Details

Type: Bug
Status: Resolved
Priority: Major
Resolution: Fixed
Affects Version/s: 3.1.2
Fix Version/s: 3.2.0, 3.1.3
Component/s: SQL
Labels:
- correctness

Description

When joining two dataframes, if they share the same lineage and one dataframe is a transformation of the other, Ambiguous Self Join detection only works when transformed dataframe is the right dataframe.

For instance df1 and df2 where df2 is a filtered df1, Ambiguous Self Join detection only works when df2 is the right dataframe:

df1.join(df2, ...) correctly fails with Ambiguous Self Join error
df2.join(df1, ...) returns a valid dataframe

Minimum Reproducible example

Code

import sparkSession.implicit._

val df1 = Seq((1, 2, "A1"),(2, 1, "A2")).toDF("key1", "key2", "value")

val df2 = df1.filter($"value" === "A2")

df2.join(df1, df1("key1") === df2("key2")).show()

Expected Result

Throw the following exception:

Exception in thread "main" org.apache.spark.sql.AnalysisException: Column key2#11 are ambiguous. It's probably because you joined several Datasets together, and some of these Datasets are the same. This column points to one of the Datasets but Spark is unable to figure out which one. Please alias the Datasets with different names via `Dataset.as` before joining them, and specify the column using qualified name, e.g. `df.as("a").join(df.as("b"), $"a.id" > $"b.id")`. You can also set spark.sql.analyzer.failAmbiguousSelfJoin to false to disable this check.
	at org.apache.spark.sql.execution.analysis.DetectAmbiguousSelfJoin$.apply(DetectAmbiguousSelfJoin.scala:157)
	at org.apache.spark.sql.execution.analysis.DetectAmbiguousSelfJoin$.apply(DetectAmbiguousSelfJoin.scala:43)
	at org.apache.spark.sql.catalyst.rules.RuleExecutor.$anonfun$execute$2(RuleExecutor.scala:216)
	at scala.collection.LinearSeqOptimized.foldLeft(LinearSeqOptimized.scala:126)
	at scala.collection.LinearSeqOptimized.foldLeft$(LinearSeqOptimized.scala:122)
	at scala.collection.immutable.List.foldLeft(List.scala:91)
	at org.apache.spark.sql.catalyst.rules.RuleExecutor.$anonfun$execute$1(RuleExecutor.scala:213)
	at org.apache.spark.sql.catalyst.rules.RuleExecutor.$anonfun$execute$1$adapted(RuleExecutor.scala:205)
	at scala.collection.immutable.List.foreach(List.scala:431)
	at org.apache.spark.sql.catalyst.rules.RuleExecutor.execute(RuleExecutor.scala:205)
	at org.apache.spark.sql.catalyst.analysis.Analyzer.org$apache$spark$sql$catalyst$analysis$Analyzer$$executeSameContext(Analyzer.scala:196)
	at org.apache.spark.sql.catalyst.analysis.Analyzer.execute(Analyzer.scala:190)
	at org.apache.spark.sql.catalyst.analysis.Analyzer.execute(Analyzer.scala:155)
	at org.apache.spark.sql.catalyst.rules.RuleExecutor.$anonfun$executeAndTrack$1(RuleExecutor.scala:183)
	at org.apache.spark.sql.catalyst.QueryPlanningTracker$.withTracker(QueryPlanningTracker.scala:88)
	at org.apache.spark.sql.catalyst.rules.RuleExecutor.executeAndTrack(RuleExecutor.scala:183)
	at org.apache.spark.sql.catalyst.analysis.Analyzer.$anonfun$executeAndCheck$1(Analyzer.scala:174)
	at org.apache.spark.sql.catalyst.plans.logical.AnalysisHelper$.markInAnalyzer(AnalysisHelper.scala:228)
	at org.apache.spark.sql.catalyst.analysis.Analyzer.executeAndCheck(Analyzer.scala:173)
	at org.apache.spark.sql.execution.QueryExecution.$anonfun$analyzed$1(QueryExecution.scala:73)
	at org.apache.spark.sql.catalyst.QueryPlanningTracker.measurePhase(QueryPlanningTracker.scala:111)
	at org.apache.spark.sql.execution.QueryExecution.$anonfun$executePhase$1(QueryExecution.scala:143)
	at org.apache.spark.sql.SparkSession.withActive(SparkSession.scala:775)
	at org.apache.spark.sql.execution.QueryExecution.executePhase(QueryExecution.scala:143)
	at org.apache.spark.sql.execution.QueryExecution.analyzed$lzycompute(QueryExecution.scala:73)
	at org.apache.spark.sql.execution.QueryExecution.analyzed(QueryExecution.scala:71)
	at org.apache.spark.sql.execution.QueryExecution.assertAnalyzed(QueryExecution.scala:63)
	at org.apache.spark.sql.Dataset$.$anonfun$ofRows$1(Dataset.scala:90)
	at org.apache.spark.sql.SparkSession.withActive(SparkSession.scala:775)
	at org.apache.spark.sql.Dataset$.ofRows(Dataset.scala:88)
	at org.apache.spark.sql.Dataset.withPlan(Dataset.scala:3715)
	at org.apache.spark.sql.Dataset.join(Dataset.scala:1079)
	at org.apache.spark.sql.Dataset.join(Dataset.scala:1041)
 ...

Actual result

Empty dataframe:

+----+----+-----+----+----+-----+
|key1|key2|value|key1|key2|value|
+----+----+-----+----+----+-----+
+----+----+-----+----+----+-----+

Attachments

Issue Links

Parent Feature

SPARK-28344 fail the query if detect ambiguous self join

Resolved

links to

[Github] Pull Request #34172 (sarutak)

[Github] Pull Request #34205 (sarutak)

Ambiguous Self-Join detected only on right dataframe