType;
import org.apache.calcite.rel.logical.LogicalCorrelate;
import org.apache.calcite.rel.logical.LogicalJoin;
import org.apache.calcite.rel.logical.LogicalProject;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeField;
import org.apache.calcite.rex.RexFieldCollation;
import org.apache.calcite.rex.RexInputRef;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.rex.RexWindowBound;
import org.apache.calcite.sql.SqlAggFunction;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.sql.SqlWindow;
import org.apache.calcite.sql.fun.SqlStdOperatorTable;
import org.apache.calcite.sql.parser.SqlParserPos;
import org.apache.calcite.sql.type.SqlTypeName;
import org.apache.calcite.tools.RelBuilder;
import org.apache.calcite.util.ImmutableBitSet;
import org.apache.pig.builtin.CubeDimensions;
import org.apache.pig.builtin.RollupDimensions;
import org.apache.pig.impl.logicalLayer.FrontendException;
import org.apache.pig.impl.util.LinkedMultiMap;
import org.apache.pig.impl.util.MultiMap;
import org.apache.pig.newplan.Operator;
import org.apache.pig.newplan.OperatorPlan;
import org.apache.pig.newplan.PlanWalker;
import org.apache.pig.newplan.logical.expression.LogicalExpressionPlan;
import org.apache.pig.newplan.logical.expression.UserFuncExpression;
import org.apache.pig.newplan.logical.relational.LOCogroup;
import org.apache.pig.newplan.logical.relational.LOCross;
import org.apache.pig.newplan.logical.relational.LOCube;
import org.apache.pig.newplan.logical.relational.LODistinct;
import org.apache.pig.newplan.logical.relational.LOFilter;
import org.apache.pig.newplan.logical.relational.LOForEach;
import org.apache.pig.newplan.logical.relational.LOGenerate;
import org.apache.pig.newplan.logical.relational.LOInnerLoad;
import org.apache.pig.newplan.logical.relational.LOJoin;
import org.apache.pig.newplan.logical.relational.LOLimit;
import org.apache.pig.newplan.logical.relational.LOLoad;
import org.apache.pig.newplan.logical.relational.LONative;
import org.apache.pig.newplan.logical.relational.LORank;
import org.apache.pig.newplan.logical.relational.LOSort;
import org.apache.pig.newplan.logical.relational.LOSplit;
import org.apache.pig.newplan.logical.relational.LOSplitOutput;
import org.apache.pig.newplan.logical.relational.LOStore;
import org.apache.pig.newplan.logical.relational.LOStream;
import org.apache.pig.newplan.logical.relational.LOUnion;
import org.apache.pig.newplan.logical.relational.LogicalPlan;
import org.apache.pig.newplan.logical.relational.LogicalRelationalOperator;
import org.apache.pig.newplan.logical.relational.LogicalSchema;
import com.google.common.collect.ImmutableList;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
/**
* Visits Pig logical operators and converts them into corresponding relational
* algebra plans.
*/
class PigRelOpVisitor extends PigRelOpWalker.PlanPreVisitor {
private static final String RANK_PREFIX = "rank_";
// The relational algebra builder customized for Pig
protected final PigRelBuilder builder;
private Operator currentRoot;
/**
* Type of Pig groups
*/
private enum GroupType {
CUBE,
ROLLUP,
REGULAR
}
/**
* Creates a PigRelOpVisitor.
*
* @param plan Pig logical plan
* @param walker The walker over Pig logical plan
* @param builder Relational algebra builder
* @throws FrontendException Exception during processing Pig operators
*/
PigRelOpVisitor(OperatorPlan plan, PlanWalker walker, PigRelBuilder builder)
throws FrontendException {
super(plan, walker);
if (!(walker instanceof PigRelOpWalker)) {
throw new FrontendException("Expected PigRelOpWalker", 2223);
}
this.builder = builder;
this.currentRoot = null;
}
Operator getCurrentRoot() {
return currentRoot;
}
/**
* Translates the given pig logical plan into a list of relational algebra plans.
