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* Licensed to the Apache Software Foundation (ASF) under one
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* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
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package org.apache.lens.cube.parse.join;
import static org.apache.lens.cube.parse.HQLParser.*;
import java.util.*;
import org.apache.lens.cube.metadata.join.TableRelationship;
import org.apache.lens.cube.parse.*;
import org.apache.lens.server.api.error.LensException;
import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.hive.ql.parse.ASTNode;
import org.apache.hadoop.hive.ql.parse.HiveParser;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
/**
* Join context related to Bridge tables
*/
@Slf4j
public class BridgeTableJoinContext {
private final String bridgeTableFieldAggr;
private final String arrayFilter;
private final CubeQueryContext cubeql;
private final DimHQLContext sc;
private final boolean doFlatteningEarly;
private boolean initedBridgeClauses = false;
private final StringBuilder bridgeSelectClause = new StringBuilder();
private final StringBuilder bridgeFromClause = new StringBuilder();
private final StringBuilder bridgeFilterClause = new StringBuilder();
private final StringBuilder bridgeJoinClause = new StringBuilder();
private final StringBuilder bridgeGroupbyClause = new StringBuilder();
public BridgeTableJoinContext(CubeQueryContext cubeql, DimHQLContext sc,
String bridgeTableFieldAggr, String arrayFilter, boolean doFlatteningEarly) {
this.cubeql = cubeql;
this.sc = sc;
this.bridgeTableFieldAggr = bridgeTableFieldAggr;
this.arrayFilter = arrayFilter;
this.doFlatteningEarly = doFlatteningEarly;
}
public void resetContext() {
initedBridgeClauses = false;
bridgeSelectClause.setLength(0);
bridgeFromClause.setLength(0);
bridgeFilterClause.setLength(0);
bridgeJoinClause.setLength(0);
bridgeGroupbyClause.setLength(0);
}
public void initBridgeClauses(TableRelationship rel, String fromAlias, String toAlias, CandidateDim toTable, String
userFilter,
String storageFilter) {
// we just found a bridge table in the path we need to initialize the clauses for subquery required for
// aggregating fields of bridge table
// initialize select clause with join key
bridgeSelectClause.append(" (select ").append(toAlias).append(".").append(rel.getToColumn()).append(" as ")
.append(rel.getToColumn());
// group by join key
bridgeGroupbyClause.append(" group by ").append(toAlias).append(".").append(rel.getToColumn());
// from clause with bridge table
bridgeFromClause.append(" from ").append(toTable.getStorageString(toAlias));
// we need to initialize filter clause with user filter clause or storage filter if applicable
if (StringUtils.isNotBlank(userFilter)) {
bridgeFilterClause.append(userFilter);
}
if (StringUtils.isNotBlank(storageFilter)) {
if (StringUtils.isNotBlank(bridgeFilterClause.toString())) {
bridgeFilterClause.append(" and ");
}
bridgeFilterClause.append(storageFilter);
}
// initialize final join clause
bridgeJoinClause.append(" on ").append(fromAlias).append(".")
.append(rel.getFromColumn()).append(" = ").append("%s")
.append(".").append(rel.getToColumn());
initedBridgeClauses = true;
}
// if any relation has bridge table, the clause becomes the following :
// join (" select " + joinkey + " aggr over fields from bridge table + from bridgeTable + [where user/storage
// filters] + groupby joinkey) on joincond"
// Or
// " join (select " + joinkey + " aggr over fields from table reached through bridge table + from bridge table
// join on join condition + [and user/storage filters] + groupby joinkey) on joincond
public void updateBridgeClause(TableRelationship rel, String fromAlias, String toAlias, CandidateDim toTable,
String userFilter, String storageFilter) {
if (!initedBridgeClauses) {
initBridgeClauses(rel, fromAlias, toAlias, toTable, userFilter, storageFilter);
} else {
addAnotherJoinClause(rel, fromAlias, toAlias, toTable, userFilter, storageFilter);
}
}
public void addAnotherJoinClause(TableRelationship rel, String fromAlias, String toAlias, CandidateDim toTable,
String userFilter, String storageFilter) {
// if bridge clauses are already inited, this is a next table getting joined with bridge table
// we will append a simple join clause
bridgeFromClause.append(" join ");
bridgeFromClause.append(toTable.getStorageString(toAlias));
bridgeFromClause.append(" on ").append(fromAlias).append(".")
