[
https://issues.apache.org/jira/browse/HIVE-5771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14028582#comment-14028582
]
Ashutosh Chauhan commented on HIVE-5771:
----------------------------------------
Looked further into it.
* Optimization HIVE_MAP_GROUPBY_SORT is no longer being effective , thus plans
for groupby_sort_1.q,groupby_sort_skew_1.q are changed.
* Queries which have not in where clause like select * from T where c1 not in
(select c2 from T) queries are resulting in wrong results. So, results of
subquery_multiinsert.q,subquery_notin.q looks incorrect.
* Changes for annotate_stats_filter.q looks correct since after optimization
of where !false we get optimization of select * from T which results in
FetchTask only plan.
* Warning for cross-product for join cases is fine and can be ignored.
* smb_mapjoin_25.q needs to be looked into.
> Constant propagation optimizer for Hive
> ---------------------------------------
>
> Key: HIVE-5771
> URL: https://issues.apache.org/jira/browse/HIVE-5771
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Ted Xu
> Assignee: Ted Xu
> Attachments: HIVE-5771.1.patch, HIVE-5771.10.patch,
> HIVE-5771.11.patch, HIVE-5771.2.patch, HIVE-5771.3.patch, HIVE-5771.4.patch,
> HIVE-5771.5.patch, HIVE-5771.6.patch, HIVE-5771.7.patch, HIVE-5771.8.patch,
> HIVE-5771.9.patch, HIVE-5771.patch, HIVE-5771.patch.javaonly
>
>
> Currently there is no constant folding/propagation optimizer, all expressions
> are evaluated at runtime.
> HIVE-2470 did a great job on evaluating constants on UDF initializing phase,
> however, it is still a runtime evaluation and it doesn't propagate constants
> from a subquery to outside.
> It may reduce I/O and accelerate process if we introduce such an optimizer.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
