/**
* Analyze aggregation-relevant components of the select block (Group By clause, select list,
* Order By clause), substitute AVG with SUM/COUNT, create the AggregationInfo, including the agg
* output tuple, and transform all post-agg exprs given AggregationInfo's smap.
*
* @param analyzer
* @throws AnalysisException
*/
private void analyzeAggregation(Analyzer analyzer) throws AnalysisException, InternalException {
if (groupingExprs == null
&& !selectList.isDistinct()
&& !Expr.contains(resultExprs, AggregateExpr.class)) {
// we're not computing aggregates
return;
}
// If we're computing an aggregate, we must have a FROM clause.
if (tableRefs.size() == 0) {
throw new AnalysisException("aggregation without a FROM clause is not allowed");
}
if ((groupingExprs != null || Expr.contains(resultExprs, AggregateExpr.class))
&& selectList.isDistinct()) {
throw new AnalysisException(
"cannot combine SELECT DISTINCT with aggregate functions or GROUP BY");
}
// disallow '*' and explicit GROUP BY (we can't group by '*', and if you need to
// name all star-expanded cols in the group by clause you might as well do it
// in the select list)
if (groupingExprs != null) {
for (SelectListItem item : selectList.getItems()) {
if (item.isStar()) {
throw new AnalysisException(
"cannot combine '*' in select list with GROUP BY: " + item.toSql());
}
}
}
// analyze grouping exprs
ArrayList<Expr> groupingExprsCopy = Lists.newArrayList();
if (groupingExprs != null) {
// make a deep copy here, we don't want to modify the original
// exprs during analysis (in case we need to print them later)
groupingExprsCopy = Expr.cloneList(groupingExprs, null);
substituteOrdinals(groupingExprsCopy, "GROUP BY");
Expr ambiguousAlias = getFirstAmbiguousAlias(groupingExprsCopy);
if (ambiguousAlias != null) {
throw new AnalysisException(
"Column " + ambiguousAlias.toSql() + " in group by clause is ambiguous");
}
Expr.substituteList(groupingExprsCopy, aliasSMap);
for (int i = 0; i < groupingExprsCopy.size(); ++i) {
groupingExprsCopy.get(i).analyze(analyzer);
if (groupingExprsCopy.get(i).contains(AggregateExpr.class)) {
// reference the original expr in the error msg
throw new AnalysisException(
"GROUP BY expression must not contain aggregate functions: "
+ groupingExprs.get(i).toSql());
}
}
}
// analyze having clause
if (havingClause != null) {
// substitute aliases in place (ordinals not allowed in having clause)
havingPred = havingClause.clone(aliasSMap);
havingPred.analyze(analyzer);
havingPred.checkReturnsBool("HAVING clause", true);
analyzer.registerConjuncts(havingPred, null, false);
}
List<Expr> orderingExprs = null;
if (sortInfo != null) {
orderingExprs = sortInfo.getOrderingExprs();
}
ArrayList<AggregateExpr> aggExprs = collectAggExprs();
Expr.SubstitutionMap avgSMap = createAvgSMap(aggExprs, analyzer);
// substitute AVG before constructing AggregateInfo
Expr.substituteList(aggExprs, avgSMap);
ArrayList<AggregateExpr> nonAvgAggExprs = Lists.newArrayList();
Expr.collectList(aggExprs, AggregateExpr.class, nonAvgAggExprs);
aggExprs = nonAvgAggExprs;
createAggInfo(groupingExprsCopy, aggExprs, analyzer);
// combine avg smap with the one that produces the final agg output
AggregateInfo finalAggInfo =
aggInfo.getSecondPhaseDistinctAggInfo() != null
? aggInfo.getSecondPhaseDistinctAggInfo()
: aggInfo;
Expr.SubstitutionMap combinedSMap =
Expr.SubstitutionMap.combine(avgSMap, finalAggInfo.getSMap());
LOG.debug("combined smap: " + combinedSMap.debugString());
// change select list, having and ordering exprs to point to agg output
Expr.substituteList(resultExprs, combinedSMap);
LOG.debug("post-agg selectListExprs: " + Expr.debugString(resultExprs));
if (havingPred != null) {
havingPred = havingPred.substitute(combinedSMap);
LOG.debug("post-agg havingPred: " + havingPred.debugString());
