GitHub user HyukjinKwon opened a pull request:
https://github.com/apache/spark/pull/14451
Make jdbc() and read.format("jdbc") consistently throwing exception for
user-specified schema
## What changes were proposed in this pull request?
Currently,
```scala
spark.read.schema(StructType(Seq())).jdbc(...),show()
```
does not throws an exception whereas
```scala
spark.read.schema(StructType(Seq())).option(...).format("jdbc").load().show()
```
does as below:
```
jdbc does not allow user-specified schemas.;
org.apache.spark.sql.AnalysisException: jdbc does not allow user-specified
schemas.;
at
org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:320)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:149)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:122)
at
org.apache.spark.sql.jdbc.JDBCSuite$$anonfun$17.apply$mcV$sp(JDBCSuite.scala:351)
```
It'd make sense throwing the exception when user specifies schema
identically.
This PR makes the behaviour consistent for both jdbc APIs.
## How was this patch tested?
Unit test in `JDBCSuite`.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/HyukjinKwon/spark SPARK-16848
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/14451.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 #14451
----
commit 3def251fb9bd213e0d343cd404f9896a576c0d74
Author: hyukjinkwon <gurwls...@gmail.com>
Date: 2016-08-02T05:07:57Z
Make jdbc() and read.format("jdbc") consistently throwing exception for
user-specified schema
----
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