zabetak commented on a change in pull request #1544:
URL: https://github.com/apache/hive/pull/1544#discussion_r504638460
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File path: ql/src/java/org/apache/hadoop/hive/ql/plan/ExprNodeDescUtils.java
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@@ -233,6 +235,23 @@ public static ExprNodeGenericFuncDesc
and(List<ExprNodeDesc> exps) {
return new ExprNodeGenericFuncDesc(TypeInfoFactory.booleanTypeInfo, new
GenericUDFOPAnd(), "and", flatExps);
}
+ /**
+ * Create an expression for computing a hash by recursively hashing given
expressions by two:
+ * <pre>
+ * Input: HASH(A, B, C, D)
+ * Output: HASH(HASH(HASH(A,B),C),D)
+ * </pre>
+ */
+ public static ExprNodeGenericFuncDesc hash(List<ExprNodeDesc> exps) {
+ assert exps.size() >= 2;
+ ExprNodeDesc hashExp = exps.get(0);
+ for (int i = 1; i < exps.size(); i++) {
+ List<ExprNodeDesc> hArgs = Arrays.asList(hashExp, exps.get(i));
+ hashExp = new ExprNodeGenericFuncDesc(TypeInfoFactory.intTypeInfo, new
GenericUDFMurmurHash(), "hash", hArgs);
Review comment:
Good catch @kgyrtkirk ! I've never noticed that we have two different
UDFs for hashing. Indeed having the same annotation can create quite some
confusion and difficult to debug problems. I guess your suggestion is to change
the annotation of GenericUDFMurmurHash to murmur_hash right?
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