[GitHub] vrozov commented on a change in pull request #1298: DRILL-5796: Filter pruning for multi rowgroup parquet file

[GitBox <gi...@apache.org>]

vrozov commented on a change in pull request #1298: DRILL-5796: Filter pruning for multi rowgroup parquet file
URL: https://github.com/apache/drill/pull/1298#discussion_r199868514
 
 

 ##########
 File path: exec/java-exec/src/main/java/org/apache/drill/exec/expr/stat/ParquetIsPredicate.java
 ##########
 @@ -62,90 +60,89 @@ private ParquetIsPredicate(LogicalExpression expr, BiPredicate<Statistics<C>, Ra
     return visitor.visitUnknown(this, value);
   }
 
-  @Override
-  public boolean canDrop(RangeExprEvaluator<C> evaluator) {
+  /**
+   * Apply the filter condition against the meta of the rowgroup.
+   */
+  public RowsMatch matches(RangeExprEvaluator<C> evaluator) {
     Statistics<C> exprStat = expr.accept(evaluator, null);
-    if (isNullOrEmpty(exprStat)) {
-      return false;
-    }
+    return ParquetPredicatesHelper.isNullOrEmpty(exprStat) ? RowsMatch.SOME : predicate.apply(exprStat, evaluator);
+  }
 
-    return predicate.test(exprStat, evaluator);
+  /**
+   * After the applying of the filter against the statistics of the rowgroup, if the result is RowsMatch.ALL,
+   * then we still must know if the rowgroup contains some null values, because it can change the filter result.
+   * If it contains some null values, then we change the RowsMatch.ALL into RowsMatch.SOME, which sya that maybe
+   * some values (the null ones) should be disgarded.
+   */
+  static RowsMatch checkNull(Statistics exprStat) {
+    return exprStat.getNumNulls() > 0 ? RowsMatch.SOME : RowsMatch.ALL;
   }
 
   /**
    * IS NULL predicate.
    */
   private static <C extends Comparable<C>> LogicalExpression createIsNullPredicate(LogicalExpression expr) {
     return new ParquetIsPredicate<C>(expr,
-        //if there are no nulls  -> canDrop
-        (exprStat, evaluator) -> hasNoNulls(exprStat)) {
-      private final boolean isArray = isArray(expr);
-
-      private boolean isArray(LogicalExpression expression) {
-        if (expression instanceof TypedFieldExpr) {
-          TypedFieldExpr typedFieldExpr = (TypedFieldExpr) expression;
-          SchemaPath schemaPath = typedFieldExpr.getPath();
-          return schemaPath.isArray();
-        }
-        return false;
-      }
-
-      @Override
-      public boolean canDrop(RangeExprEvaluator<C> evaluator) {
+      (exprStat, evaluator) -> {
         // for arrays we are not able to define exact number of nulls
         // [1,2,3] vs [1,2] -> in second case 3 is absent and thus it's null but statistics shows no nulls
-        return !isArray && super.canDrop(evaluator);
-      }
-    };
+        TypedFieldExpr typedFieldExpr = (TypedFieldExpr) expr;
+        if (typedFieldExpr.getPath().isArray()) {
+          return RowsMatch.SOME;
+        }
+        if (hasNoNulls(exprStat)) {
+          return RowsMatch.NONE;
+        }
+        return isAllNulls(exprStat, evaluator.getRowCount()) ? RowsMatch.ALL : RowsMatch.SOME;
+      });
   }
 
   /**
    * IS NOT NULL predicate.
    */
   private static <C extends Comparable<C>> LogicalExpression createIsNotNullPredicate(LogicalExpression expr) {
     return new ParquetIsPredicate<C>(expr,
-        //if there are all nulls  -> canDrop
-        (exprStat, evaluator) -> isAllNulls(exprStat, evaluator.getRowCount())
+      (exprStat, evaluator) -> isAllNulls(exprStat, evaluator.getRowCount()) ? RowsMatch.NONE : checkNull(exprStat)
     );
   }
 
   /**
    * IS TRUE predicate.
    */
-  private static LogicalExpression createIsTruePredicate(LogicalExpression expr) {
-    return new ParquetIsPredicate<Boolean>(expr,
-        //if max value is not true or if there are all nulls  -> canDrop
-        (exprStat, evaluator) -> !((BooleanStatistics)exprStat).getMax() || isAllNulls(exprStat, evaluator.getRowCount())
-    );
+  private static <C extends Comparable<C>> LogicalExpression createIsTruePredicate(LogicalExpression expr) {
+    return new ParquetIsPredicate<C>(expr,
+      (exprStat, evaluator) -> {
+        if (isAllNulls(exprStat, evaluator.getRowCount()) || (exprStat.genericGetMin().equals(Boolean.FALSE) && exprStat.genericGetMax().equals(Boolean.FALSE))) {
+          return RowsMatch.NONE;
+        }
+        return exprStat.genericGetMin().equals(Boolean.TRUE) && exprStat.genericGetMax().equals(Boolean.TRUE) ? checkNull(exprStat) : RowsMatch.SOME;
+      });
   }
 
   /**
    * IS FALSE predicate.
    */
-  private static LogicalExpression createIsFalsePredicate(LogicalExpression expr) {
-    return new ParquetIsPredicate<Boolean>(expr,
-        //if min value is not false or if there are all nulls  -> canDrop
-        (exprStat, evaluator) -> ((BooleanStatistics)exprStat).getMin() || isAllNulls(exprStat, evaluator.getRowCount())
+  private static <C extends Comparable<C>> LogicalExpression createIsFalsePredicate(LogicalExpression expr) {
+    return new ParquetIsPredicate<C>(expr,
+      (exprStat, evaluator) -> !exprStat.genericGetMin().equals(Boolean.FALSE) || isAllNulls(exprStat, evaluator.getRowCount()) ? RowsMatch.NONE : checkNull(exprStat)
     );
   }
 
   /**
    * IS NOT TRUE predicate.
    */
-  private static LogicalExpression createIsNotTruePredicate(LogicalExpression expr) {
-    return new ParquetIsPredicate<Boolean>(expr,
-        //if min value is not false or if there are no nulls  -> canDrop
-        (exprStat, evaluator) -> ((BooleanStatistics)exprStat).getMin() && hasNoNulls(exprStat)
+  private static <C extends Comparable<C>> LogicalExpression createIsNotTruePredicate(LogicalExpression expr) {
+    return new ParquetIsPredicate<C>(expr,
+      (exprStat, evaluator) -> !exprStat.genericGetMin().equals(Boolean.FALSE) && hasNoNulls(exprStat) ? RowsMatch.NONE : checkNull(exprStat)
     );
   }
 
   /**
    * IS NOT FALSE predicate.
    */
-  private static LogicalExpression createIsNotFalsePredicate(LogicalExpression expr) {
-    return new ParquetIsPredicate<Boolean>(expr,
-        //if max value is not true or if there are no nulls  -> canDrop
-        (exprStat, evaluator) -> !((BooleanStatistics)exprStat).getMax() && hasNoNulls(exprStat)
+  private static <C extends Comparable<C>> LogicalExpression createIsNotFalsePredicate(LogicalExpression expr) {
+    return new ParquetIsPredicate<C>(expr,
+      (exprStat, evaluator) -> !exprStat.genericGetMax().equals(Boolean.TRUE) && hasNoNulls(exprStat) ? RowsMatch.NONE : checkNull(exprStat)
 
 Review comment:
   "is true" can only be applied to a boolean expression and boolean expression can only produce `BooleanStatistics`. It is invalid anyway to compare `Integer`, `Long` or `Double` to `True` or `False`.

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