Github user amansinha100 commented on a diff in the pull request:
https://github.com/apache/drill/pull/462#discussion_r59941224
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/common/HashTableConfig.java
---
@@ -22,25 +22,36 @@
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonTypeName;
+import org.apache.drill.exec.physical.impl.join.JoinUtils.JoinComparator;
@JsonTypeName("hashtable-config")
public class HashTableConfig {
- static final org.slf4j.Logger logger =
org.slf4j.LoggerFactory.getLogger(HashTableConfig.class);
-
private final int initialCapacity;
private final float loadFactor;
private final NamedExpression[] keyExprsBuild;
private final NamedExpression[] keyExprsProbe;
+ private final JoinComparator[] comparators;
@JsonCreator
public HashTableConfig(@JsonProperty("initialCapacity") int
initialCapacity, @JsonProperty("loadFactor") float loadFactor,
@JsonProperty("keyExprsBuild") NamedExpression[]
keyExprsBuild,
- @JsonProperty("keyExprsProbe") NamedExpression[]
keyExprsProbe) {
+ @JsonProperty("keyExprsProbe") NamedExpression[]
keyExprsProbe,
+ @JsonProperty("comparators") JoinComparator[]
comparators) {
this.initialCapacity = initialCapacity;
this.loadFactor = loadFactor;
this.keyExprsBuild = keyExprsBuild;
this.keyExprsProbe = keyExprsProbe;
+ if (comparators != null) {
+ this.comparators = comparators;
+ } else {
+ // default is nulls are equal
--- End diff --
It might seem confusing at first (it was to me) to consider the
nulls-are-equal as the default case since that's not true for joins; however it
is true for a group-by operation. Could you have the caller pass in explicit
comparator such that the HashTableConfig does not have to decide ? The
HashAggregate could instantiate the hash table with an IS_NOT_DISTINCT_FROM
comparator. What do you think ? (one minor point is that the 'JoinComparator'
is now being used for both Joins and Aggregates...we could call it Comparator
or something generic).
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