Ben-Zvi commented on a change in pull request #1598: DRILL-6880: For Hash-Join
hash-table build - treat null keys as an equal match
URL: https://github.com/apache/drill/pull/1598#discussion_r246238797
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/common/ChainedHashTable.java
##########
@@ -253,28 +277,29 @@ private void
setupIsKeyMatchInternal(ClassGenerator<HashTable> cg, MappingSet in
JConditional jc;
- // codegen for nullable columns if nulls are not equal
- if (comparators.get(i) == Comparator.EQUALS
- && left.isOptional() && right.isOptional()) {
- jc = cg.getEvalBlock()._if(left.getIsSet().eq(JExpr.lit(0)).
+ if ( work != setupWork.DO_BUILD ) { // BUILD runs this logic in a
separate method - areBothKeysNull()
+ // codegen for the special case when both columns are null (i.e.,
return early with midPointResult)
+ if (comparators.get(i) == Comparator.EQUALS
+ && left.isOptional() && right.isOptional()) {
+ jc = cg.getEvalBlock()._if(left.getIsSet().eq(JExpr.lit(0)).
cand(right.getIsSet().eq(JExpr.lit(0))));
- jc._then()._return(JExpr.FALSE);
+ jc._then()._return(midPointResult);
+ }
}
+ if ( ! checkIfBothNulls ) { // generate comparison code (at least one of
the two columns' values is non-null)
+ final LogicalExpression f =
FunctionGenerationHelper.getOrderingComparatorNullsHigh(left, right,
context.getFunctionRegistry());
- final LogicalExpression f =
- FunctionGenerationHelper
- .getOrderingComparatorNullsHigh(left, right,
context.getFunctionRegistry());
+ HoldingContainer out = cg.addExpr(f,
ClassGenerator.BlkCreateMode.FALSE);
- HoldingContainer out = cg.addExpr(f, ClassGenerator.BlkCreateMode.FALSE);
+ // check if two values are not equal (comparator result != 0)
+ jc = cg.getEvalBlock()._if(out.getValue().ne(JExpr.lit(0)));
- // check if two values are not equal (comparator result != 0)
- jc = cg.getEvalBlock()._if(out.getValue().ne(JExpr.lit(0)));
-
- jc._then()._return(JExpr.FALSE);
+ jc._then()._return(midPointResult);
+ }
}
// All key expressions compared equal, so return TRUE
- cg.getEvalBlock()._return(JExpr.TRUE);
+ cg.getEvalBlock()._return(finalResult);
Review comment:
Very observant ! The comment was re-written to be more general.
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