[
https://issues.apache.org/jira/browse/HIVE-11752?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15127939#comment-15127939
]
Jesus Camacho Rodriguez commented on HIVE-11752:
------------------------------------------------
[~navis], thanks to you, the patch was almost ready (modulo some
fixes/testing). It would be indeed a great addition.
I guess there are two reasons why views need special treatment.
First, CTE within view should not be materialized. Thus, I introduced a flag
that disables CTE materialization if we are parsing a view creation/alter
statement.
Secondly, counting CTE references within views is a bit tricky (code is a bit
convoluted). The current patch skips views for counting purposes, treating them
simply as tables. We can address this issue in a follow-up JIRA.
> Pre-materializing complex CTE queries
> -------------------------------------
>
> Key: HIVE-11752
> URL: https://issues.apache.org/jira/browse/HIVE-11752
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Affects Versions: 2.1.0
> Reporter: Navis
> Assignee: Jesus Camacho Rodriguez
> Priority: Minor
> Attachments: HIVE-11752.03.patch, HIVE-11752.04.patch,
> HIVE-11752.1.patch.txt, HIVE-11752.2.patch.txt
>
>
> Currently, hive regards CTE clauses as a simple alias to the query block,
> which makes redundant works if it's used multiple times in a query. This
> introduces a reference threshold for pre-materializing the CTE clause as a
> volatile table (which is not exists in any form of metastore and just
> accessible from QB).
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