}
Expr.substituteList(orderingExprs, combinedSMap);
LOG.debug("post-agg orderingExprs: " + Expr.debugString(orderingExprs));
// check that all post-agg exprs point to agg output
for (int i = 0; i < selectList.getItems().size(); ++i) {
if (!resultExprs.get(i).isBound(finalAggInfo.getAggTupleId())) {
throw new AnalysisException(
"select list expression not produced by aggregation output "
+ "(missing from GROUP BY clause?): "
+ selectList.getItems().get(i).getExpr().toSql());
}
}
if (orderByElements != null) {
for (int i = 0; i < orderByElements.size(); ++i) {
if (!orderingExprs.get(i).isBound(finalAggInfo.getAggTupleId())) {
throw new AnalysisException(
"ORDER BY expression not produced by aggregation output "
+ "(missing from GROUP BY clause?): "
+ orderByElements.get(i).getExpr().toSql());
}
}
}
if (havingPred != null) {
if (!havingPred.isBound(finalAggInfo.getAggTupleId())) {
throw new AnalysisException(
"HAVING clause not produced by aggregation output "
+ "(missing from GROUP BY clause?): "
+ havingClause.toSql());
}
}
}
/**
* Analyze aggregation-relevant components of the select block (Group By clause, select list,
* Order By clause), substitute AVG with SUM/COUNT, create the AggregationInfo, including the agg
* output tuple, and transform all post-agg exprs given AggregationInfo's smap.
*/
private void analyzeAggregation(Analyzer analyzer)
throws AnalysisException, AuthorizationException {
if (groupingExprs_ == null
&& !selectList_.isDistinct()
&& !TreeNode.contains(resultExprs_, Expr.isAggregatePredicate())) {
// we're not computing aggregates
return;
}
// If we're computing an aggregate, we must have a FROM clause.
if (tableRefs_.size() == 0) {
throw new AnalysisException("aggregation without a FROM clause is not allowed");
}
if ((groupingExprs_ != null || TreeNode.contains(resultExprs_, Expr.isAggregatePredicate()))
&& selectList_.isDistinct()) {
throw new AnalysisException(
"cannot combine SELECT DISTINCT with aggregate functions or GROUP BY");
}
// disallow '*' and explicit GROUP BY (we can't group by '*', and if you need to
// name all star-expanded cols in the group by clause you might as well do it
// in the select list)
if (groupingExprs_ != null) {
for (SelectListItem item : selectList_.getItems()) {
if (item.isStar()) {
throw new AnalysisException(
"cannot combine '*' in select list with GROUP BY: " + item.toSql());
}
}
}
// analyze grouping exprs
ArrayList<Expr> groupingExprsCopy = Lists.newArrayList();
if (groupingExprs_ != null) {
// make a deep copy here, we don't want to modify the original
// exprs during analysis (in case we need to print them later)
groupingExprsCopy = Expr.cloneList(groupingExprs_);
substituteOrdinals(groupingExprsCopy, "GROUP BY");
Expr ambiguousAlias = getFirstAmbiguousAlias(groupingExprsCopy);
if (ambiguousAlias != null) {
throw new AnalysisException(
"Column " + ambiguousAlias.toSql() + " in group by clause is ambiguous");
}
Expr.substituteList(groupingExprsCopy, aliasSmap_);
for (int i = 0; i < groupingExprsCopy.size(); ++i) {
groupingExprsCopy.get(i).analyze(analyzer);
if (groupingExprsCopy.get(i).contains(Expr.isAggregatePredicate())) {
// reference the original expr in the error msg
throw new AnalysisException(
"GROUP BY expression must not contain aggregate functions: "
+ groupingExprs_.get(i).toSql());
}
}
}
// analyze having clause
if (havingClause_ != null) {
// substitute aliases in place (ordinals not allowed in having clause)
havingPred_ = havingClause_.clone(aliasSmap_);
havingPred_.analyze(analyzer);
havingPred_.checkReturnsBool("HAVING clause", true);
}
List<Expr> orderingExprs = null;
if (sortInfo_ != null) orderingExprs = sortInfo_.getOrderingExprs();
// Collect the aggregate expressions from the SELECT, HAVING and ORDER BY clauses
// of this statement.
