[jira] [Commented] (HIVE-8485) HMS on Oracle incompatibility

["Andy Jefferson (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-8485?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14237100#comment-14237100 ] 

Andy Jefferson commented on HIVE-8485:
--------------------------------------

DataNucleus has no "problem" with nulls or empty strings in that it issues SQL to a datastore and the store replies, and DN also provides the ability for the user to decide how nulls are stored in Oracle via property "datanucleus.rdbms.persistEmptyStringAsNull". Can't see how whatever your problem is (table missing?!) relates to DataNucleus software.

> HMS on Oracle incompatibility
> -----------------------------
>
>                 Key: HIVE-8485
>                 URL: https://issues.apache.org/jira/browse/HIVE-8485
>             Project: Hive
>          Issue Type: Bug
>          Components: Metastore
>         Environment: Oracle as metastore DB
>            Reporter: Ryan Pridgeon
>
> Oracle does not distinguish between empty strings and NULL,which proves problematic for DataNucleus.
> In the event a user creates a table with some property stored as an empty string the table will no longer be accessible.
> i.e. TBLPROPERTIES ('serialization.null.format'='')
> If they try to select, describe, drop, etc the client prints the following exception.
> ERROR ql.Driver: FAILED: SemanticException [Error 10001]: Table not found <table name>
> The work around for this was to go into the hive metastore on the Oracle database and replace NULL with some other string. Users could then drop the tables or alter their data to use the new null format they just set.



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