*
* @return The list of roots of translated plans, each corresponding to a sink
* operator in the Pig plan
* @throws FrontendException Exception during processing Pig operators
*/
List translate() throws FrontendException {
List relNodes = new ArrayList<>();
for (Operator pigOp : plan.getSinks()) {
currentRoot = pigOp;
currentWalker.walk(this);
if (!(pigOp instanceof LOStore)) {
relNodes.add(builder.build());
}
}
return relNodes;
}
@Override public void visit(LOLoad load) throws FrontendException {
// Two types of tables to load:
// 1. LOAD '[schemaName.]tableName': load table from database catalog
// 2. LOAD '/path/to/tableName': load from a file
String fullName = load.getSchemaFile();
if (fullName.contains("file://")) {
// load from database catalog. Pig will see it as a file in the working directory
fullName = Paths.get(load.getSchemaFile()).getFileName().toString();
}
String[] tableNames;
if (fullName.startsWith("/")) {
// load from file
tableNames = new String[1];
tableNames[0] = fullName;
} else {
// load from catalog
tableNames = fullName.split("\\.");
}
final LogicalSchema pigSchema = load.getSchema();
final RelOptTable pigRelOptTable;
if (pigSchema == null) {
pigRelOptTable = null;
} else {
// If Pig schema is provided in the load command, convert it into
// relational row type
final RelDataType rowType = PigTypes.convertSchema(pigSchema);
pigRelOptTable = PigTable.createRelOptTable(builder.getRelOptSchema(),
rowType, Arrays.asList(tableNames));
}
builder.scan(pigRelOptTable, tableNames);
builder.register(load);
}
@Override public void visit(LOFilter filter) throws FrontendException {
final RexNode relExFilter = PigRelExVisitor.translatePigEx(builder, filter.getFilterPlan());
builder.filter(relExFilter);
builder.register(filter);
}
@Override public void visit(LOForEach foreach) throws FrontendException {
// Use an inner visitor to translate Pig inner plan into a relational plan
// See @PigRelOpInnerVisitor for details.
PigRelOpWalker innerWalker = new PigRelOpWalker(foreach.getInnerPlan());
PigRelOpInnerVisitor innerVisitor =
new PigRelOpInnerVisitor(foreach.getInnerPlan(), innerWalker, builder);
RelNode root = innerVisitor.translate().get(0);
builder.push(root);
builder.register(foreach);
}
@Override public void visit(LOCogroup loCogroup) throws FrontendException {
// Pig parser already converted CUBE operator into a set of operators, including LOCogroup.
// Thus this method handles all GROUP/COGROUP/CUBE commands
final GroupType groupType = getGroupType(loCogroup);
if (groupType == GroupType.REGULAR) {
processRegularGroup(loCogroup);
} else { // for CUBE and ROLLUP
processCube(groupType, loCogroup);
}
// Finally project the group and aggregate fields. Note that if group consists of multiple
// group keys, we do grouping using multiple keys and then convert these group keys into
// a single composite group key (with tuple/struct type) in this step.
// The other option is to create the composite group key first and do grouping on this
// composite key. But this option is less friendly the relational algebra, which flat
// types are more common.
projectGroup(loCogroup.getExpressionPlans().get(0).size());
builder.register(loCogroup);
}
/**
* Projects group key with 'group' alias so that upstream operator can refer to, along
* with other aggregate columns. If group consists of multiple group keys, construct
* a composite tuple/struct type to make it compatible with PIG group semantic.
*
* @param groupCount Number of group keys.
*/
private void projectGroup(int groupCount) {
final List inputFields = builder.peek().getRowType().getFieldList();
RexNode groupRex;
// First construct the group field
if (groupCount == 1) {
// Single group key, just project it out directly
groupRex = builder.field(0);
} else {
// Otherwise, build a struct for all group keys use SQL ROW operator
List fieldNames = new ArrayList<>();
List fieldTypes = new ArrayList<>();
List fieldRexes = new ArrayList<>();
for (int j = 0; j < groupCount; j++) {
fieldTypes.add(inputFields.get(j).getType());
fieldNames.add(inputFields.get(j).getName());
fieldRexes.add(builder.field(j));
}
RelDataType groupDataType =
PigTypes.TYPE_FACTORY.createStructType(fieldTypes, fieldNames);
groupRex = builder.getRexBuilder().makeCall(
groupDataType, SqlStdOperatorTable.ROW, fieldRexes);
}
List outputFields = new ArrayList<>();
List outputNames = new ArrayList<>();
// Project group field first
outputFields.add(groupRex);
outputNames.add("group");
// Then all other aggregate fields
for (int i = groupCount; i < inputFields.size(); i++) {
outputFields.add(builder.field(i));
outputNames.add(inputFields.get(i).getName());
}
builder.project(outputFields, outputNames, true);
}
/**
* Processes regular a group/group.
