estimate is-null

englefly · Sep 22, 2023 · dd8a304 · dd8a304
1 parent 0d20a61
commit dd8a304
Showing 1 changed file with 14 additions and 0 deletions.
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java
@@ -28,6 +28,7 @@
 import org.apache.doris.nereids.trees.expressions.GreaterThan;
 import org.apache.doris.nereids.trees.expressions.GreaterThanEqual;
 import org.apache.doris.nereids.trees.expressions.InPredicate;
+import org.apache.doris.nereids.trees.expressions.IsNull;
 import org.apache.doris.nereids.trees.expressions.LessThan;
 import org.apache.doris.nereids.trees.expressions.LessThanEqual;
 import org.apache.doris.nereids.trees.expressions.Like;
@@ -386,6 +387,19 @@ public Statistics visitNot(Not not, EstimationContext context) {
         return statisticsBuilder.build();
     }
 
+    @Override
+    public Statistics visitIsNull(IsNull isNull, EstimationContext context) {
+        ColumnStatistic childStats = ExpressionEstimation.estimate(isNull.child(), context.statistics);
+        if (childStats.isUnKnown()) {
+            return new StatisticsBuilder(context.statistics).build();
+        }
+        double outputRowCount = context.statistics.getRowCount() - childStats.numNulls;
+        StatisticsBuilder builder = new StatisticsBuilder(context.statistics);
+        builder.putColumnStatistics(isNull.child(), childStats);
+        Statistics outputStats = builder.build().updateRowCountOnly(outputRowCount);
+        return outputStats;
+    }
+
     static class EstimationContext {
         private final Statistics statistics;