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https://issues.apache.org/jira/browse/HIVE-21897?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16868949#comment-16868949
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Mithun Radhakrishnan commented on HIVE-21897:
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bq. Mithun Radhakrishnan just for sure I've inserted two rows, one with dt=1,
one with dt=2, and checked the files in HDFS. They are both ORC files.
Pardon me, but this does not sound right. How exactly did you insert values
into {{dt=1}} and {{dt=2}}? At what point did you write to each of the
partitions? If you {{INSERT OVERWRITE}} *after* the partitions were created,
then I can understand how you see what you see. But, consider this sequence:
{code:sql}
-- Create the table.
CREATE TABLE foobar ( foo STRING, bar STRING ) PARTITIONED BY (dt STRING)
STORED AS TEXTFILE;
-- 1.
INSERT OVERWRITE TABLE foobar PARTITION( dt='1' ) VALUES ( "foo1", "value1" );
-- SerDe == LazySimpleSerDe.
-- Describe the partition, to confirm.
DESC FORMATTED TABLE foobar PARTITION (dt='1');
-- Alter format.
ALTER TABLE foobar SET FILEFORMAT ORCFILE; -- (No CASCADE)
-- 2.
INSERT OVERWRITE TABLE foobar PARTITION( dt='2' ) VALUES ( "foo2", "value2" );
-- SerDe == OrcSerDe.
-- Describe the partition, to confirm.
DESC FORMATTED TABLE foobar PARTITION (dt='2');
{code}
In this case, if {{dt='1'}} doesn't retain its SerDe setting, it will be
rendered unreadable after the table-format is changed. Please correct me if I'm
wrong.
> Setting serde / serde properties for partitions
> -----------------------------------------------
>
> Key: HIVE-21897
> URL: https://issues.apache.org/jira/browse/HIVE-21897
> Project: Hive
> Issue Type: Bug
> Components: Hive
> Affects Versions: 3.1.1
> Reporter: Miklos Gergely
> Assignee: Miklos Gergely
> Priority: Major
> Fix For: 4.0.0
>
>
> According to
> [https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-AddSerDeProperties]
> the SerDe and the SerDe properties can be set for a partition too, so
>
> {code:java}
> ALTERT TABLE table PARTITION (partition_col='partition_value') SET SERDE
> 'serde.class.name';{code}
> Is a valid statement. In fact it is not rejected, but it is not doing
> anything at all. The execution is successful, everything remains the same.
> The same is true for setting the serde properties:
> {code:java}
> ALTER TABLE table PARTITION (partition_col='partition_value') SET
> SERDEPROPERTIES ('property_name'='property_value');{code}
> is also a valid statement, and not doing anything.
> I suggest to modify the parser, and reject these statements. SerDe is for a
> table, and not for a partition.
>
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