bupt04406
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lvyuan1234：
你好，你那个sample.txt文件可以分享给我吗
hive insert overwrite into -
107x：
不错，谢谢！
hive 表的一些默认值 -
on_way_：
赞
Hadoop相关书籍 -
bupt04406：
dengkanghua 写道出来这个问题该怎么解决？hbase ...
Unexpected state导致HMaster abort -
dengkanghua：
出来这个问题该怎么解决？hbase master启动不起来。
Unexpected state导致HMaster abort
hive> select distinct value from src;
hive> select max(key) from src;
因为没有grouping keys，所以只有一个reducer。
2.2 如果有聚合函数或者groupby，做如下处理：
插入一个select operator，选取所有的字段，用于优化阶段ColumnPruner的优化
2.2.1 hive.map.aggr为true，默认是true，开启的，在map端做部分聚合
2.2.1.1 hive.groupby.skewindata为false，默认是关闭的，groupby的数据没有倾斜。
生成的operator是: GroupByOperator+ReduceSinkOperator+GroupByOperator。
GroupByOperator+ReduceSinkOperator用于在map端做操作，第一个GroupByOperator在map端先做部分聚合。第二个用于在reduce端做GroupBy操作
2.2.1.2 hive.groupby.skewindata为true
生成的operator是: GroupbyOperator+ReduceSinkOperator+GroupbyOperator+ReduceSinkOperator +GroupByOperator
GroupbyOperator+ReduceSinkOperator（第一个MapredTask的map阶段）
GroupbyOperator(第一个MapredTask的reduce阶段)
ReduceSinkOperator （第二个MapredTask的map阶段）
GroupByOperator（第二个MapredTask的reduce阶段）
2.2.2 hive.map.aggr为false
2.2.2.1 hive.groupby.skewindata为true
生成的operator是: ReduceSinkOperator+GroupbyOperator+ReduceSinkOperator +GroupByOperator
ReduceSinkOperator(第一个MapredTask的map阶段)
GroupbyOperator(第一个MapredTask的reduce阶段)
ReduceSinkOperator （第二个MapredTask的map阶段）
GroupByOperator（第二个MapredTask的reduce阶段）
2.2.2.2 hive.groupby.skewindata为false
生成的operator是: ReduceSinkOperator(map阶段运行)+GroupbyOperator（reduce阶段运行）
第一种情况：
set hive.map.aggr=false;
set hive.groupby.skewindata=false;
SemanticAnalyzer.genGroupByPlan1MR(){
（1）ReduceSinkOperator： It will put all Group By keys and the distinct field (if any) in the map-reduce sort key, and all other fields in the map-reduce value.
（2）GroupbyOperator：GroupByDesc.Mode.COMPLETE，Reducer: iterate/merge (mode = COMPLETE)
}
第二种情况：
set hive.map.aggr=true;
set hive.groupby.skewindata=false;
SemanticAnalyzer.genGroupByPlanMapAggr1MR(){
（1）GroupByOperator：GroupByDesc.Mode.HASH，The agggregation evaluation functions are as follows: Mapper: iterate/terminatePartial (mode = HASH)
（2）ReduceSinkOperator：Partitioning Key: grouping key。Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT
（3）GroupByOperator：GroupByDesc.Mode.MERGEPARTIAL，Reducer: iterate/terminate if DISTINCT merge/terminate if NO DISTINCT (mode = MERGEPARTIAL)
}
第三种情况：
set hive.map.aggr=false;
set hive.groupby.skewindata=true;
SemanticAnalyzer.genGroupByPlan2MR(){
（1）ReduceSinkOperator：Partitioning Key: random() if no DISTINCT grouping + distinct key if DISTINCT。Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT
（2）GroupbyOperator：GroupByDesc.Mode.PARTIAL1，Reducer: iterate/terminatePartial (mode = PARTIAL1)
（3）ReduceSinkOperator：Partitioning Key: grouping key。Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT
（4）GroupByOperator：GroupByDesc.Mode.FINAL，Reducer: merge/terminate (mode = FINAL)
}
第四种情况：
set hive.map.aggr=true;
set hive.groupby.skewindata=true;
SemanticAnalyzer.genGroupByPlanMapAggr2MR(){
（1）GroupbyOperator：GroupByDesc.Mode.HASH，Mapper: iterate/terminatePartial (mode = HASH)
（2）ReduceSinkOperator： Partitioning Key: random() if no DISTINCT grouping + distinct key if DISTINCT。 Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT。
（3）GroupbyOperator：GroupByDesc.Mode.PARTIALS， Reducer: iterate/terminatePartial if DISTINCT merge/terminatePartial if NO DISTINCT (mode = MERGEPARTIAL)
（4）ReduceSinkOperator：Partitioining Key: grouping key。Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT
（5）GroupByOperator：GroupByDesc.Mode.FINAL，Reducer: merge/terminate (mode = FINAL)
}
ReduceSinkOperator的processOp(Object row, int tag)会根据相应的条件设置Key的hash值，如第四种情况的第一个ReduceSinkOperator：Partitioning Key: random() if no DISTINCT grouping + distinct key if DISTINCT，如果没有DISTINCT字段，那么在OutputCollector.collect前会设置当前Key的hash值为一个随机数，random = new Random(12345);。如果有DISTINCT字段，那么key的hash值跟grouping + distinct key有关。
GroupByOperator：
initializeOp(Configuration hconf)
processOp(Object row, int tag)
closeOp(boolean abort)
forward(ArrayList<Object> keys, AggregationBuffer[] aggs)
groupby10.q groupby11.q
set hive.map.aggr=false;
set hive.groupby.skewindata=false;
EXPLAIN
FROM INPUT
INSERT OVERWRITE TABLE dest1 SELECT INPUT.key, count(substr(INPUT.value,5)), count(distinct substr(INPUT.value,5)) GROUP BY INPUT.key;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-0 depends on stages: Stage-1
