gparai commented on a change in pull request #1744: Drill 7148 - Join order,
multi-col ndv and aggregate rowcount fixes for TPCH queries
URL: https://github.com/apache/drill/pull/1744#discussion_r275195176
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/cost/DrillRelMdDistinctRowCount.java
##########
@@ -148,29 +154,59 @@ private Double getDistinctRowCount(DrillScanRelBase
scan, RelMetadataQuery mq, D
// Statistics cannot be obtained, use default behaviour
return scan.estimateRowCount(mq) * 0.1;
}
- double s = 1.0;
- for (int i = 0; i < groupKey.length(); i++) {
- final String colName = type.getFieldNames().get(i);
- // Skip NDV, if not available
- if (!groupKey.get(i)) {
- continue;
+ double s = 1.0;
+ if (((int)PrelUtil.getPlannerSettings(
+ scan.getCluster().getPlanner()).getStatisticsJoinCardinalityMode() &
2) == 2) {
+ for (int i = 0; i < groupKey.length(); i++) {
+ final String colName = type.getFieldNames().get(i);
+ // Skip NDV, if not available
+ if (!groupKey.get(i)) {
+ continue;
+ }
+ ColumnStatistics columnStatistics = tableMetadata != null ?
tableMetadata.getColumnStatistics(SchemaPath.getSimplePath(colName)) : null;
+ Double ndv = columnStatistics != null ? (Double)
columnStatistics.getStatistic(ColumnStatisticsKind.NVD) : null;
Review comment:
Done
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