[jira] [Commented] (HIVE-15995) Syncing metastore table with serde schema

["Adam Szita (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-15995?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16387965#comment-16387965 ] 

Adam Szita commented on HIVE-15995:
-----------------------------------

[~vihangk1] thanks for taking a look!

Agree with the cascade proposal, I've added this option in my new patch ([^HIVE-15995.4.patch])

In the q test what I do is basically update the Avro schema and then remove the setting avro.schema.url/literal. After removal HMS will either have the old schema when I call describe, or it will have the new schema, if I also called {{update columns}} before removing the setting. That's what the q tests are based on.

On the test failures, I'll see what result I'll get after this latest change and will triage it.

> Syncing metastore table with serde schema
> -----------------------------------------
>
>                 Key: HIVE-15995
>                 URL: https://issues.apache.org/jira/browse/HIVE-15995
>             Project: Hive
>          Issue Type: Bug
>          Components: Metastore
>    Affects Versions: 1.2.1, 2.1.0, 3.0.0
>            Reporter: Michal Ferlinski
>            Assignee: Adam Szita
>            Priority: Major
>         Attachments: HIVE-15995.1.patch, HIVE-15995.2.patch, HIVE-15995.3.patch, HIVE-15995.4.patch, HIVE-15995.patch, cx1.avsc, cx2.avsc
>
>
> Hive enables table schema evolution via properties. For avro e.g. we can alter the 'avro.schema.url' property to update table schema to the next version. Updating properties however doesn't affect column list stored in metastore DB so the table is not in the newest version when returned from metastore API. This is problem for tools working with metastore (e.g. Presto).
> To solve this issue I suggest to introduce new DDL statement syncing metastore columns with those from serde:
> {code}
> ALTER TABLE user_test1 UPDATE COLUMNS
> {code}
> Note that this is format independent solution. 
> To reproduce, follow the instructions below:
> - Create table based on avro schema version 1 (cxv1.avsc)
> {code}
> CREATE EXTERNAL TABLE user_test1
>   PARTITIONED BY (dt string)
>   ROW FORMAT SERDE
>   'org.apache.hadoop.hive.serde2.avro.AvroSerDe'
>   STORED AS INPUTFORMAT
>   'org.apache.hadoop.hive.ql.io.avro.AvroContainerInputFormat'
>   OUTPUTFORMAT
>   'org.apache.hadoop.hive.ql.io.avro.AvroContainerOutputFormat'
>   LOCATION
>   '/tmp/schema-evolution/user_test1'
>   TBLPROPERTIES ('avro.schema.url'='/tmp/schema-evolution/cx1.avsc');
> {code}
> - Update schema to version 2 (cx2.avsc)
> {code}
> ALTER TABLE user_test1 SET TBLPROPERTIES ('avro.schema.url' = '/tmp/schema-evolution/cx2.avsc');
> {code}
> - Print serde columns (top info) and metastore columns (Detailed Table Information):
> {code}
> DESCRIBE EXTENDED user_test1
> {code}



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