.append(rel.getFromColumn()).append(" = ").append(toAlias)
.append(".").append(rel.getToColumn());
if (StringUtils.isNotBlank(userFilter)) {
bridgeFromClause.append(" and ").append(userFilter);
}
if (StringUtils.isNotBlank(storageFilter)) {
bridgeFromClause.append(" and ").append(storageFilter);
}
}
public String generateJoinClause(String joinTypeStr, String toAlias) throws LensException {
StringBuilder clause = new StringBuilder(joinTypeStr);
clause.append(" join ");
clause.append(bridgeSelectClause.toString());
// iterate over all select expressions and add them for select clause if do_flattening_early is disabled
if (!doFlatteningEarly) {
BridgeTableSelectCtx selectCtx = new BridgeTableSelectCtx(bridgeTableFieldAggr, arrayFilter, toAlias);
selectCtx.processSelectAST(sc.getQueryAst().getSelectAST());
selectCtx.processWhereClauses(sc);
selectCtx.processGroupbyAST(sc.getQueryAst().getGroupByAST());
selectCtx.processOrderbyAST(sc.getQueryAst().getOrderByAST());
clause.append(",").append(StringUtils.join(selectCtx.getSelectedBridgeExprs(), ","));
} else {
for (String col : cubeql.getTblAliasToColumns().get(toAlias)) {
clause.append(",").append(bridgeTableFieldAggr).append("(").append(toAlias)
.append(".").append(col)
.append(")")
.append(" as ").append(col);
}
}
String bridgeFrom = bridgeFromClause.toString();
clause.append(bridgeFrom);
String bridgeFilter = bridgeFilterClause.toString();
if (StringUtils.isNotBlank(bridgeFilter)) {
if (bridgeFrom.contains(" join ")) {
clause.append(" and ");
} else {
clause.append(" where ");
}
clause.append(bridgeFilter);
}
clause.append(bridgeGroupbyClause.toString());
clause.append(") ").append(toAlias);
clause.append(String.format(bridgeJoinClause.toString(), toAlias));
return clause.toString();
}
@Data
static class BridgeTableSelectCtx {
private final HashMap exprToDotAST = new HashMap<>();
private final List selectedBridgeExprs = new ArrayList<>();
private final AliasDecider aliasDecider = new DefaultAliasDecider("balias");
private final String bridgeTableFieldAggr;
private final String arrayFilter;
private final String tableAlias;
List processSelectAST(ASTNode selectAST)
throws LensException {
// iterate over children
for (int i = 0; i < selectAST.getChildCount(); i++) {
ASTNode selectExprNode = (ASTNode) selectAST.getChild(i);
ASTNode child = (ASTNode) selectExprNode.getChild(0);
if (hasBridgeCol(child, tableAlias)) {
selectExprNode.setChild(0, getDotASTForExprAST(child));
}
}
return selectedBridgeExprs;
}
private ASTNode getDotASTForExprAST(ASTNode child) {
HashableASTNode hashAST = new HashableASTNode(child);
if (!exprToDotAST.containsKey(hashAST)) {
// add selected expression to get selected from bridge table, with a generated alias
String colAlias = aliasDecider.decideAlias(child);
selectedBridgeExprs.add(bridgeTableFieldAggr + "(" + HQLParser.getString(child) + ") as " + colAlias);
// replace bridge expression with tableAlias.colAlias.
