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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/21549/
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Review request for hive.
Bugs: HIVE-4867
https://issues.apache.org/jira/browse/HIVE-4867
Repository: hive-git
Description
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A ReduceSinkOperator emits data in the format of keys and values. Right now, a
column may appear in both the key list and value list, which result in
unnecessary overhead for shuffling.
Example:
We have a query shown below ...
{code:sql}
explain select ss_ticket_number from store_sales cluster by ss_ticket_number;
{\code}
The plan is ...
{code}
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-0 is a root stage
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
store_sales
TableScan
alias: store_sales
Select Operator
expressions:
expr: ss_ticket_number
type: int
outputColumnNames: _col0
Reduce Output Operator
key expressions:
expr: _col0
type: int
sort order: +
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col0
type: int
Reduce Operator Tree:
Extract
File Output Operator
compressed: false
GlobalTableId: 0
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format:
org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
Stage: Stage-0
Fetch Operator
limit: -1
{\code}
The column 'ss_ticket_number' is in both the key list and value list of the
ReduceSinkOperator. The type of ss_ticket_number is int. For this case,
BinarySortableSerDe will introduce 1 byte more for every int in the key.
LazyBinarySerDe will also introduce overhead when recording the length of a
int. For every int, 10 bytes should be a rough estimation of the size of data
emitted from the Map phase.
Diffs
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ql/src/java/org/apache/hadoop/hive/ql/Driver.java 9040d9b
ql/src/java/org/apache/hadoop/hive/ql/exec/ColumnInfo.java acaca23
ql/src/java/org/apache/hadoop/hive/ql/exec/MapOperator.java fc5864a
ql/src/java/org/apache/hadoop/hive/ql/exec/Operator.java 22374b2
ql/src/java/org/apache/hadoop/hive/ql/exec/ReduceSinkOperator.java 6368548
ql/src/java/org/apache/hadoop/hive/ql/exec/RowSchema.java 083d574
ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java 7250432
ql/src/java/org/apache/hadoop/hive/ql/hooks/LineageInfo.java 22a8785
ql/src/java/org/apache/hadoop/hive/ql/optimizer/ColumnPrunerProcFactory.java
6a4dc9b
ql/src/java/org/apache/hadoop/hive/ql/optimizer/MapJoinProcessor.java e3e0acc
ql/src/java/org/apache/hadoop/hive/ql/optimizer/correlation/CorrelationOptimizer.java
86e4834
ql/src/java/org/apache/hadoop/hive/ql/optimizer/correlation/ReduceSinkDeDuplication.java
719fe9f
ql/src/java/org/apache/hadoop/hive/ql/optimizer/lineage/ExprProcCtx.java
7cf48a7
ql/src/java/org/apache/hadoop/hive/ql/optimizer/lineage/ExprProcFactory.java
b5cdde1
ql/src/java/org/apache/hadoop/hive/ql/optimizer/lineage/OpProcFactory.java
78b7ca8
ql/src/java/org/apache/hadoop/hive/ql/optimizer/physical/BucketingSortingOpProcFactory.java
eac0edd
ql/src/java/org/apache/hadoop/hive/ql/parse/RowResolver.java f142f3e
ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java 49eb83f
ql/src/java/org/apache/hadoop/hive/ql/ppd/ExprWalkerProcFactory.java 4175d11
ql/src/java/org/apache/hadoop/hive/ql/session/LineageState.java e706f52
Diff: https://reviews.apache.org/r/21549/diff/
Testing
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Thanks,
Navis Ryu