*
* @param loCogroup Pig logical group operator
* @throws FrontendException Exception during processing Pig operators
*/
private void processRegularGroup(LOCogroup loCogroup) throws FrontendException {
final List groupKeys = new ArrayList<>();
final int numRels = loCogroup.getExpressionPlans().size();
// Project out the group keys and the whole row, which will be aggregated with
// COLLECT operator later.
preprocessCogroup(loCogroup, false);
// Build the group key
for (Integer key : loCogroup.getExpressionPlans().keySet()) {
final int groupCount = loCogroup.getExpressionPlans().get(key).size();
final List relKeys = new ArrayList<>();
for (int i = 0; i < groupCount; i++) {
relKeys.add(builder.field(numRels - key, 0, i));
}
groupKeys.add(builder.groupKey(relKeys));
}
// The do COLLECT aggregate.
builder.cogroup(groupKeys);
}
/**
* Processes a CUBE/ROLLUP group type.
*
* @param groupType type of the group, either ROLLUP or CUBE
* @param loCogroup Pig logical group operator
* @throws FrontendException Exception during processing Pig operator
*/
private void processCube(GroupType groupType, LOCogroup loCogroup)
throws FrontendException {
assert loCogroup.getExpressionPlans().size() == 1;
// First adjust the top rel in the builder, which will be served as input rel for
// the CUBE COGROUP operator because Pig already convert LOCube into
// a ForEach (to project out the group set using @CubeDimensions or @RollupDimension UDFs)
// and a @LOCogroup. We dont need to use these UDFs to generate the groupset.
// So we need to undo the effect of translate this ForEach int relational
// algebra nodes before.
adjustCubeInput();
// Project out the group keys and the whole row, which will be aggregated with
// COLLECT operator later.
preprocessCogroup(loCogroup, true);
// Generate the group set for the corresponding group type.
ImmutableList.Builder groupsetBuilder =
new ImmutableList.Builder<>();
List keyIndexs = new ArrayList<>();
groupsetBuilder.add(ImmutableBitSet.of(keyIndexs));
int groupCount = loCogroup.getExpressionPlans().get(0).size();
for (int i = groupCount - 1; i >= 0; i--) {
keyIndexs.add(i);
groupsetBuilder.add(ImmutableBitSet.of(keyIndexs));
}
final ImmutableBitSet groupSet = ImmutableBitSet.of(keyIndexs);
final ImmutableList groupSets =
(groupType == GroupType.CUBE)
? ImmutableList.copyOf(groupSet.powerSet()) : groupsetBuilder.build();
RelBuilder.GroupKey groupKey = builder.groupKey(groupSet,
(Iterable) groupSets);
// Finally, do COLLECT aggregate.
builder.cogroup(ImmutableList.of(groupKey));
}
/**
* Adjusts the rel input for Pig Cube operator.
*/
private void adjustCubeInput() {
RelNode project1 = builder.peek();
assert project1 instanceof LogicalProject;
RelNode correl = ((LogicalProject) project1).getInput();
assert correl instanceof LogicalCorrelate;
RelNode project2 = ((LogicalCorrelate) correl).getLeft();
assert project2 instanceof LogicalProject;
builder.replaceTop(((LogicalProject) project2).getInput());
}
/**
* Projects out group key and the row for each relation
*
* @param loCogroup Pig logical group operator
* @throws FrontendException Exception during processing Pig operator
*/
private void preprocessCogroup(LOCogroup loCogroup, boolean isCubeRollup)
throws FrontendException {
final int numRels = loCogroup.getExpressionPlans().size();
// Pull out all cogrouped relations from the builder
List inputRels = new ArrayList<>();
for (int i = 0; i < numRels; i++) {
inputRels.add(0, builder.build());
}
// Then adding back with the corresponding projection
