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https://issues.apache.org/jira/browse/HIVE-11752?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15145853#comment-15145853
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Lefty Leverenz commented on HIVE-11752:
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Doc note: This adds *hive.optimize.cte.materialize.threshold* to HiveConf.java
for release 2.1.0, so it should be mentioned in the Common Table Expression
wikidoc and documented in Configuration Properties.
* [Common Table Expression |
https://cwiki.apache.org/confluence/display/Hive/Common+Table+Expression]
* [Configuration Properties -- Query and DDL Execution |
https://cwiki.apache.org/confluence/display/Hive/Configuration+Properties#ConfigurationProperties-QueryandDDLExecution]
> 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
> Labels: TODOC2.1
> Fix For: 2.1.0
>
> Attachments: HIVE-11752.03.patch, HIVE-11752.04.patch,
> HIVE-11752.05.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).
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