[
https://issues.apache.org/jira/browse/SPARK-19655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15873184#comment-15873184
]
Hyukjin Kwon commented on SPARK-19655:
--------------------------------------
I guess the problematic line is,
https://github.com/apache/spark/blob/5857b9ac2d9808d9b89a5b29620b5052e2beebf5/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JDBCRDD.scala#L209-L213
This is a subset of SPARK-12449 because I guess we are currently pushing down
columns and filters via
https://github.com/apache/spark/blob/6a9a85b84decc2cbe1a0d8791118a0f91a62aa3f/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceStrategy.scala#L440-L512
I don;t think we are going to separately solve this problem only for
{{count(*)}}. Could we resolve this as a duplicate?
> select count(*) , requests 1 for each row
> -----------------------------------------
>
> Key: SPARK-19655
> URL: https://issues.apache.org/jira/browse/SPARK-19655
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.1.0
> Reporter: hosein
> Priority: Minor
>
> when I want query select count( * ) by JDBC and monitor queries in database
> side, I see spark requests: select 1 for destination table
> it means 1 for each row and it is not optimized
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
