[GitHub] [spark] WeichenXu123 opened a new pull request #25359: [SPARK-28621][SQL] Fix CheckCartesianProducts.isCartesianProduct

[GitBox <gi...@apache.org>]

WeichenXu123 opened a new pull request #25359: [SPARK-28621][SQL] Fix CheckCartesianProducts.isCartesianProduct
URL: https://github.com/apache/spark/pull/25359
 
 
   ## What changes were proposed in this pull request?
   
   Fix `CheckCartesianProducts.isCartesianProduct` so that
   1) when left or right side table can broadcast, then do not raise `Detected implicit cartesian product...` exception.
   2) when left or right side table both cannot broadcast and join conditions do not include equi-condition, then raise `Detected implicit cartesian product...` exception.
   
   ## How was this patch tested?
   
   Manual.
   
   Providing
   ```
   spark.range(2).createOrReplaceTempView("sm1") // can be broadcast
   spark.range(50000000).createOrReplaceTempView("bg1") // cannot be broadcast
   spark.range(60000000).createOrReplaceTempView("bg2") // cannot be broadcast
   ```
   and suppose `spark.sql.crossJoin.enabled=false`
   
   ### Test1
   Run
   ```
   spark.sql("select sm1.id, bg1.id from bg1 join sm1 where sm1.id < bg1.id").explain
   ```
   **Before**:
   `Detected implicit cartesian product...` exception raised.
   **After**:
   Print correct sql plan like:
   ```
   == Physical Plan ==
   *(3) Project [id#10L, id#0L]
   +- BroadcastNestedLoopJoin BuildRight, Inner, (id#10L < id#0L)
      :- *(1) Range (0, 50000000, step=1, splits=1)
      +- BroadcastExchange IdentityBroadcastMode
         +- *(2) Range (0, 2, step=1, splits=1)
   ```
   
   ### Test2
   Run
   ```
   spark.sql("select bg2.id, bg1.id from bg1 join bg2 where bg2.id < bg1.id").explain
   ```
   **Before**
   Print planner include Cartesian join (BUT we expect a `Detected implicit cartesian product...` exception raised):
   ```
   == Physical Plan ==
   *(3) Project [id#0L, id#2L]
   +- CartesianProduct (id#0L < id#2L)
      :- *(1) Range (0, 50000000, step=1, splits=1)
      +- *(2) Range (0, 60000000, step=1, splits=1)
   ```
   **After**:
   `Detected implicit cartesian product...` exception raised.
   
   Please review https://spark.apache.org/contributing.html before opening a pull request.
   

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