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator // insertSelectAllPlanForGroupBy
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Reduce Output Operator
key expressions:
expr: key
type: int
expr: substr(value, 5)
type: string
sort order: ++
Map-reduce partition columns:
expr: key
type: int
tag: -1
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(KEY._col1:0._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: complete
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
Stage: Stage-0
Move Operator
tables:
replace: true
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
set hive.map.aggr=true;
set hive.groupby.skewindata=false;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-0 depends on stages: Stage-1
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Group By Operator
aggregations:
expr: count(substr(value, 5))
expr: count(DISTINCT substr(value, 5))
bucketGroup: false
keys:
expr: key
type: int
expr: substr(value, 5)
type: string
mode: hash
outputColumnNames: _col0, _col1, _col2, _col3
Reduce Output Operator
key expressions:
expr: _col0
type: int
expr: _col1
type: string
sort order: ++
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col2
type: bigint
expr: _col3
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: mergepartial
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
Stage: Stage-0
Move Operator
tables:
replace: true
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
set hive.map.aggr=false;
set hive.groupby.skewindata=true;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-2 depends on stages: Stage-1
Stage-0 depends on stages: Stage-2
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Reduce Output Operator
key expressions:
expr: key
type: int
expr: substr(value, 5)
type: string
sort order: ++
Map-reduce partition columns:
expr: key
type: int
tag: -1
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(KEY._col1:0._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: partial1
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 0
table:
input format: org.apache.hadoop.mapred.SequenceFileInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
Stage: Stage-2
Map Reduce
Alias -> Map Operator Tree:
hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-48-26_387_7978992474997402829/-mr-10002
Reduce Output Operator
key expressions:
expr: _col0
type: int
sort order: +
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col1
type: bigint
expr: _col2
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
expr: count(VALUE._col1)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: final
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
Stage: Stage-0
Move Operator
tables:
replace: true
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
set hive.map.aggr=true;
set hive.groupby.skewindata=true;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-2 depends on stages: Stage-1
Stage-0 depends on stages: Stage-2
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Group By Operator
aggregations:
expr: count(substr(value, 5))
expr: count(DISTINCT substr(value, 5))
bucketGroup: false
keys:
expr: key
type: int
expr: substr(value, 5)
type: string
mode: hash
outputColumnNames: _col0, _col1, _col2, _col3
Reduce Output Operator
key expressions:
expr: _col0
type: int
expr: _col1
type: string
sort order: ++
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col2
type: bigint
expr: _col3
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: partials
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 0
table:
input format: org.apache.hadoop.mapred.SequenceFileInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
Stage: Stage-2
Map Reduce
Alias -> Map Operator Tree:
hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-49-25_899_4946067838822964610/-mr-10002
Reduce Output Operator
key expressions:
expr: _col0
type: int
sort order: +
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col1
type: bigint
expr: _col2
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
expr: count(VALUE._col1)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: final
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
Stage: Stage-0
Move Operator
tables:
replace: true
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
