Github user jinfengni commented on a diff in the pull request:
https://github.com/apache/drill/pull/416#discussion_r55454105
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/physical/ConvertCountToDirectScan.java
---
@@ -117,6 +117,24 @@ public void onMatch(RelOptRuleCall call) {
} else if (aggCall.getArgList().size() == 1) {
// count(columnName) ==> Agg ( Scan )) ==> columnValueCount
int index = aggCall.getArgList().get(0);
+
+ if (proj != null) {
+ // project in the middle of Agg and Scan : Only when input of
AggCall is a RexInputRef in Project, we find the index of Scan's field.
+ // For instance,
+ // Agg - count($0)
+ // \
+ // Proj - Exp={$1}
+ // \
+ // Scan (col1, col2).
+ // return count of "col2" in Scan's metadata, if found.
+
+ if (proj.getProjects().get(index) instanceof RexInputRef) {
+ index = ((RexInputRef)
proj.getProjects().get(index)).getIndex();
--- End diff --
Calcite rewrote count(100) or count(1) into count() ==>
aggCall.getArgList.isEmpty() is true. So Line 113 will take care of those
cases.
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