[
https://issues.apache.org/jira/browse/TAJO-1359?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14532985#comment-14532985
]
ASF GitHub Bot commented on TAJO-1359:
--------------------------------------
Github user jihoonson commented on the pull request:
https://github.com/apache/tajo/pull/422#issuecomment-99936194
@hyunsik, thanks for your nice work. I've left some trivial comments.
In addition, I met an error while running an example in the unit test as
follows.
```
default> create external table test (title TEXT, name RECORD (
first_name TEXT, last_name TEXT ) ) USING JSON LOCATION
'hdfs://localhost:7020/test/';
OK
default> \d
test
default> \d test
table name: default.test
table path: hdfs://localhost:7020/test
store type: JSON
number of rows: unknown
volume: 257 B
Options:
'text.serde'='org.apache.tajo.storage.json.JsonLineSerDe'
schema:
title TEXT
name RECORD (first_name TEXT, last_name TEXT)
default> select * from test;
ERROR: java.lang.NullPointerException
```
Here is the log.
```
2015-05-08 01:47:37,239 INFO org.apache.tajo.master.GlobalEngine: Query:
select * from test
2015-05-08 01:47:37,323 ERROR org.apache.tajo.master.GlobalEngine:
Stack Trace:
java.lang.NullPointerException
at
org.apache.tajo.catalog.DDLBuilder.buildSchema(DDLBuilder.java:76)
at
org.apache.tajo.catalog.SchemaUtil.toDisplayString(SchemaUtil.java:161)
at org.apache.tajo.catalog.TypeDesc.toString(TypeDesc.java:66)
at org.apache.tajo.catalog.Column.toString(Column.java:159)
at java.lang.String.valueOf(String.java:2847)
at java.lang.StringBuilder.append(StringBuilder.java:128)
at org.apache.tajo.catalog.Schema.toString(Schema.java:503)
at
org.apache.tajo.plan.logical.ScanNode.getPlanString(ScanNode.java:246)
at
org.apache.tajo.plan.visitor.ExplainLogicalPlanVisitor.visitScan(ExplainLogicalPlanVisitor.java:195)
at
org.apache.tajo.plan.visitor.ExplainLogicalPlanVisitor.visitScan(ExplainLogicalPlanVisitor.java:32)
at
org.apache.tajo.plan.visitor.BasicLogicalPlanVisitor.visit(BasicLogicalPlanVisitor.java:108)
at
org.apache.tajo.plan.visitor.ExplainLogicalPlanVisitor.visitUnaryNode(ExplainLogicalPlanVisitor.java:130)
at
org.apache.tajo.plan.visitor.ExplainLogicalPlanVisitor.visitProjection(ExplainLogicalPlanVisitor.java:88)
at
org.apache.tajo.plan.visitor.ExplainLogicalPlanVisitor.visitProjection(ExplainLogicalPlanVisitor.java:32)
at
org.apache.tajo.plan.visitor.BasicLogicalPlanVisitor.visit(BasicLogicalPlanVisitor.java:69)
at
org.apache.tajo.plan.visitor.ExplainLogicalPlanVisitor.visitRoot(ExplainLogicalPlanVisitor.java:81)
at
org.apache.tajo.plan.visitor.ExplainLogicalPlanVisitor.visitRoot(ExplainLogicalPlanVisitor.java:32)
at
org.apache.tajo.plan.visitor.BasicLogicalPlanVisitor.visit(BasicLogicalPlanVisitor.java:60)
at
org.apache.tajo.plan.visitor.ExplainLogicalPlanVisitor.getBlockPlanStrings(ExplainLogicalPlanVisitor.java:74)
at
org.apache.tajo.plan.LogicalPlan.getLogicalPlanAsString(LogicalPlan.java:344)
at
org.apache.tajo.plan.LogicalPlan.getQueryGraphAsString(LogicalPlan.java:334)
at org.apache.tajo.plan.LogicalPlan.toString(LogicalPlan.java:366)
at
org.apache.tajo.master.GlobalEngine.createLogicalPlan(GlobalEngine.java:275)
at
org.apache.tajo.master.GlobalEngine.executeQuery(GlobalEngine.java:186)
at
org.apache.tajo.master.TajoMasterClientService$TajoMasterClientProtocolServiceHandler.submitQuery(TajoMasterClientService.java:287)
```
> Add nested field projector and language extension to project nested record
> --------------------------------------------------------------------------
>
> Key: TAJO-1359
> URL: https://issues.apache.org/jira/browse/TAJO-1359
> Project: Tajo
> Issue Type: Sub-task
> Components: parser, physical operator, planner/optimizer
> Reporter: Hyunsik Choi
> Assignee: Hyunsik Choi
> Fix For: 0.11.0
>
> Attachments: TAJO-1359.patch, TAJO-1359_2.patch, TAJO-1359_3.patch,
> TAJO-1359_4.patch, TAJO-1359_5.patch, TAJO-1359_6.patch, TAJO-1359_7.patch
>
>
> We need to improve Projector class to get nested record fields, and we also
> add some language extension to specify certain nested records in table
> schema. Both works should be done together. Otherwise, we need to test an
> entire work process.
> Using dot '.' would be good for the syntax to specify nested fields. Many
> systems (Hive, Google BigQuery, and Drill) already use this syntax. Probably,
> many users are familiar with this form.
> For example, if *employee* is a root nested record field and it includes
> *age* and *name* fields, consisting two fields lastname and firstname, we can
> specify them individually as follows:
> {code}
> SELECT employee.age, employee.name.lastname, employee.name.firstname FROM ...
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
