[jira] [Commented] (IMPALA-9499) Display support for all complex types in a SELECT * query

["Gabor Kaszab (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IMPALA-9499?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17073614#comment-17073614 ] 

Gabor Kaszab commented on IMPALA-9499:
--------------------------------------

I found this in one of the old design docs for complex types:
"We will not perform automatic serialization of complex types to protect users against inadvertently writing a query that is very expensive due to excessive serialization. Users must explicitly wrap complex column references in the top-level select list with a serialization function such as ToJson(). For example, the following queries are illegal:
SELECT orders FROM customers
SELECT * FROM customers"

I tend to agree with the select * part. We might want to leave the logic as it is and omit the complex types for a select *. Other solution is to somehow signal to the user that there was something we omited so you don't see the whole table. Or we can fill the complex typed  columns with some dummy string value.

> Display support for all complex types in a SELECT * query
> ---------------------------------------------------------
>
>                 Key: IMPALA-9499
>                 URL: https://issues.apache.org/jira/browse/IMPALA-9499
>             Project: IMPALA
>          Issue Type: New Feature
>            Reporter: Gabor Kaszab
>            Assignee: Adam Tamas
>            Priority: Major
>              Labels: complextype
>
> Covers all complex types (Struct, Array, Map) for both Parquet and ORC file formats.



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