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From "Alexander Kolbasov (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-19253) HMS ignores tableType property for external tables
Date Thu, 16 Aug 2018 16:42:00 GMT

    [ https://issues.apache.org/jira/browse/HIVE-19253?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16582808#comment-16582808
] 

Alexander Kolbasov commented on HIVE-19253:
-------------------------------------------

The patch does two things:

# If table type is specified as EXTERNAL, table becomes external whether it has EXTERNAL property
or not
# If tableType in a stored table is set to EXTERNAL table is treated as external whether it
has EXTERNAL property or not.

The first part only affects new tables. The second part affects existing tables as well, so
there is some risk of a table suddenly changing from managed to external. 

[~alangates] [~vihangk1] What do you think about this? Should I limit the patch to only affect
new tables?

> HMS ignores tableType property for external tables
> --------------------------------------------------
>
>                 Key: HIVE-19253
>                 URL: https://issues.apache.org/jira/browse/HIVE-19253
>             Project: Hive
>          Issue Type: Bug
>          Components: Metastore
>    Affects Versions: 3.0.0, 3.1.0, 4.0.0
>            Reporter: Alexander Kolbasov
>            Assignee: Alexander Kolbasov
>            Priority: Major
>              Labels: newbie
>         Attachments: HIVE-19253.01.patch, HIVE-19253.02.patch, HIVE-19253.03.patch, HIVE-19253.03.patch,
HIVE-19253.04.patch, HIVE-19253.05.patch
>
>
> When someone creates a table using Thrift API they may think that setting tableType to
{{EXTERNAL_TABLE}} creates an external table. And boom - their table is gone later because
HMS will silently change it to managed table.
> here is the offending code:
> {code:java}
>   private MTable convertToMTable(Table tbl) throws InvalidObjectException,
>       MetaException {
>     ...
>     // If the table has property EXTERNAL set, update table type
>     // accordingly
>     String tableType = tbl.getTableType();
>     boolean isExternal = Boolean.parseBoolean(tbl.getParameters().get("EXTERNAL"));
>     if (TableType.MANAGED_TABLE.toString().equals(tableType)) {
>       if (isExternal) {
>         tableType = TableType.EXTERNAL_TABLE.toString();
>       }
>     }
>     if (TableType.EXTERNAL_TABLE.toString().equals(tableType)) {
>       if (!isExternal) { // Here!
>         tableType = TableType.MANAGED_TABLE.toString();
>       }
>     }
> {code}
> So if the EXTERNAL parameter is not set, table type is changed to managed even if it
was external in the first place - which is wrong.
> More over, in other places code looks at the table property to decide table type and
some places look at parameter. HMS should really make its mind which one to use.



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