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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/1962/
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Review request for hive, Ning Zhang and namit jain.
Summary
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Some queries don't really need to access data when run - sometimes just
partition columns are involved. For example select max(hr) from some_table
where ds='2011-02-03'; and the table is partitioned by (ds, hr). Then we can't
omit reading files from HDFS speeding up the query. Such optimization can be
applied when we use just partition columns and all of these go through
aggregation - distinct or distinct-like (min, max - when many column vals act
just as one; when adding distinct keyword wouldn't change the result).
DUAL table is pseudo-table with no columns and one row. It is helpful when
testing UDFs - SELECT 2+2; returns parsing error, but we can use SELECT 2+2
FROM DUAL; and we get 4.
This addresses bugs HIVE-1003 and HIVE-1558.
https://issues.apache.org/jira/browse/HIVE-1003
https://issues.apache.org/jira/browse/HIVE-1558
Diffs
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trunk/common/src/java/org/apache/hadoop/hive/conf/HiveConf.java 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/exec/GroupByOperator.java 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/io/OneNullRowInputFormat.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/optimizer/GenMapRedUtils.java
1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/optimizer/Optimizer.java 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/optimizer/lineage/OpProcFactory.java
1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/optimizer/moq/MetadataOnlyOptimizer.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/optimizer/ppr/PartitionPruner.java
1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/parse/Hive.g 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/parse/ParseContext.java 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/parse/QB.java 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java
1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/plan/MapredMetadataWork.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/plan/MapredWork.java 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/plan/PlanUtils.java 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/udf/UDFType.java 1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDAFMax.java
1172965
trunk/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDAFMin.java
1172965
trunk/serde/src/java/org/apache/hadoop/hive/serde2/NullStructSerDe.java
PRE-CREATION
Diff: https://reviews.apache.org/r/1962/diff
Testing
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Simple unittests not attached here.
Thanks,
Marcin
