[jira] [Created] (SPARK-32635) When pyspark.sql.functions.lit() function is used with dataframe cache, it returns wrong result

["Vinod KC (Jira)" <ji...@apache.org>]

Vinod KC created SPARK-32635:
--------------------------------

             Summary: When pyspark.sql.functions.lit() function is used with dataframe cache, it returns wrong result
                 Key: SPARK-32635
                 URL: https://issues.apache.org/jira/browse/SPARK-32635
             Project: Spark
          Issue Type: Bug
          Components: PySpark, SQL
    Affects Versions: 3.0.0
            Reporter: Vinod KC


When pyspark.sql.functions.lit() function is used with dataframe cache, it returns wrong result

eg:

### lit() function with cache() function.
-----------------------------------
{code:java}
from pyspark.sql import Row
from pyspark.sql import functions as F

df_1 = spark.createDataFrame(Row(**x) for x in [{'col1': 'b'}]).withColumn("col2", F.lit(str(2)))
df_2 = spark.createDataFrame(Row(**x) for x in [{'col1': 'a', 'col3': 8}]).withColumn("col2", F.lit(str(1)))
df_3 = spark.createDataFrame(Row(**x) for x in [{'col1': 'b', 'col3': 9}]).withColumn("col2", F.lit(str(2)))
df_23 = df_2.union(df_3)
df_4 = spark.createDataFrame(Row(**x) for x in [{'col3': 9}]).withColumn("col2", F.lit(str(2)))

sel_col3 = df_23.select('col3', 'col2')
df_4 = df_4.join(sel_col3, on=['col3', 'col2'], how = "inner")
df_23_a = df_23.join(df_1, on=["col1", 'col2'], how="inner").cache() 
finaldf = df_23_a.join(df_4, on=['col2', 'col3'], how='left').filter(F.col('col3') == 9)
finaldf.show(
finaldf.select('col2').show() #Wrong result
{code}
 


Output
-----------
{code:java}
>>> finaldf.show()
+----+----+----+
|col2|col3|col1|
+----+----+----+
| 2| 9| b|
+----+----+----+
>>> finaldf.select('col2').show() #Wrong result, instead of 2, got 1
+----+
|col2|
+----+
| 1|
+----+
+----+{code}
 


### lit() function without cache() function.
{code:java}
from pyspark.sql import Row
from pyspark.sql import functions as F

df_1 = spark.createDataFrame(Row(**x) for x in [{'col1': 'b'}]).withColumn("col2", F.lit(str(2)))
df_2 = spark.createDataFrame(Row(**x) for x in [{'col1': 'a', 'col3': 8}]).withColumn("col2", F.lit(str(1)))
df_3 = spark.createDataFrame(Row(**x) for x in [{'col1': 'b', 'col3': 9}]).withColumn("col2", F.lit(str(2)))
df_23 = df_2.union(df_3)
df_4 = spark.createDataFrame(Row(**x) for x in [{'col3': 9}]).withColumn("col2", F.lit(str(2)))

sel_col3 = df_23.select('col3', 'col2')
df_4 = df_4.join(sel_col3, on=['col3', 'col2'], how = "inner")
df_23_a = df_23.join(df_1, on=["col1", 'col2'], how="inner")
finaldf = df_23_a.join(df_4, on=['col2', 'col3'], how='left').filter(F.col('col3') == 9)
finaldf.show() 
finaldf.select('col2').show() #Correct result
{code}
 

Output
{code:java}
----------
>>> finaldf.show()
+----+----+----+
|col2|col3|col1|
+----+----+----+
| 2| 9| b|
+----+----+----+
>>> finaldf.select('col2').show() #Correct result, when df_23_a is not cached 
+----+
|col2|
+----+
| 2|
+----+
{code}
 



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org