ArrayList<FunctionCallExpr> aggExprs = Lists.newArrayList();
TreeNode.collect(resultExprs_, Expr.isAggregatePredicate(), aggExprs);
if (havingPred_ != null) {
havingPred_.collect(Expr.isAggregatePredicate(), aggExprs);
}
if (sortInfo_ != null) {
TreeNode.collect(sortInfo_.getOrderingExprs(), Expr.isAggregatePredicate(), aggExprs);
}
// substitute AVG before constructing AggregateInfo
Expr.SubstitutionMap avgSMap = createAvgSMap(aggExprs, analyzer);
ArrayList<Expr> substitutedAggs = Expr.cloneList(aggExprs, avgSMap);
ArrayList<FunctionCallExpr> nonAvgAggExprs = Lists.newArrayList();
TreeNode.collect(substitutedAggs, Expr.isAggregatePredicate(), nonAvgAggExprs);
// When DISTINCT aggregates are present, non-distinct (i.e. ALL) aggregates are
// evaluated in two phases (see AggregateInfo for more details). In particular,
// COUNT(c) in "SELECT COUNT(c), AGG(DISTINCT d) from R" is transformed to
// "SELECT SUM(cnt) FROM (SELECT COUNT(c) as cnt from R group by d ) S".
// Since a group-by expression is added to the inner query it returns no rows if
// R is empty, in which case the SUM of COUNTs will return NULL.
// However the original COUNT(c) should have returned 0 instead of NULL in this case.
// Therefore, COUNT([ALL]) is transformed into zeroifnull(COUNT([ALL]) if
// i) There is no GROUP-BY clause, and
// ii) Other DISTINCT aggregates are present.
Expr.SubstitutionMap countAllMap = createCountAllMap(nonAvgAggExprs, analyzer);
substitutedAggs = Expr.cloneList(nonAvgAggExprs, countAllMap);
aggExprs.clear();
TreeNode.collect(substitutedAggs, Expr.isAggregatePredicate(), aggExprs);
try {
createAggInfo(groupingExprsCopy, aggExprs, analyzer);
} catch (InternalException e) {
throw new AnalysisException(e.getMessage(), e);
}
// combine avg smap with the one that produces the final agg output
AggregateInfo finalAggInfo =
aggInfo_.getSecondPhaseDistinctAggInfo() != null
? aggInfo_.getSecondPhaseDistinctAggInfo()
: aggInfo_;
Expr.SubstitutionMap combinedSMap =
Expr.SubstitutionMap.compose(
Expr.SubstitutionMap.compose(avgSMap, countAllMap), finalAggInfo.getSMap());
LOG.debug("combined smap: " + combinedSMap.debugString());
// change select list, having and ordering exprs to point to agg output
Expr.substituteList(resultExprs_, combinedSMap);
LOG.debug("post-agg selectListExprs: " + Expr.debugString(resultExprs_));
if (havingPred_ != null) {
havingPred_ = havingPred_.substitute(combinedSMap);
analyzer.registerConjuncts(havingPred_, null, false);
LOG.debug("post-agg havingPred: " + havingPred_.debugString());
}
Expr.substituteList(orderingExprs, combinedSMap);
LOG.debug("post-agg orderingExprs: " + Expr.debugString(orderingExprs));
// check that all post-agg exprs point to agg output
for (int i = 0; i < selectList_.getItems().size(); ++i) {
if (!resultExprs_.get(i).isBound(finalAggInfo.getAggTupleId())) {
throw new AnalysisException(
"select list expression not produced by aggregation output "
+ "(missing from GROUP BY clause?): "
+ selectList_.getItems().get(i).getExpr().toSql());
}
}
if (orderByElements_ != null) {
for (int i = 0; i < orderByElements_.size(); ++i) {
if (!orderingExprs.get(i).isBound(finalAggInfo.getAggTupleId())) {
throw new AnalysisException(
"ORDER BY expression not produced by aggregation output "
+ "(missing from GROUP BY clause?): "
+ orderByElements_.get(i).getExpr().toSql());
}
}
}
if (havingPred_ != null) {
if (!havingPred_.isBound(finalAggInfo.getAggTupleId())) {
throw new AnalysisException(
"HAVING clause not produced by aggregation output "
+ "(missing from GROUP BY clause?): "
+ havingClause_.toSql());
}
}
}