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_r198896839
##########
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;
Review comment:
private? consider using `hasNoNulls()`: `return hasNoNulls(exprStat) ?
RowsMatch.ALL : RowsMatch.SOME;`
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