set hive.map.aggr=false;
set hive.groupby.skewindata=false;
EXPLAIN extended
FROM INPUT
INSERT OVERWRITE TABLE dest1 SELECT INPUT.key, count(substr(INPUT.value,5)), count(distinct substr(INPUT.value,5)) GROUP BY INPUT.key;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-0 depends on stages: Stage-1
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Reduce Output Operator
key expressions:
expr: key
type: int
expr: substr(value, 5)
type: string
sort order: ++
Map-reduce partition columns:
expr: key
type: int
tag: -1
Needs Tagging: false
Path -> Alias:
hdfs://localhost:54310/user/hive/warehouse/input [input]
Path -> Partition:
hdfs://localhost:54310/user/hive/warehouse/input
Partition
base file name: input
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
properties:
bucket_count -1
columns key,value
columns.types int:string
file.inputformat org.apache.hadoop.mapred.TextInputFormat
file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
location hdfs://localhost:54310/user/hive/warehouse/input
name input
serialization.ddl struct input { i32 key, string value}
serialization.format 1
serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
transient_lastDdlTime 1310523947
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
properties:
bucket_count -1
columns key,value
columns.types int:string
file.inputformat org.apache.hadoop.mapred.TextInputFormat
file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
location hdfs://localhost:54310/user/hive/warehouse/input
name input
serialization.ddl struct input { i32 key, string value}
serialization.format 1
serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
transient_lastDdlTime 1310523947
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: input
name: input
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(KEY._col1:0._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: complete
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
directory: hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-50-38_510_6852880850328147221/-ext-10000
NumFilesPerFileSink: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
properties:
bucket_count -1
columns key,val1,val2
columns.types int:int:int
file.inputformat org.apache.hadoop.mapred.TextInputFormat
file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
location hdfs://localhost:54310/user/hive/warehouse/dest1
name dest1
serialization.ddl struct dest1 { i32 key, i32 val1, i32 val2}
serialization.format 1
serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
transient_lastDdlTime 1310523946
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
TotalFiles: 1
MultiFileSpray: false
Stage: Stage-0
Move Operator
tables:
replace: true
source: hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-50-38_510_6852880850328147221/-ext-10000
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
properties:
bucket_count -1
columns key,val1,val2
columns.types int:int:int
file.inputformat org.apache.hadoop.mapred.TextInputFormat
file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
location hdfs://localhost:54310/user/hive/warehouse/dest1
name dest1
serialization.ddl struct dest1 { i32 key, i32 val1, i32 val2}
serialization.format 1
serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
transient_lastDdlTime 1310523946
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
tmp directory: hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-50-38_510_6852880850328147221/-ext-10001
ABSTRACT SYNTAX TREE:
(TOK_QUERY
(TOK_FROM (TOK_TABREF INPUT))
(TOK_INSERT
(TOK_DESTINATION (TOK_TAB dest1))
(TOK_SELECT
(TOK_SELEXPR (. (TOK_TABLE_OR_COL INPUT) key))
(TOK_SELEXPR (TOK_FUNCTION count (TOK_FUNCTION substr (. (TOK_TABLE_OR_COL INPUT) value) 5)))
(TOK_SELEXPR (TOK_FUNCTIONDI count (TOK_FUNCTION substr (. (TOK_TABLE_OR_COL INPUT) value) 5)))
)
(TOK_GROUPBY (. (TOK_TABLE_OR_COL INPUT) key))
)
)
SemanticAnalyzer.genBodyPlan(QB qb, Operator input){
if (qbp.getAggregationExprsForClause(dest).size() != 0
|| getGroupByForClause(qbp, dest).size() > 0) { //如果有聚合函数或者有groupby，则执行下面的操作
//multiple distincts is not supported with skew in data
if (conf.getVar(HiveConf.ConfVars.HIVEGROUPBYSKEW)
.equalsIgnoreCase("true") &&
qbp.getDistinctFuncExprsForClause(dest).size() > 1) {
throw new SemanticException(ErrorMsg.UNSUPPORTED_MULTIPLE_DISTINCTS.
