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Posted to issues@hive.apache.org by "Wei Yan (JIRA)" <ji...@apache.org> on 2016/09/16 16:49:20 UTC
[jira] [Assigned] (HIVE-14630) Enable PPD for AND conditions when
CBO is disabled
[ https://issues.apache.org/jira/browse/HIVE-14630?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Wei Yan reassigned HIVE-14630:
------------------------------
Assignee: Wei Yan
> Enable PPD for AND conditions when CBO is disabled
> --------------------------------------------------
>
> Key: HIVE-14630
> URL: https://issues.apache.org/jira/browse/HIVE-14630
> Project: Hive
> Issue Type: Bug
> Components: Logical Optimizer
> Affects Versions: 2.2.0
> Reporter: Chao Sun
> Assignee: Wei Yan
>
> 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:
> {code}
> SELECT a.id FROM a JOIN b
> ON a.id = b.id
> WHERE a.datestr >= '2016-08-20'
> AND rand() > 0.5
> {code}
> For this query, the plan looks like the following:
> {code}
> 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
> {code}
> 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.
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