这将取决于你的蜂巢版本如何优化它。在我当前的版本(1.1.0)中,Hive能够指向特定的分区,而无需扫描顶部分区
下面是一个快速演示。
create table mydb.partition_test
(id string)
partitioned by (city string, village string);
INSERT OVERWRITE TABLE mydb.partition_test PARTITION (city,village)
select * from (
select '1', 'city1', 'village1'
union all
select '1', 'city1', 'village2'
union all
select '1', 'city1', 'village3'
union all
select '1', 'city2', 'village5'
union all
select '1', 'city2', 'village6'
) t;
explain select * from mydb.partition_test where village='village5';
STAGE DEPENDENCIES:
Stage-0 is a root stage
STAGE PLANS:
Stage: Stage-0
Fetch Operator
limit: -1
Processor Tree:
TableScan
alias: partition_test
filterExpr: (village = 'village5') (type: boolean)
Statistics: Num rows: 1 Data size: 1 Basic stats: COMPLETE Column stats: PARTIAL
Select Operator
expressions: id (type: string), city (type: string), 'village5' (type: string)
outputColumnNames: _col0, _col1, _col2
Statistics: Num rows: 1 Data size: 1 Basic stats: COMPLETE Column stats: PARTIAL
ListSink