for (int i = 0; i < numRels; i++) {
final RelNode originalRel = inputRels.get(i);
builder.push(originalRel);
final Collection pigGroupKeys =
loCogroup.getExpressionPlans().get(i);
List fieldRels = new ArrayList<>();
for (LogicalExpressionPlan pigKey : pigGroupKeys) {
fieldRels.add(PigRelExVisitor.translatePigEx(builder, pigKey));
}
final RexNode row = builder.getRexBuilder().makeCall(getGroupRowType(fieldRels, isCubeRollup),
SqlStdOperatorTable.ROW, getGroupRowOperands(fieldRels, isCubeRollup));
fieldRels.add(row);
builder.project(fieldRels);
builder.updateAlias(builder.getPig(originalRel), builder.getAlias(originalRel), false);
}
}
// Gets row type for the group column
private RelDataType getGroupRowType(List groupFields, boolean isCubeRollup) {
if (isCubeRollup) {
final List rowFields = builder.peek().getRowType().getFieldList();
final List fieldNames = new ArrayList<>();
final List fieldTypes = new ArrayList<>();
final List groupColIndexes = new ArrayList<>();
// First copy fields of grouping columns
for (RexNode rex : groupFields) {
assert rex instanceof RexInputRef;
int colIndex = ((RexInputRef) rex).getIndex();
groupColIndexes.add(colIndex);
fieldNames.add(rowFields.get(colIndex).getName());
fieldTypes.add(rowFields.get(colIndex).getType());
}
// Then copy the remaining fields from the parent rel
for (int i = 0; i < rowFields.size(); i++) {
if (!groupColIndexes.contains(i)) {
fieldNames.add(rowFields.get(i).getName());
fieldTypes.add(rowFields.get(i).getType());
}
}
return PigTypes.TYPE_FACTORY.createStructType(fieldTypes, fieldNames);
}
return builder.peek().getRowType();
}
/** Gets the operands for the ROW operator to construct the group column. */
private List getGroupRowOperands(List fieldRels,
boolean isCubeRollup) {
final List rowFields = builder.fields();
if (isCubeRollup) {
// Add group by columns first
List cubeRowFields = new ArrayList<>(fieldRels);
// Then and remaining columns
for (RexNode field : rowFields) {
if (!cubeRowFields.contains(field)) {
cubeRowFields.add(field);
}
}
return cubeRowFields;
}
return rowFields;
}
/**
* Checks the group type of a group.
*
* @param pigGroup Pig logical group operator
* @return The group type, either CUBE, ROLLUP, or REGULAR
*/
private static GroupType getGroupType(LOCogroup pigGroup) {
if (pigGroup.getInputs((LogicalPlan) pigGroup.getPlan()).size() == 1) {
final Operator input = pigGroup.getInputs((LogicalPlan) pigGroup.getPlan()).get(0);
if (input instanceof LOForEach) {
final LOForEach foreach = (LOForEach) input;
if (foreach.getInnerPlan().getSinks().size() == 1) {
final LOGenerate generate = (LOGenerate) foreach.getInnerPlan().getSinks().get(0);
final List projectList = generate.getOutputPlans();
if (projectList.size() > 1) {
final LogicalExpressionPlan exPlan = projectList.get(0);
if (exPlan.getSources().size() == 1
&& exPlan.getSources().get(0) instanceof UserFuncExpression) {
final UserFuncExpression func = (UserFuncExpression) exPlan.getSources().get(0);
if (func.getFuncSpec().getClassName().equals(CubeDimensions.class.getName())) {
return GroupType.CUBE;
}
if (func.getFuncSpec().getClassName().equals(RollupDimensions.class.getName())) {
return GroupType.ROLLUP;
}
}
}
}
}
}
return GroupType.REGULAR;
}
@Override public void visit(LOLimit loLimit) throws FrontendException {
builder.limit(0, (int) loLimit.getLimit());
builder.register(loLimit);
}
@Override public void visit(LOSort loSort) throws FrontendException {
// TODO Hanlde custom sortFunc from Pig???
