[jira] [Commented] (TAJO-1493) Add a method to get partition directories with filter conditions.

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TAJO-1493?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14614480#comment-14614480 ] 

ASF GitHub Bot commented on TAJO-1493:
--------------------------------------

GitHub user blrunner opened a pull request:

    https://github.com/apache/tajo/pull/624

    TAJO-1493: Add a method to get partition directories with filter conditions.

    Not yet implemented unit test cases. 


You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/blrunner/tajo TAJO-1493

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/tajo/pull/624.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #624
    
----
commit 743122bade809e5a6fd6ccbb5025a87233e0ac40
Author: JaeHwa Jung <bl...@apache.org>
Date:   2015-07-06T01:49:20Z

    TAJO-1493: Add a method to get partition directories with filter conditions.

----


> Add a method to get partition directories with filter conditions.
> -----------------------------------------------------------------
>
>                 Key: TAJO-1493
>                 URL: https://issues.apache.org/jira/browse/TAJO-1493
>             Project: Tajo
>          Issue Type: Sub-task
>          Components: Catalog
>            Reporter: Jaehwa Jung
>            Assignee: Jaehwa Jung
>
> Currently, PartitionedTableRewriter take a look into partition directories for rewriting filter conditions. It get all sub directories of table path because catalog doesn’t provide partition directories. But if there are lots of sub directories on HDFS, such as, more than 10,000 directories, it might be cause overload to NameNode. Thus, CatalogStore need to provide partition directories for specified filter conditions. I designed new method to CatalogStore as follows:
> * method name: getPartitionsWithConditionFilters
> * first parameter: database name
> * second parameter: table name
> * third parameter: where clause (included target column name and partition value)
> * return values: List<org.apache.tajo.catalog.proto.CatalogProtos.TablePartitionProto>
> * description: It scan right partition directories on CatalogStore with where caluse. 
>   For examples, users set parameters as following:
> ** first parameter: default
> ** second parameter: table1
> ** third parameter: COLUMN_NAME = 'col1' AND PARTITION_VALUE = '3
> In the previous cases, this method will create select clause as follows.
> {code:xml}
> SELECT DISTINCT A.PATH
> FROM PARTITIONS A, (
>   SELECT B.PARTITION_ID
>   FROM PARTITION_KEYS B
>   WHERE B.PARTITION_ID > 0 
>   AND (
>     COLUMN_NAME = 'col1' AND PARTITION_VALUE = '3'
>   )
> ) B
> WHERE A.PARTITION_ID > 0
> AND A.TID = ${table_id}
> AND A.PARTITION_ID = B.PARTITION_ID
> {code}
> At the first time, I considered to use EvalNode instead of where clause. But I can’t use it because of recursive related problems between tajo-catalog module and tajo-plan module. So, I’ll implement utility class to convert EvalNode to SQL.



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