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Posted to issues@spark.apache.org by "Chao Sun (Jira)" <ji...@apache.org> on 2020/10/31 19:14:00 UTC
[jira] [Updated] (SPARK-33311) Improve semantics for REFRESH TABLE
[ https://issues.apache.org/jira/browse/SPARK-33311?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chao Sun updated SPARK-33311:
-----------------------------
Description:
Currently, the semantics for {{REFRESH TABLE t}} is not well defined for view (let's say {{view}}) that reference the table {{t}}:
1. If {{view}} is cached, the behavior is not well-defined. Should Spark invalidate the cache (current behavior) or recache it?
2. If {{view}} is a temporary view, currently refreshing {{t}} does not refresh {{view}} since it will just reuse the logical plan stored in the session catalog. This could lead to incorrect results.
I think we should clear define and document the behavior here, so that users won't get confused.
was:
Currently, the semantics for {{REFRESH TABLE t}} is not well defined for view (let's say {{view}}) that reference the table {{t}}:
1. If {{view}} is cached, the behavior is not well-defined. Should Spark invalidate the cache (current behavior) or recache it?
2. If {{view}} is a temporary view, currently refreshing {{t}} does not refresh {{view}} since it will just reuse the logical plan defined in the session catalog. This could lead to incorrect results.
I think we should clear define and document the behavior here, so that users won't get confused.
> Improve semantics for REFRESH TABLE
> -----------------------------------
>
> Key: SPARK-33311
> URL: https://issues.apache.org/jira/browse/SPARK-33311
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 3.0.1
> Reporter: Chao Sun
> Priority: Major
>
> Currently, the semantics for {{REFRESH TABLE t}} is not well defined for view (let's say {{view}}) that reference the table {{t}}:
> 1. If {{view}} is cached, the behavior is not well-defined. Should Spark invalidate the cache (current behavior) or recache it?
> 2. If {{view}} is a temporary view, currently refreshing {{t}} does not refresh {{view}} since it will just reuse the logical plan stored in the session catalog. This could lead to incorrect results.
> I think we should clear define and document the behavior here, so that users won't get confused.
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