final int limit = (int) loSort.getLimit();
List relSortCols = new ArrayList<>();
if (loSort.isStar()) {
// Sort using all columns
RelNode top = builder.peek();
for (RelDataTypeField field : top.getRowType().getFieldList()) {
relSortCols.add(builder.field(field.getIndex()));
}
} else {
// Sort using specific columns
assert loSort.getSortColPlans().size() == loSort.getAscendingCols().size();
for (int i = 0; i < loSort.getSortColPlans().size(); i++) {
RexNode sortColsNoDirection =
PigRelExVisitor.translatePigEx(builder, loSort.getSortColPlans().get(i));
// Add sort directions
if (!loSort.getAscendingCols().get(i)) {
relSortCols.add(builder.desc(sortColsNoDirection));
} else {
relSortCols.add(sortColsNoDirection);
}
}
}
builder.sortLimit(-1, limit, relSortCols);
builder.register(loSort);
}
@Override public void visit(LOJoin join) throws FrontendException {
joinInternal(join.getExpressionPlans(), join.getInnerFlags());
LogicalJoin joinRel = (LogicalJoin) builder.peek();
Set duplicateNames = new HashSet<>(joinRel.getLeft().getRowType().getFieldNames());
duplicateNames.retainAll(joinRel.getRight().getRowType().getFieldNames());
if (!duplicateNames.isEmpty()) {
final List fieldNames = new ArrayList<>();
final List fields = new ArrayList<>();
for (RelDataTypeField leftField : joinRel.getLeft().getRowType().getFieldList()) {
fieldNames.add(builder.getAlias(joinRel.getLeft()) + "::" + leftField.getName());
fields.add(builder.field(leftField.getIndex()));
}
int leftCount = joinRel.getLeft().getRowType().getFieldList().size();
for (RelDataTypeField rightField : joinRel.getRight().getRowType().getFieldList()) {
fieldNames.add(builder.getAlias(joinRel.getRight()) + "::" + rightField.getName());
fields.add(builder.field(rightField.getIndex() + leftCount));
}
builder.project(fields, fieldNames);
}
builder.register(join);
}
@Override public void visit(LOCross loCross) throws FrontendException {
final int numInputs = loCross.getInputs().size();
MultiMap joinPlans = new LinkedMultiMap<>();
boolean[] innerFlags = new boolean[numInputs];
for (int i = 0; i < numInputs; i++) {
// Adding empty join keys
joinPlans.put(i, new LinkedList<>());
innerFlags[i] = true;
}
joinInternal(joinPlans, innerFlags);
builder.register(loCross);
}
/**
* Joins a list of relations (previously pushed into the builder).
*
* @param joinPlans Join keys
* @param innerFlags Join type
* @throws FrontendException Exception during processing Pig operator
*/
private void joinInternal(MultiMap joinPlans,
boolean[] innerFlags) throws FrontendException {
final int numRels = joinPlans.size();
// Pull out all joined relations from the builder
List joinRels = new ArrayList<>();
for (int i = 0; i < numRels; i++) {
joinRels.add(0, builder.build());
}
// Then join each pair from left to right
for (int i = 0; i < numRels; i++) {
builder.push(joinRels.get(i));
if (i == 0) {
continue;
}
List predicates = new ArrayList<>();
List leftJoinExprs = joinPlans.get(i - 1);
List rightJoinExprs = joinPlans.get(i);
assert leftJoinExprs.size() == rightJoinExprs.size();
for (int j = 0; j < leftJoinExprs.size(); j++) {
RexNode leftRelExpr =
PigRelExVisitor.translatePigEx(builder, leftJoinExprs.get(j), 2, 0);
RexNode rightRelExpr =
PigRelExVisitor.translatePigEx(builder, rightJoinExprs.get(j), 2, 1);
predicates.add(builder.equals(leftRelExpr, rightRelExpr));
}
builder.join(getJoinType(innerFlags[i - 1], innerFlags[i]), builder.and(predicates));
}
}
/**
* Decides the join type from the inner types of both relation.
*
* @param leftInner true if the left requires inner
* @param rightInner true if the right requires inner
* @return The join type, either INNER, LEFT, RIGHT, or FULL
*/
private static JoinRelType getJoinType(boolean leftInner, boolean rightInner) {
if (leftInner && rightInner) {
return JoinRelType.INNER;
} else if (leftInner) {
return JoinRelType.LEFT;
} else if (rightInner) {
return JoinRelType.RIGHT;
} else {
return JoinRelType.FULL;
}
}
@Override public void visit(LOUnion loUnion) throws FrontendException {
// The tricky thing to translate union are the input schemas. Relational algebra does not
// support UNION of input with different schemas, so we need to make sure to have inputs
// with same schema first.