ASTNode dot = HQLParser.getDotAST(tableAlias, colAlias);
exprToDotAST.put(hashAST, dot);
}
return exprToDotAST.get(hashAST);
}
// process groupby
void processGroupbyAST(ASTNode ast)
throws LensException {
if (ast == null) {
return;
}
// iterate over children
for (int i = 0; i < ast.getChildCount(); i++) {
ASTNode exprNode = (ASTNode) ast.getChild(i);
if (hasBridgeCol(exprNode, tableAlias)) {
ast.setChild(i, getDotASTForExprAST(exprNode));
}
}
}
// process orderby
void processOrderbyAST(ASTNode ast)
throws LensException {
if (ast == null) {
return;
}
// iterate over children
for (int i = 0; i < ast.getChildCount(); i++) {
ASTNode exprNode = (ASTNode) ast.getChild(i);
ASTNode child = (ASTNode) exprNode.getChild(0);
if (hasBridgeCol(child, tableAlias)) {
exprNode.setChild(0, getDotASTForExprAST(child));
}
}
}
void processWhereClauses(DimHQLContext sc) throws LensException {
processWhereAST(sc.getQueryAst().getWhereAST(), null, 0);
}
void processWhereAST(ASTNode ast, ASTNode parent, int childPos)
throws LensException {
if (ast == null) {
return;
}
ASTNode child;
int replaceIndex = -1;
if (isPrimitiveBooleanExpression(ast)) {
replaceIndex = 0;
} else if (isPrimitiveBooleanFunction(ast)) {
replaceIndex = 1;
}
if (replaceIndex != -1) {
child = (ASTNode) ast.getChild(replaceIndex);
if (hasBridgeCol(child, tableAlias)) {
ast.setChild(replaceIndex, getDotASTForExprAST(child));
parent.setChild(childPos, replaceDirectFiltersWithArrayFilter(ast, arrayFilter));
}
}
// recurse down
for (int i = 0; i < ast.getChildCount(); i++) {
processWhereAST((ASTNode) ast.getChild(i), ast, i);
}
}
}
/**
* Update =, != and IN clause filters to arrayFilter. arrayFilter will have signature arrayFilter(col, value)
*
* @param ast AST for simple filter
* @param arrayFilter arrayFilter function
* @return ASTNode with converted filter
*
* @throws LensException
*/
static ASTNode replaceDirectFiltersWithArrayFilter(ASTNode ast, String arrayFilter)
throws LensException {
StringBuilder filterBuilder = new StringBuilder();
if ((ast.getType() == HiveParser.EQUAL || ast.getType() == HiveParser.NOTEQUAL)) {
String colStr = getString((ASTNode) ast.getChild(0));
if (ast.getType() == HiveParser.NOTEQUAL) {
filterBuilder.append(" NOT ");
}
filterBuilder.append(arrayFilter);
filterBuilder.append("(");
filterBuilder.append(colStr).append(",");
filterBuilder.append(getString((ASTNode)ast.getChild(1)));
filterBuilder.append(")");
} else if (ast.getType() == HiveParser.TOK_FUNCTION) {
// This is IN clause as function
String colStr = getString((ASTNode) ast.getChild(1));
filterBuilder.append("(");
for (int i = 2; i < ast.getChildCount(); i++) {
filterBuilder.append(arrayFilter);
filterBuilder.append("(");
filterBuilder.append(colStr).append(",");
filterBuilder.append(ast.getChild(i).getText());
filterBuilder.append(")");
if (i + 1 != ast.getChildCount()) {
filterBuilder.append(" OR ");
}
}
filterBuilder.append(")");
}
String finalFilter = filterBuilder.toString();
if (StringUtils.isNotBlank(finalFilter)) {
return HQLParser.parseExpr(finalFilter);
}
return ast;
}
static boolean hasBridgeCol(ASTNode astNode, String tableAlias) throws LensException {
Set bridgeCols = HQLParser.getColsInExpr(tableAlias, astNode);
return !bridgeCols.isEmpty();
}
}
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