getMsg());
}
// insert a select operator here used by the ColumnPruner to reduce
// the data to shuffle
curr = insertSelectAllPlanForGroupBy(dest, curr); //生成一个SelectOperator，所有的字段都会选取，selectStar=true。
if (conf.getVar(HiveConf.ConfVars.HIVEMAPSIDEAGGREGATE)
.equalsIgnoreCase("true")) {
if (conf.getVar(HiveConf.ConfVars.HIVEGROUPBYSKEW)
.equalsIgnoreCase("false")) {
curr = genGroupByPlanMapAggr1MR(dest, qb, curr);
} else {
curr = genGroupByPlanMapAggr2MR(dest, qb, curr);
}
} else if (conf.getVar(HiveConf.ConfVars.HIVEGROUPBYSKEW)
.equalsIgnoreCase("true")) {
curr = genGroupByPlan2MR(dest, qb, curr);
} else {
curr = genGroupByPlan1MR(dest, qb, curr);
}
}
}
distince：
count.q.out
groupby11.q.out
groupby10.q.out
nullgroup4_multi_distinct.q.out
join18.q.out
groupby_bigdata.q.out
join18_multi_distinct.q.out
nullgroup4.q.out
auto_join18_multi_distinct.q.out
auto_join18.q.out
（1）map端部分聚合，数据无倾斜，一个MR生成。
genGroupByPlanMapAggr1MR，生成三个Operator：
（1.1）GroupByOperator：map-side partial aggregation，由genGroupByPlanMapGroupByOperator方法生成：
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，生成column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.HASH
outputColumnNames：groupby+Distinct+Aggregation
keys：groupby+Distinct
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（1.2）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby+distinct
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（1.3）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.MERGEPARTIAL
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（2）map端部分聚合，数据倾斜，两个MR生成。
genGroupByPlanMapAggr2MR：
（2.1）GroupByOperator：map-side partial aggregation，由genGroupByPlanMapGroupByOperator方法生成：
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，生成column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.HASH
outputColumnNames：groupby+Distinct+Aggregation
keys：groupby+Distinct
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（2.2）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby+distinct
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（2.3）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，生成column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.PARTIALS
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（2.4）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（2.5）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，需要做聚合的column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.FINAL
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（3）map端不部分聚合，数据倾斜，两个MR生成。
genGroupByPlan2MR：
（3.1）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby+distinct
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（3.2）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，生成column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.PARTIAL1
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（3.3）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（3.4）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，需要做聚合的column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.FINAL
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（4）map端不部分聚合，数据无倾斜，一个MR生成。
genGroupByPlan1MR：
（4.1）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby+distinct
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（4.2）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.COMPLETE
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
SemanticAnalyzer.genBodyPlan
optimizeMultiGroupBy (multi-group by with the same distinct)
groupby10.q groupby11.q
hive> select max(key) from src;
因为没有grouping keys，所以只有一个reducer。
2.2 如果有聚合函数或者groupby，做如下处理：
插入一个select operator，选取所有的字段，用于优化阶段ColumnPruner的优化
2.2.1 hive.map.aggr为true，默认是true，开启的，在map端做部分聚合
2.2.1.1 hive.groupby.skewindata为false，默认是关闭的，groupby的数据没有倾斜。
生成的operator是: GroupByOperator+ReduceSinkOperator+GroupByOperator。
GroupByOperator+ReduceSinkOperator用于在map端做操作，第一个GroupByOperator在map端先做部分聚合。第二个用于在reduce端做GroupBy操作
2.2.1.2 hive.groupby.skewindata为true
生成的operator是: GroupbyOperator+ReduceSinkOperator+GroupbyOperator+ReduceSinkOperator +GroupByOperator
GroupbyOperator+ReduceSinkOperator（第一个MapredTask的map阶段）
GroupbyOperator(第一个MapredTask的reduce阶段)
ReduceSinkOperator （第二个MapredTask的map阶段）
GroupByOperator（第二个MapredTask的reduce阶段）
2.2.2 hive.map.aggr为false
2.2.2.1 hive.groupby.skewindata为true
生成的operator是: ReduceSinkOperator+GroupbyOperator+ReduceSinkOperator +GroupByOperator
ReduceSinkOperator(第一个MapredTask的map阶段)
GroupbyOperator(第一个MapredTask的reduce阶段)
ReduceSinkOperator （第二个MapredTask的map阶段）
GroupByOperator（第二个MapredTask的reduce阶段）
2.2.2.2 hive.groupby.skewindata为false
生成的operator是: ReduceSinkOperator(map阶段运行)+GroupbyOperator（reduce阶段运行）
第一种情况：
set hive.map.aggr=false;
set hive.groupby.skewindata=false;
SemanticAnalyzer.genGroupByPlan1MR(){
（1）ReduceSinkOperator： It will put all Group By keys and the distinct field (if any) in the map-reduce sort key, and all other fields in the map-reduce value.