LogicalSchema unionSchema = loUnion.getSchema();
if (unionSchema == null) {
throw new IllegalArgumentException("UNION on incompatible types is not supported. "
+ "Please consider using ONSCHEMA option");
}
// First get the shared schema
int numInputs = loUnion.getInputs().size();
RelDataType unionRelType = PigTypes.convertSchema(unionSchema);
// Then using projections to adjust input relations with the shared schema
List adjustedInputs = new ArrayList<>();
for (int i = 0; i < numInputs; i++) {
adjustedInputs.add(builder.project(builder.build(), unionRelType));
}
// Push the adjusted input back to the builder to do union
for (int i = numInputs - 1; i >= 0; i--) {
builder.push(adjustedInputs.get(i));
}
// Finally do union
builder.union(true, numInputs);
builder.register(loUnion);
}
@Override public void visit(LODistinct loDistinct) throws FrontendException {
// Straightforward, just build distinct on the top relation
builder.distinct();
builder.register(loDistinct);
}
@Override public void visit(LOCube cube) throws FrontendException {
// Invalid to get here
throw new FrontendException("Cube should be translated into group by Pig parser", 10000);
}
@Override public void visit(LOInnerLoad load) throws FrontendException {
// InnerLoad should be handled by @PigRelOpInnerVisitor
throw new FrontendException("Not implemented", 10000);
}
@Override public void visit(LOSplit loSplit) throws FrontendException {
builder.register(loSplit);
}
@Override public void visit(LOSplitOutput loSplitOutput) throws FrontendException {
final RexNode relExFilter =
PigRelExVisitor.translatePigEx(builder, loSplitOutput.getFilterPlan());
builder.filter(relExFilter);
builder.register(loSplitOutput);
}
@Override public void visit(LOStore store) throws FrontendException {
builder.store(store.getAlias());
}
@Override public void visit(LOGenerate gen) throws FrontendException {
// LOGenerate should be handled by @PigRelOpInnerVisitor
throw new FrontendException("Not implemented", 10000);
}
@Override public void visit(LORank loRank) throws FrontendException {
// First build the rank field using window function with information from loRank
final RexNode rankField = buildRankField(loRank);
// Then project out the rank field along with all other fields
final RelDataType inputRowType = builder.peek().getRowType();
List projectedFields = new ArrayList<>();
List fieldNames = new ArrayList<>();
projectedFields.add(rankField);
fieldNames.add(RANK_PREFIX + loRank.getAlias()); // alias of the rank field
for (int i = 0; i < inputRowType.getFieldCount(); i++) {
projectedFields.add(builder.field(i));
fieldNames.add(inputRowType.getFieldNames().get(i));
}
// Finally do project
builder.project(projectedFields, fieldNames);
builder.register(loRank);
}
/**
* Builds a window function for {@link LORank}.
*
* @param loRank Pig logical rank operator
* @return The window function
* @throws FrontendException Exception during processing Pig operator
*/
private RexNode buildRankField(LORank loRank) throws FrontendException {
// Aggregate function is either RANK or DENSE_RANK
SqlAggFunction rank =
loRank.isDenseRank() ? SqlStdOperatorTable.DENSE_RANK : SqlStdOperatorTable.RANK;
// Build the order keys
List orderNodes = new ArrayList<>();
for (int i = 0; i < loRank.getRankColPlans().size(); i++) {
RexNode orderNode =
PigRelExVisitor.translatePigEx(builder, loRank.getRankColPlans().get(i));
Set flags = new HashSet<>();
if (!loRank.getAscendingCol().get(i)) {
flags.add(SqlKind.DESCENDING);
}
orderNodes.add(new RexFieldCollation(orderNode, flags));
}
return builder.getRexBuilder().makeOver(
PigTypes.TYPE_FACTORY.createSqlType(SqlTypeName.BIGINT), // Return type
rank, // Aggregate function
Collections.emptyList(), // Operands for the aggregate function, empty here
Collections.emptyList(), // No partition keys
ImmutableList.copyOf(orderNodes), // order keys
RexWindowBound.create(
SqlWindow.createUnboundedPreceding(SqlParserPos.ZERO),
null), // window with unbounded lower
RexWindowBound.create(
SqlWindow.createCurrentRow(SqlParserPos.ZERO),
null), // till current
false, // Range-based
true, // allow partial
false, // not return null when count is zero
false, // no distinct
false);
}
@Override public void visit(LOStream loStream) throws FrontendException {
throw new FrontendException("Not implemented", 10000);
}
@Override public void visit(LONative nativeMR) throws FrontendException {
throw new FrontendException("Not implemented", 10000);
}
@Override public boolean preVisit(LogicalRelationalOperator root) {
return builder.checkMap(root);
}
}