Hi All,
https://github.com/apache/spark/blob/branch-1.5/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JdbcUtils.scala#L48
In Present spark version in line 48 there is a bug, to check whether table
exists in a database using limit doesnt work for all databases sql server
for example.
best way to check whehter table exists in any database is to use, select *
from table where 1=2; or select 1 from table where 1=2; this supports all
the databases.
In spark 1.6 can this change be implemented, this lets
write.mode("append") bug to go away.
def tableExists(conn: Connection, table: String): Boolean = {
// Somewhat hacky, but there isn't a good way to identify whether a
table exists for all
// SQL database systems, considering "table" could also include the
database name.
Try(conn.prepareStatement(s"SELECT 1 FROM $table LIMIT
1").executeQuery().next()).isSuccess
}
Solution:-
def tableExists(conn: Connection, table: String): Boolean = {
// Somewhat hacky, but there isn't a good way to identify whether a
table exists for all
// SQL database systems, considering "table" could also include the
database name.
Try(conn.prepareStatement(s"SELECT 1 FROM $table where
1=2").executeQuery().next()).isSuccess
}
Thanks
On Wed, Dec 9, 2015 at 4:24 PM, Seongduk Cheon <[email protected]> wrote:
> Not for sure, but I think it is bug as of 1.5.
>
> Spark is using LIMIT keyword whether a table exists.
>
> https://github.com/apache/spark/blob/branch-1.5/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JdbcUtils.scala#L48
>
> If your database does not support LIMIT keyword such as SQL Server, spark
> try to create table
>
> https://github.com/apache/spark/blob/branch-1.5/sql/core/src/main/scala/org/apache/spark/sql/DataFrameWriter.scala#L272-L275
>
> This issue has already fixed and It will be released on 1.6
> https://issues.apache.org/jira/browse/SPARK-9078
>
>
> --
> Cheon
>
> 2015-12-09 22:54 GMT+09:00 [email protected] <[email protected]>
> :
>
>> Hi Spark Contributors,
>>
>> I am trying to append data to target table using df.write.mode("append")
>> functionality but spark throwing up table already exists exception.
>>
>> Is there a fix scheduled in later spark release ?, I am using spark 1.5.
>>
>> val sourcedfmode=sourcedf.write.mode("append")
>> sourcedfmode.jdbc(TargetDBinfo.url,TargetDBinfo.table,targetprops)
>>
>> Full Code:-
>>
>> https://github.com/kali786516/ScalaDB/blob/master/src/main/java/com/kali/db/SaprkSourceToTargetBulkLoad.scala
>>
>> Spring Config File:-
>>
>> https://github.com/kali786516/ScalaDB/blob/master/src/main/resources/SourceToTargetBulkLoad.xml
>>
>>
>> Thanks
>> Sri
>>
>>
>>
>> --
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>>
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>
>
--
Thanks & Regards
Sri Tummala