（2）GroupbyOperator：GroupByDesc.Mode.COMPLETE，Reducer: iterate/merge (mode = COMPLETE)
}
第二种情况：
set hive.map.aggr=true;
set hive.groupby.skewindata=false;
SemanticAnalyzer.genGroupByPlanMapAggr1MR(){
（1）GroupByOperator：GroupByDesc.Mode.HASH，The agggregation evaluation functions are as follows: Mapper: iterate/terminatePartial (mode = HASH)
（2）ReduceSinkOperator：Partitioning Key: grouping key。Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT
（3）GroupByOperator：GroupByDesc.Mode.MERGEPARTIAL，Reducer: iterate/terminate if DISTINCT merge/terminate if NO DISTINCT (mode = MERGEPARTIAL)
}
第三种情况：
set hive.map.aggr=false;
set hive.groupby.skewindata=true;
SemanticAnalyzer.genGroupByPlan2MR(){
（1）ReduceSinkOperator：Partitioning Key: random() if no DISTINCT grouping + distinct key if DISTINCT。Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT
（2）GroupbyOperator：GroupByDesc.Mode.PARTIAL1，Reducer: iterate/terminatePartial (mode = PARTIAL1)
（3）ReduceSinkOperator：Partitioning Key: grouping key。Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT
（4）GroupByOperator：GroupByDesc.Mode.FINAL，Reducer: merge/terminate (mode = FINAL)
}
第四种情况：
set hive.map.aggr=true;
set hive.groupby.skewindata=true;
SemanticAnalyzer.genGroupByPlanMapAggr2MR(){
（1）GroupbyOperator：GroupByDesc.Mode.HASH，Mapper: iterate/terminatePartial (mode = HASH)
（2）ReduceSinkOperator： Partitioning Key: random() if no DISTINCT grouping + distinct key if DISTINCT。 Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT。
（3）GroupbyOperator：GroupByDesc.Mode.PARTIALS， Reducer: iterate/terminatePartial if DISTINCT merge/terminatePartial if NO DISTINCT (mode = MERGEPARTIAL)
（4）ReduceSinkOperator：Partitioining Key: grouping key。Sorting Key: grouping key if no DISTINCT grouping + distinct key if DISTINCT
（5）GroupByOperator：GroupByDesc.Mode.FINAL，Reducer: merge/terminate (mode = FINAL)
}
ReduceSinkOperator的processOp(Object row, int tag)会根据相应的条件设置Key的hash值，如第四种情况的第一个ReduceSinkOperator：Partitioning Key: random() if no DISTINCT grouping + distinct key if DISTINCT，如果没有DISTINCT字段，那么在OutputCollector.collect前会设置当前Key的hash值为一个随机数，random = new Random(12345);。如果有DISTINCT字段，那么key的hash值跟grouping + distinct key有关。
GroupByOperator：
initializeOp(Configuration hconf)
processOp(Object row, int tag)
closeOp(boolean abort)
forward(ArrayList<Object> keys, AggregationBuffer[] aggs)
groupby10.q groupby11.q
set hive.map.aggr=false;
set hive.groupby.skewindata=false;
EXPLAIN
FROM INPUT
INSERT OVERWRITE TABLE dest1 SELECT INPUT.key, count(substr(INPUT.value,5)), count(distinct substr(INPUT.value,5)) GROUP BY INPUT.key;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-0 depends on stages: Stage-1
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator // insertSelectAllPlanForGroupBy
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Reduce Output Operator
key expressions:
expr: key
type: int
expr: substr(value, 5)
type: string
sort order: ++
Map-reduce partition columns:
expr: key
type: int
tag: -1
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(KEY._col1:0._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: complete
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
Stage: Stage-0
Move Operator
tables:
replace: true
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
set hive.map.aggr=true;
set hive.groupby.skewindata=false;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-0 depends on stages: Stage-1
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Group By Operator
aggregations:
expr: count(substr(value, 5))
expr: count(DISTINCT substr(value, 5))
bucketGroup: false
keys:
expr: key
type: int
expr: substr(value, 5)
type: string
mode: hash
outputColumnNames: _col0, _col1, _col2, _col3
Reduce Output Operator
key expressions:
expr: _col0
type: int
expr: _col1
type: string
sort order: ++
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col2
type: bigint
expr: _col3
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: mergepartial
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
Stage: Stage-0
Move Operator
tables:
replace: true
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
set hive.map.aggr=false;
set hive.groupby.skewindata=true;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-2 depends on stages: Stage-1
Stage-0 depends on stages: Stage-2
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Reduce Output Operator
key expressions:
expr: key
type: int
expr: substr(value, 5)
type: string
sort order: ++
Map-reduce partition columns:
expr: key
type: int
tag: -1
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(KEY._col1:0._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: partial1
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 0
table:
