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From "Jesus Camacho Rodriguez (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-11634) Support partition pruning for IN(STRUCT(partcol, nonpartcol..)...)
Date Thu, 01 Oct 2015 09:39:26 GMT

    [ https://issues.apache.org/jira/browse/HIVE-11634?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14939580#comment-14939580
] 

Jesus Camacho Rodriguez commented on HIVE-11634:
------------------------------------------------

1. That's what I thought, no problem.
2. OK, this case should be solved or studied as part of this JIRA.
3. That's fine; we can create a new JIRA case for that. But maybe I would remove then the
changes in PcrExprProcFactory.java and I would follow-up in the new JIRA, as that code is
not working as expected. What do you think?
4. Maybe I didn't explain it properly. The idea is that you would only prepend non-partition
columns, and without clustering them, but iff the NDV in the IN clause is reduced. In any
case, we can create a new JIRA for this too, and maybe assign it to me? As I see it, the modification
to the original optimization that you have just created should not be too complicated.

> Support partition pruning for IN(STRUCT(partcol, nonpartcol..)...)
> ------------------------------------------------------------------
>
>                 Key: HIVE-11634
>                 URL: https://issues.apache.org/jira/browse/HIVE-11634
>             Project: Hive
>          Issue Type: Bug
>          Components: CBO
>            Reporter: Hari Sankar Sivarama Subramaniyan
>            Assignee: Hari Sankar Sivarama Subramaniyan
>         Attachments: HIVE-11634.1.patch, HIVE-11634.2.patch, HIVE-11634.3.patch, HIVE-11634.4.patch,
HIVE-11634.5.patch, HIVE-11634.6.patch, HIVE-11634.7.patch, HIVE-11634.8.patch, HIVE-11634.9.patch,
HIVE-11634.91.patch, HIVE-11634.92.patch, HIVE-11634.93.patch, HIVE-11634.94.patch, HIVE-11634.95.patch,
HIVE-11634.96.patch, HIVE-11634.97.patch
>
>
> Currently, we do not support partition pruning for the following scenario
> {code}
> create table pcr_t1 (key int, value string) partitioned by (ds string);
> insert overwrite table pcr_t1 partition (ds='2000-04-08') select * from src where key
< 20 order by key;
> insert overwrite table pcr_t1 partition (ds='2000-04-09') select * from src where key
< 20 order by key;
> insert overwrite table pcr_t1 partition (ds='2000-04-10') select * from src where key
< 20 order by key;
> explain extended select ds from pcr_t1 where struct(ds, key) in (struct('2000-04-08',1),
struct('2000-04-09',2));
> {code}
> If we run the above query, we see that all the partitions of table pcr_t1 are present
in the filter predicate where as we can prune  partition (ds='2000-04-10'). 
> The optimization is to rewrite the above query into the following.
> {code}
> explain extended select ds from pcr_t1 where  (struct(ds)) IN (struct('2000-04-08'),
struct('2000-04-09')) and  struct(ds, key) in (struct('2000-04-08',1), struct('2000-04-09',2));
> {code}
> The predicate (struct(ds)) IN (struct('2000-04-08'), struct('2000-04-09'))  is used by
partition pruner to prune the columns which otherwise will not be pruned.
> This is an extension of the idea presented in HIVE-11573.



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