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https://issues.apache.org/jira/browse/HIVE-9500?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14302595#comment-14302595
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Lefty Leverenz commented on HIVE-9500:
--------------------------------------

Doc note:  "hive.serialization.extend.nesting.levels" and 
"hive.serialization.extend.additional.nesting.levels" are SerDe properties, not 
HiveConf properties.  Their documentation should go in the Hive Types wikidoc, 
either in a new section for structs or in the existing "Complex Types" section, 
and perhaps in the DDL wikidoc.  (One of these days we should add a section on 
SerDe properties to the Hive SerDes wikidoc.)

* [Hive Data Types -- Complex Types | 
https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Types#LanguageManualTypes-ComplexTypes]
* [DDL -- Create Table -- Row Format, Storage Format, and SerDe | 
https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-RowFormat,StorageFormat,andSerDe]
* [DDL -- Alter Table -- Add SerDe Properties | 
https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-AddSerDeProperties]
* [Hive SerDes | https://cwiki.apache.org/confluence/display/Hive/SerDe]

Javadoc descriptions for the properties are in 
serde/src/java/org/apache/hadoop/hive/serde2/SerDeParameters.java:

{code}
+       /**
+        * To be backward-compatible, initialize the first 3 separators to 
+   * be the given values. Default number of separators to be 8; If only
+   * hive.serialization.extend.nesting.levels is set, extend the number of
+   * separators to be 24; if 
hive.serialization.extend.additional.nesting.levels
+   * is set, extend the number of separators to 154.
+        * @param tbl
+        */
{code}

Editorial review:  Please align the asterisks and change the first semicolon to 
a period ("to be 8; If only...").

> Support nested structs over 24 levels.
> --------------------------------------
>
>                 Key: HIVE-9500
>                 URL: https://issues.apache.org/jira/browse/HIVE-9500
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Aihua Xu
>            Assignee: Aihua Xu
>              Labels: SerDe
>             Fix For: 1.2.0
>
>         Attachments: HIVE-9500.1.patch
>
>
> Customer has deeply nested avro structure and is receiving the following 
> error when performing queries.
> 15/01/09 20:59:29 ERROR ql.Driver: FAILED: SemanticException 
> org.apache.hadoop.hive.serde2.SerDeException: Number of levels of nesting 
> supported for LazySimpleSerde is 23 Unable to work with level 24
> Currently we support up to 24 levels of nested structs when 
> hive.serialization.extend.nesting.levels is set to true, while the customers 
> have the requirement to support more than that. 
> It would be better to make the supported levels configurable or completely 
> removed (i.e., we can support any number of levels). 



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