kgyrtkirk commented on a change in pull request #544: HIVE-16924 Support
distinct in presence of Group By
URL: https://github.com/apache/hive/pull/544#discussion_r259778186
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File path: ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java
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@@ -4194,27 +4191,29 @@ public static long unsetBit(long bitmap, int bitIdx) {
}
/**
- * This function is a wrapper of parseInfo.getGroupByForClause which
- * automatically translates SELECT DISTINCT a,b,c to SELECT a,b,c GROUP BY
- * a,b,c.
+ * Returns the GBY, if present;
+ * DISTINCT, if present, will be handled when generating the SELECT.
*/
List<ASTNode> getGroupByForClause(QBParseInfo parseInfo, String dest) throws
SemanticException {
- if (parseInfo.getSelForClause(dest).getToken().getType() ==
HiveParser.TOK_SELECTDI) {
- ASTNode selectExprs = parseInfo.getSelForClause(dest);
- List<ASTNode> result = new ArrayList<ASTNode>(selectExprs == null ? 0
- : selectExprs.getChildCount());
- if (selectExprs != null) {
- for (int i = 0; i < selectExprs.getChildCount(); ++i) {
- if (((ASTNode) selectExprs.getChild(i)).getToken().getType() ==
HiveParser.QUERY_HINT) {
+ // When *not* invoked by CalcitePlanner, return the DISTINCT as a GBY
+ // CBO will handle the DISTINCT in
CalcitePlannerAction.genSelectLogicalPlan
+ ASTNode selectExpr = parseInfo.getSelForClause(dest);
+ Collection<ASTNode> aggregateFunction =
parseInfo.getDestToAggregationExprs().get(dest).values();
+ if (isSelectDistinct(selectExpr) && !isGroupBy(selectExpr) &&
!isAggregateInSelect(selectExpr, aggregateFunction)) {
Review comment:
what plan are we ending up if we have select distinct which has an aggregate
(this condition will be false) and the cbo is not working? is there a test for
that?
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