Details
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Bug
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Status: Open
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Major
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Resolution: Unresolved
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2.2.0
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None
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None
Description
Currently the PPD optimization seems not be able to handle AND conditions very well, when CBO is not used. To illustrate with a example:
Table a:
| col | type | part_col? |
|---|---|---|
| id | int | no |
| datestr | string | yes |
Table b:
| col | type | part_col? |
|---|---|---|
| id | int | no |
And the following query:
SELECT a.id FROM a JOIN b
ON a.id = b.id
WHERE a.datestr >= '2016-08-20'
AND rand() > 0.5
For this query, the plan looks like the following:
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-0 depends on stages: Stage-1
STAGE PLANS:
Stage: Stage-1
Map Reduce
Map Operator Tree:
TableScan
alias: a
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
Filter Operator
predicate: id is not null (type: boolean)
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
Reduce Output Operator
key expressions: id (type: bigint)
sort order: +
Map-reduce partition columns: id (type: bigint)
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
value expressions: datestr (type: string)
TableScan
alias: b
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
Filter Operator
predicate: id is not null (type: boolean)
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
Reduce Output Operator
key expressions: id (type: bigint)
sort order: +
Map-reduce partition columns: id (type: bigint)
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
Reduce Operator Tree:
Join Operator
condition map:
Inner Join 0 to 1
keys:
0 id (type: bigint)
1 id (type: bigint)
outputColumnNames: _col0, _col2
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
Filter Operator
predicate: ((_col2 >= '2016-08-20') and (rand() > 0.5)) (type: boolean)
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
Select Operator
expressions: _col0 (type: bigint)
outputColumnNames: _col0
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
File Output Operator
compressed: false
Statistics: Num rows: 1 Data size: 0 Basic stats: PARTIAL Column stats: NONE
table:
input format: org.apache.hadoop.mapred.SequenceFileInputFormat
output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
Stage: Stage-0
Fetch Operator
limit: -1
Processor Tree:
ListSink
Note that the predicate a.datestr >= '2016-08-20' is not pushed down, since rand() is not deterministic and thus the whole predicate is not eligible.
Attachments
Issue Links
- duplicates
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HIVE-14661 Hive should extract deterministic conditions from where clause and use them for partition pruning
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- Open
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- is related to
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- Open
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