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https://issues.apache.org/jira/browse/TAJO-1832?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14804744#comment-14804744
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ASF GitHub Bot commented on TAJO-1832:
--------------------------------------
Github user hyunsik commented on a diff in the pull request:
https://github.com/apache/tajo/pull/756#discussion_r39815028
--- Diff:
tajo-catalog/tajo-catalog-common/src/main/java/org/apache/tajo/catalog/TableDesc.java
---
@@ -35,34 +36,43 @@
public class TableDesc implements ProtoObject<TableDescProto>, GsonObject,
Cloneable {
@Expose protected String tableName; // required
- @Expose protected Schema schema;
+ @Expose protected Schema schema; // optional
for self-describing tables
@Expose protected TableMeta meta; // required
/** uri is set if external flag is TRUE. */
- @Expose protected URI uri; // optional
+ @Expose protected URI uri; // optional
--- End diff --
In the last work, I changed URI to be required. Regardless of whether it is
manged or external, every TableDescs has the table URI. The evidence is unused
``TableDesc::hasUri()``, which can be removed. Additional evidence is that
there is no nullity check around ``getUri()``.
Otherwise, it is a bug.
> Well support for self-describing data formats
> ---------------------------------------------
>
> Key: TAJO-1832
> URL: https://issues.apache.org/jira/browse/TAJO-1832
> Project: Tajo
> Issue Type: New Feature
> Components: Planner/Optimizer
> Reporter: Jihoon Son
> Assignee: Jihoon Son
>
> *Problem*
> Tajo already has a support for self-describing data formats like JSON,
> Parquet, or ORC. While they are capable of providing schema information by
> themselves, users must define schema to query on them with the current
> implementation. To solve this inconvenience, we have to improve our query
> planner to support self-describing data formats well.
> *Solution*
> First, we need to allow omitting schema definition for the create table
> statement. When a query is submitted for a self-describing table, the columns
> which don't exist in that table will be filled with Nulls.
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