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https://reviews.apache.org/r/39248/
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Review request for hive.
Bugs: HIVE-12082
https://issues.apache.org/jira/browse/HIVE-12082
Repository: hive-git
Description
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See HIVE-12070 and HIVE-12082 for discussions and findings. Refactored the
Greatest/Least UDF's to be inline with the SQL-standard spec of comparison
operators, and the mysql implementation of greatest/least functional UDF's.
The main functional changes is that:
1. Different types can be compared now, but used to throw an exception.
Comparison uses the same logic as binary comparison operators, ie greaterThan.
2. If any argument is NULL, the result is null. NULLs used to be ignored in
the comparison in favor of non-null values, which violates the SQL-standard.
Code changes:
Common logics is captured in the new class 'GenericUDFBaseNWayCompare', which
does a linear comparison in the two-cases where arguments are of same type and
different type, in the latter it uses Converters. The class that it uses is
ObjectInspectorUtils.compare(), which is the same as the binary comparison
operators.
Diffs
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ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFBaseNwayCompare.java
PRE-CREATION
ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFGreatest.java
e1eab89
ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFLeast.java
64a1b47
ql/src/test/org/apache/hadoop/hive/ql/udf/generic/TestGenericUDFGreatest.java
55d7d5d
ql/src/test/org/apache/hadoop/hive/ql/udf/generic/TestGenericUDFLeast.java
47e4801
ql/src/test/queries/clientnegative/udf_greatest_error_2.q b270a1a
ql/src/test/queries/clientnegative/udf_greatest_error_3.q ba21748
ql/src/test/queries/clientnegative/udf_greatest_error_4.q ae6d928
ql/src/test/queries/clientpositive/udf_greatest.q 02c7d3c
ql/src/test/queries/clientpositive/udf_least.q a754ef0
ql/src/test/results/clientnegative/udf_greatest_error_2.q.out 9a6348c
ql/src/test/results/clientnegative/udf_greatest_error_3.q.out 3fb3499
ql/src/test/results/clientnegative/udf_greatest_error_4.q.out 58b4c44
ql/src/test/results/clientpositive/udf_greatest.q.out 10f1c2d
ql/src/test/results/clientpositive/udf_least.q.out 6983137
Diff: https://reviews.apache.org/r/39248/diff/
Testing
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Added more unit tests, and q tests.
Thanks,
Szehon Ho