input format: org.apache.hadoop.mapred.SequenceFileInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
Stage: Stage-2
Map Reduce
Alias -> Map Operator Tree:
hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-48-26_387_7978992474997402829/-mr-10002
Reduce Output Operator
key expressions:
expr: _col0
type: int
sort order: +
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col1
type: bigint
expr: _col2
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
expr: count(VALUE._col1)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: final
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
Stage: Stage-0
Move Operator
tables:
replace: true
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
set hive.map.aggr=true;
set hive.groupby.skewindata=true;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-2 depends on stages: Stage-1
Stage-0 depends on stages: Stage-2
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Group By Operator
aggregations:
expr: count(substr(value, 5))
expr: count(DISTINCT substr(value, 5))
bucketGroup: false
keys:
expr: key
type: int
expr: substr(value, 5)
type: string
mode: hash
outputColumnNames: _col0, _col1, _col2, _col3
Reduce Output Operator
key expressions:
expr: _col0
type: int
expr: _col1
type: string
sort order: ++
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col2
type: bigint
expr: _col3
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: partials
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 0
table:
input format: org.apache.hadoop.mapred.SequenceFileInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
Stage: Stage-2
Map Reduce
Alias -> Map Operator Tree:
hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-49-25_899_4946067838822964610/-mr-10002
Reduce Output Operator
key expressions:
expr: _col0
type: int
sort order: +
Map-reduce partition columns:
expr: _col0
type: int
tag: -1
value expressions:
expr: _col1
type: bigint
expr: _col2
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
expr: count(VALUE._col1)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: final
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
Stage: Stage-0
Move Operator
tables:
replace: true
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
set hive.map.aggr=false;
set hive.groupby.skewindata=false;
EXPLAIN extended
FROM INPUT
INSERT OVERWRITE TABLE dest1 SELECT INPUT.key, count(substr(INPUT.value,5)), count(distinct substr(INPUT.value,5)) GROUP BY INPUT.key;
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-0 depends on stages: Stage-1
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
input
TableScan
alias: input
Select Operator
expressions:
expr: key
type: int
expr: value
type: string
outputColumnNames: key, value
Reduce Output Operator
key expressions:
expr: key
type: int
expr: substr(value, 5)
type: string
sort order: ++
Map-reduce partition columns:
expr: key
type: int
tag: -1
Needs Tagging: false
Path -> Alias:
hdfs://localhost:54310/user/hive/warehouse/input [input]
Path -> Partition:
hdfs://localhost:54310/user/hive/warehouse/input
Partition
base file name: input
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
properties:
bucket_count -1
columns key,value
columns.types int:string
file.inputformat org.apache.hadoop.mapred.TextInputFormat
file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
location hdfs://localhost:54310/user/hive/warehouse/input
name input
serialization.ddl struct input { i32 key, string value}
serialization.format 1
serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
transient_lastDdlTime 1310523947
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
properties:
bucket_count -1
columns key,value
columns.types int:string
file.inputformat org.apache.hadoop.mapred.TextInputFormat
file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
location hdfs://localhost:54310/user/hive/warehouse/input
name input
serialization.ddl struct input { i32 key, string value}
serialization.format 1
serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
transient_lastDdlTime 1310523947
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: input
name: input
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(KEY._col1:0._col0)
expr: count(DISTINCT KEY._col1:0._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: int
mode: complete
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: _col1
type: bigint
expr: _col2
type: bigint
outputColumnNames: _col0, _col1, _col2
Select Operator
expressions:
expr: _col0
type: int
expr: UDFToInteger(_col1)
type: int
expr: UDFToInteger(_col2)
type: int
outputColumnNames: _col0, _col1, _col2
File Output Operator
compressed: false
GlobalTableId: 1
