[jira] [Created] (HIVE-20358) Allow setting variable value from Hive metastore table properties

[Zheng Shao (JIRA)]

Zheng Shao created HIVE-20358:
---------------------------------

             Summary: Allow setting variable value from Hive metastore table 
properties
                 Key: HIVE-20358
                 URL: https://issues.apache.org/jira/browse/HIVE-20358
             Project: Hive
          Issue Type: New Feature
          Components: Query Processor
            Reporter: Zheng Shao


Hive already supports set command as well as variable substitution:


{{set start_ds=2018-08-01;}}

{{SELECT COUNT(*) FROM t WHERE ds >= '${hiveconf:start_ds}';}}

 

Or:

{{set start_ds='2018-08-01';}}

{{SELECT COUNT(*) FROM t WHERE ds >= ${hiveconf:start_ds};}}

 

This issue propose to extend the set syntax to allow running UDF and a UDF that 
queries metastore:

{{SET <VARIABLE_NAME> <EXPRESSION>;}}

 

For example:

{{set start_ds GET_TABLE_PROPERTY('mydb', 'mytable', 'last_modified_time');}}

{{set start_ds GET_PARTITION_PROPERTY('mydb', 'mytable', 'ds=2018-01-01/hr=12', 
'last_modified_time');}}

 

This will allow query workflows like the following:

{{set last_run_time GET_TABLE_PROPERTY('mydb', 'mytable', 
'last_modified_time');}}

{{INSERT INTO TABLE mytable SELECT * FROM src WHERE src.time > last_run_time;}}

 



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