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Posted to issues@hive.apache.org by "Thai Bui (JIRA)" <ji...@apache.org> on 2018/12/28 08:53:00 UTC
[jira] [Updated] (HIVE-21074) Hive bucketed table query pruning
does not work for IS NOT NULL condition
[ https://issues.apache.org/jira/browse/HIVE-21074?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Thai Bui updated HIVE-21074:
----------------------------
Component/s: (was: Query Planning)
Logical Optimizer
> Hive bucketed table query pruning does not work for IS NOT NULL condition
> -------------------------------------------------------------------------
>
> Key: HIVE-21074
> URL: https://issues.apache.org/jira/browse/HIVE-21074
> Project: Hive
> Issue Type: Bug
> Components: Logical Optimizer
> Affects Versions: 3.0.0, 3.1.0, 3.1.1
> Reporter: Thai Bui
> Assignee: Thai Bui
> Priority: Minor
>
> The current version of bucket pruning skips all the predicates when it detects that one of the predicates is a compound type (e.g. NOT(IS_NULL) ) when evaluating AND logical operators.
> This logic is faulty since as long as one of the AND operators is a bucketed column (_col_ = *literal*), the *literal* value of that _col_ should be considered in the bucket pruning optimization no matter what. For example:
> SELECT * FROM tbl WHERE bucketed_col = 1 AND (some_compound_expr)
> Then the the value '*1'* should be considered for pruning in the query plan. This limitation has manifested into a simpler case where a table that I am trying to optimized using bucketing technique is not effective when IS NOT NULL is used. Since IS NOT NULL is parsed into NOT(IS_NULL) (a compound expression), the pruning phase is completed skipped causing unnecessary tasks to be spawned. For instance:
> SELECT * FROM tbl WHERE bucketed_col = 1 AND some_other_col IS NOT NULL
> Will not trigger bucket pruning logic and perform a full table scan.
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