directory: hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-50-38_510_6852880850328147221/-ext-10000
NumFilesPerFileSink: 1
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
properties:
bucket_count -1
columns key,val1,val2
columns.types int:int:int
file.inputformat org.apache.hadoop.mapred.TextInputFormat
file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
location hdfs://localhost:54310/user/hive/warehouse/dest1
name dest1
serialization.ddl struct dest1 { i32 key, i32 val1, i32 val2}
serialization.format 1
serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
transient_lastDdlTime 1310523946
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
TotalFiles: 1
MultiFileSpray: false
Stage: Stage-0
Move Operator
tables:
replace: true
source: hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-50-38_510_6852880850328147221/-ext-10000
table:
input format: org.apache.hadoop.mapred.TextInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
properties:
bucket_count -1
columns key,val1,val2
columns.types int:int:int
file.inputformat org.apache.hadoop.mapred.TextInputFormat
file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
location hdfs://localhost:54310/user/hive/warehouse/dest1
name dest1
serialization.ddl struct dest1 { i32 key, i32 val1, i32 val2}
serialization.format 1
serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
transient_lastDdlTime 1310523946
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
name: dest1
tmp directory: hdfs://localhost:54310/tmp/hive-tianzhao/hive_2011-07-15_21-50-38_510_6852880850328147221/-ext-10001
ABSTRACT SYNTAX TREE:
(TOK_QUERY
(TOK_FROM (TOK_TABREF INPUT))
(TOK_INSERT
(TOK_DESTINATION (TOK_TAB dest1))
(TOK_SELECT
(TOK_SELEXPR (. (TOK_TABLE_OR_COL INPUT) key))
(TOK_SELEXPR (TOK_FUNCTION count (TOK_FUNCTION substr (. (TOK_TABLE_OR_COL INPUT) value) 5)))
(TOK_SELEXPR (TOK_FUNCTIONDI count (TOK_FUNCTION substr (. (TOK_TABLE_OR_COL INPUT) value) 5)))
)
(TOK_GROUPBY (. (TOK_TABLE_OR_COL INPUT) key))
)
)
SemanticAnalyzer.genBodyPlan(QB qb, Operator input){
if (qbp.getAggregationExprsForClause(dest).size() != 0
|| getGroupByForClause(qbp, dest).size() > 0) { //如果有聚合函数或者有groupby，则执行下面的操作
//multiple distincts is not supported with skew in data
if (conf.getVar(HiveConf.ConfVars.HIVEGROUPBYSKEW)
.equalsIgnoreCase("true") &&
qbp.getDistinctFuncExprsForClause(dest).size() > 1) {
throw new SemanticException(ErrorMsg.UNSUPPORTED_MULTIPLE_DISTINCTS.
getMsg());
}
// insert a select operator here used by the ColumnPruner to reduce
// the data to shuffle
curr = insertSelectAllPlanForGroupBy(dest, curr); //生成一个SelectOperator，所有的字段都会选取，selectStar=true。
if (conf.getVar(HiveConf.ConfVars.HIVEMAPSIDEAGGREGATE)
.equalsIgnoreCase("true")) {
if (conf.getVar(HiveConf.ConfVars.HIVEGROUPBYSKEW)
.equalsIgnoreCase("false")) {
curr = genGroupByPlanMapAggr1MR(dest, qb, curr);
} else {
curr = genGroupByPlanMapAggr2MR(dest, qb, curr);
}
} else if (conf.getVar(HiveConf.ConfVars.HIVEGROUPBYSKEW)
.equalsIgnoreCase("true")) {
curr = genGroupByPlan2MR(dest, qb, curr);
} else {
curr = genGroupByPlan1MR(dest, qb, curr);
}
}
}
distince：
count.q.out
groupby11.q.out
groupby10.q.out
nullgroup4_multi_distinct.q.out
join18.q.out
groupby_bigdata.q.out
join18_multi_distinct.q.out
nullgroup4.q.out
auto_join18_multi_distinct.q.out
auto_join18.q.out
（1）map端部分聚合，数据无倾斜，一个MR生成。
genGroupByPlanMapAggr1MR，生成三个Operator：
（1.1）GroupByOperator：map-side partial aggregation，由genGroupByPlanMapGroupByOperator方法生成：
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，生成column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.HASH
outputColumnNames：groupby+Distinct+Aggregation
keys：groupby+Distinct
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（1.2）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby+distinct
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（1.3）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.MERGEPARTIAL
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（2）map端部分聚合，数据倾斜，两个MR生成。
genGroupByPlanMapAggr2MR：
（2.1）GroupByOperator：map-side partial aggregation，由genGroupByPlanMapGroupByOperator方法生成：
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，生成column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.HASH
outputColumnNames：groupby+Distinct+Aggregation
keys：groupby+Distinct
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（2.2）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby+distinct
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（2.3）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，生成column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.PARTIALS
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（2.4）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（2.5）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，需要做聚合的column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.FINAL
