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From "Remus Rusanu (JIRA)" <>
Subject [jira] [Commented] (HIVE-16667) PostgreSQL metastore handling of CLOB types for COLUMNS_V2.TYPE_NAME and other field is incorrect
Date Tue, 23 May 2017 07:29:04 GMT


Remus Rusanu commented on HIVE-16667:

I don't see how your patch will address the problem of mixing  pre v3.0 upgraded tables and
post v.30 created one. the new ones will store the {{TYPE_NAME}} as a LOB handle, while the
upgraded ones will have the inlined string value.

Can we explore instead reverting the column type mapping to {{VARCHAR}} in the package.jdo,
(or {{LONGVARCHAR}} if need be) instead of {{CLOB}}? Keep the metastore upgrade scripts, change
the underlying storage tyopes to respective large types, but have JDO map them to String,
not Clob. On my testing with PG, this works correctly on all cases I tested (my repro, your
large serde DDL from HIVE-12274), and should handle upgrade correctly. But I did not test
this with other metastore engines, Oracle, MySQL etc.

> PostgreSQL metastore handling of CLOB types for COLUMNS_V2.TYPE_NAME and other field
is incorrect
> -------------------------------------------------------------------------------------------------
>                 Key: HIVE-16667
>                 URL:
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Remus Rusanu
>            Assignee: Naveen Gangam
>         Attachments: HIVE-16667.patch, HiveCLIOutput.txt, PostgresDBOutput.txt
> The CLOB JDO type introduced with HIVE-12274 does not work correctly with PostgreSQL.
The value is written out-of-band and the LOB handle is written,as an INT, into the table.
SELECTs return the INT value, which should had been read via the {{lo_get}} PG built-in, and
then cast into string.
> Furthermore, the behavior is different between fields upgraded from earlier metastore
versions (they retain their string storage) vs. values inserted after the upgrade (inserted
as LOB roots).
> Teh code in {{MetasoreDirectSql.getPartitionsFromPartitionIds/extractSqlClob}} expects
the underlying JDO/Datanucleus to map the column to a {{Clob}} but that does not happen, the
value is a Java String containing the int which is the LOB root saved by PG.
> This manifests at runtime with errors like:
> {code}
> hive> select * from srcpart;
> Failed with exception Error:
type expected at the position 0 of '24030:24031' but '24030' is found.
> {code}
> the 24030:24031 should be 'string:string'.
> repro:
> {code}
> CREATE TABLE srcpart (key STRING COMMENT 'default', value STRING COMMENT 'default') PARTITIONED
PARTITION (ds="2008-04-09", hr="11");
> select * from srcpart;
> {code}
> I did not see the issue being hit by non-partitioned/textfile tables, but that is just
the luck of the path taken by the code. Inspection of my PG metastore shows all the CLOB fields
suffering from this issue.

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