[GitHub] [spark] wangyum commented on a change in pull request #34291: [SPARK-37020][SQL] DS V2 LIMIT push down

Mon, 25 Oct 2021 02:33:44 -0700 


wangyum commented on a change in pull request #34291:
URL: https://github.com/apache/spark/pull/34291#discussion_r735423861



##########
File path: 
sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/V2ScanRelationPushDown.scala
##########
@@ -225,6 +225,37 @@ object V2ScanRelationPushDown extends Rule[LogicalPlan] 
with PredicateHelper {
       withProjection
   }
 
+  def applyLimit(plan: LogicalPlan): LogicalPlan = plan.transform {
+    case globalLimit @ GlobalLimit(_, l @ 
LocalLimit(IntegerLiteral(limitValue), child)) =>

Review comment:
       This is MySQL benchmark result:
   ```shell
   bin/spark-shell --queue default --conf 
spark.sql.catalog.mysql=org.apache.spark.sql.execution.datasources.v2.jdbc.JDBCTableCatalog
 --conf spark.sql.catalog.mysql.driver=com.mysql.jdbc.Driver --conf 
"spark.sql.catalog.mysql.url=jdbc:mysql://ipToMySQL:3306/mydb?user=userName&password=mypasswd"
 --conf spark.sql.catalog.mysql.pushDownLimit=true
   ```
   
   
   without pushdown | with pushdown
   --- | ---
   
![image](https://user-images.githubusercontent.com/5399861/138671426-a58a7f0d-1846-4b34-88d7-2cb5ce9a29a8.png)
 | 
![image](https://user-images.githubusercontent.com/5399861/138671580-dc02a200-3417-48dc-86ba-978bbe8c4b06.png)
   
   
   




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]



---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to