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（3）map端不部分聚合，数据倾斜，两个MR生成。
genGroupByPlan2MR：
（3.1）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby+distinct
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（3.2）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，生成column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.PARTIAL1
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（3.3）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（3.4）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入groupByKeys和outputColumnNames
处理聚合函数，getAggregationExprsForClause，生成AggregationDesc加入aggregations，需要做聚合的column加入outputColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.FINAL
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
（4）map端不部分聚合，数据无倾斜，一个MR生成。
genGroupByPlan1MR：
（4.1）ReduceSinkOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理select中的Distinct，getDistinctFuncExprsForClause，Distinct的column，加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public ReduceSinkDesc(java.util.ArrayList<ExprNodeDesc> keyCols,
int numDistributionKeys,
java.util.ArrayList<ExprNodeDesc> valueCols,
java.util.ArrayList<java.lang.String> outputKeyColumnNames,
List<List<Integer>> distinctColumnIndices,
java.util.ArrayList<java.lang.String> outputValueColumnNames, int tag,
java.util.ArrayList<ExprNodeDesc> partitionCols, int numReducers,
final TableDesc keySerializeInfo, final TableDesc valueSerializeInfo) {
this.keyCols = keyCols; // 为reduceKeys，groupby+distinct
this.numDistributionKeys = numDistributionKeys; // grpByExprs.size()
this.valueCols = valueCols; //reduceValues，聚合函数
this.outputKeyColumnNames = outputKeyColumnNames; //outputKeyColumnNames
this.outputValueColumnNames = outputValueColumnNames; //outputValueColumnNames
this.tag = tag; // -1
this.numReducers = numReducers; // 一般都是-1
this.partitionCols = partitionCols; // groupby
this.keySerializeInfo = keySerializeInfo;
this.valueSerializeInfo = valueSerializeInfo;
this.distinctColumnIndices = distinctColumnIndices;
}
（4.2）GroupByOperator
处理groupby子句，getGroupByForClause，groupby的column加入reduceKeys和outputKeyColumnNames
处理聚合函数，getAggregationExprsForClause，需要做聚合的column加入reduceValues和outputValueColumnNames
public GroupByDesc(
final Mode mode,
final java.util.ArrayList<java.lang.String> outputColumnNames,
final java.util.ArrayList<ExprNodeDesc> keys,
final java.util.ArrayList<org.apache.hadoop.hive.ql.plan.AggregationDesc> aggregators,
final boolean groupKeyNotReductionKey,float groupByMemoryUsage, float memoryThreshold) {
this(mode, outputColumnNames, keys, aggregators, groupKeyNotReductionKey,
false, groupByMemoryUsage, memoryThreshold);
}
mode：GroupByDesc.Mode.COMPLETE
outputColumnNames：groupby+Aggregation
keys：groupby
aggregators：Aggregation
groupKeyNotReductionKey：false
groupByMemoryUsage：默认为0.5
memoryThreshold：默认为0.9
SemanticAnalyzer.genBodyPlan
optimizeMultiGroupBy (multi-group by with the same distinct)
groupby10.q groupby11.q
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发表评论
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hive rename table name
2013-09-18 14:28 2594hive rename tablename hive re ... -
hive的distribute by如何partition long型的数据
2013-08-20 10:15 2470有用户问：hive的distribute by分桶是怎么分 ... -
hive like vs rlike vs regexp
2013-04-11 18:53 11208like vs rlike vs regexp r ... -
hive sql where条件很简单，但是太多
2012-07-18 15:51 8734insert overwrite table aaaa ... -
insert into时(string->bigint)自动类型转换
2012-06-14 12:30 8277原表src： hive> desc src; ... -
通过复合结构来优化udf的调用
2012-05-11 14:07 1206select split("accba&quo ... -
RegexSerDe
2012-03-14 09:58 1544官方示例在： https://cwiki.apache.or ... -
Hive 的 OutputCommitter
2012-01-30 19:44 1813Hive 的 OutputCommitter publi ... -
hive LATERAL VIEW 行转列
2011-11-09 14:49 5442drop table lateralview; create ... -
hive complex type
2011-11-08 19:56 1360数据： 1,100|3,20|2,70|5,100 建表： ... -
hive转义字符
2011-10-25 16:41 6238CREATE TABLE escape (id STRING, ... -
hive 两个不同类型的columns进行比较
2011-09-19 13:46 3032select case when "ab1234&q ... -
lateral view
2011-09-18 04:04 0lateral view与udtf相关 -
udf 中获得 FileSystem
2011-09-14 10:28 0在udf中获得FileSystem，需要获得知道fs.defa ... -
hive union mapjoin
2011-09-09 16:29 0union union.q union2.q ... -
hive eclipse
2011-09-08 17:42 0eclipse-templates$ vi .classpat ... -
hive join filter
2011-09-07 23:05 0join16.q.out hive.optimize.ppd ... -
hive limit
2011-09-07 21:02 0limit 关键字： input4_limit.q.out ... -
hive convertMapJoin MapJoinProcessor
2011-09-06 21:17 0join25.q join26 ... -
hive hive.merge.mapfiles hive.merge.mapredfiles
2011-09-06 19:14 0HiveConf： HIVEMERGEMAPFILES ...
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