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https://issues.apache.org/jira/browse/TAJO-1952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15291409#comment-15291409
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ASF GitHub Bot commented on TAJO-1952:
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Github user blrunner commented on the pull request:
https://github.com/apache/tajo/pull/1020#issuecomment-220376310
At first, I approached to make another fragment for partitioned table. But
now, the only difference between ``FileFragment`` and ``PartitionFileFragment``
is the partition key. So, I would prefer to add the variable to
``FileFragment`` instead of making ``PartitionFileFragment``. It will decrease
unnecessary modifications and will avoid side effects by
``PartitionFileFragment``. Here are codes by above approach.
https://github.com/apache/tajo/compare/master...blrunner:TAJO-1952-2?expand=1.
> Implement PartitionFileFragment
> -------------------------------
>
> Key: TAJO-1952
> URL: https://issues.apache.org/jira/browse/TAJO-1952
> Project: Tajo
> Issue Type: Sub-task
> Components: Planner/Optimizer, Storage
> Reporter: Jaehwa Jung
> Assignee: Jaehwa Jung
> Fix For: 0.12.0
>
> Attachments: TAJO-1952.patch, TAJO-1952_2.patch
>
>
> Currently, PartitionedTableScanNode contains the list of partitions and it
> seems to me that the list has some problems as following:
> 1. Duplicate Informs: Task contains Fragment which specify target directory
> or target file for scanning. A path of partition lists already would write to
> Fragment.
> 2. Network Resource: When scanning lost of partition, it will occupy network
> resource, for example, several hundred kilobytes or more. It looks like an
> unnecessary resource because Fragment already has the path of partitions.
> I want to improve above problems by implementing new Fragment called
> PartitionedFileFragment. Currently, I'm planning the implementation as
> following:
> * PartitionedFileFragment will borrow FileFragment and it contains the
> partition path and the partition key values.
> * Remove the path array of partitions from PartitionedTableScanNode.
> * Implement a method for getting filtered partition directories in
> FileTableSpace.
> * Implement a method for making PartitionedFileFragment array.
> * Before making splits, call above method and use it for making splits.
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