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Posted to issues@spark.apache.org by "Apache Spark (JIRA)" <ji...@apache.org> on 2015/05/14 20:17:59 UTC
[jira] [Assigned] (SPARK-6444) SQL functions (either built-in or
UDF) should check for data types of their arguments
[ https://issues.apache.org/jira/browse/SPARK-6444?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Apache Spark reassigned SPARK-6444:
-----------------------------------
Assignee: Apache Spark
> SQL functions (either built-in or UDF) should check for data types of their arguments
> -------------------------------------------------------------------------------------
>
> Key: SPARK-6444
> URL: https://issues.apache.org/jira/browse/SPARK-6444
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 1.0.2, 1.1.1, 1.2.1, 1.3.0
> Reporter: Cheng Lian
> Assignee: Apache Spark
>
> SQL functions should remain unresolved if their arguments don't satisfy their argument type requirements. Take {{Sum}} as an example, the data type of {{Sum(Literal("1"))}} is {{StringType}}, and now it's considered resolved, which may cause problems.
> Here is a simplified version of a problematic query reported by [~cenyuhai]. Spark shell session for reproducing this issue:
> {code}
> import sqlContext._
> sql("""
> CREATE TABLE IF NOT EXISTS ut (
> c1 STRING,
> c2 STRING
> )
> """)
> sql("""
> SELECT SUM(c3) FROM (
> SELECT SUM(c1) AS c3, 0 AS c4 FROM ut -- (1)
> UNION ALL
> SELECT 0 AS c3, COUNT(c2) AS c4 FROM ut -- (2)
> ) t
> """).queryExecution.optimizedPlan
> {code}
> Exception thrown:
> {noformat}
> java.util.NoSuchElementException: key not found: c3#10
> at scala.collection.MapLike$class.default(MapLike.scala:228)
> at org.apache.spark.sql.catalyst.expressions.AttributeMap.default(AttributeMap.scala:29)
> at scala.collection.MapLike$class.apply(MapLike.scala:141)
> at org.apache.spark.sql.catalyst.expressions.AttributeMap.apply(AttributeMap.scala:29)
> at org.apache.spark.sql.catalyst.optimizer.UnionPushdown$$anonfun$1.applyOrElse(Optimizer.scala:80)
> at org.apache.spark.sql.catalyst.optimizer.UnionPushdown$$anonfun$1.applyOrElse(Optimizer.scala:79)
> at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$3.apply(TreeNode.scala:187)
> at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$3.apply(TreeNode.scala:187)
> at org.apache.spark.sql.catalyst.trees.CurrentOrigin$.withOrigin(TreeNode.scala:50)
> at org.apache.spark.sql.catalyst.trees.TreeNode.transformDown(TreeNode.scala:186)
> at org.apache.spark.sql.catalyst.trees.TreeNode.transform(TreeNode.scala:177)
> at org.apache.spark.sql.catalyst.optimizer.UnionPushdown$.pushToRight(Optimizer.scala:79)
> at org.apache.spark.sql.catalyst.optimizer.UnionPushdown$$anonfun$apply$1$$anonfun$applyOrElse$6.apply(Optimizer.scala:101)
> at org.apache.spark.sql.catalyst.optimizer.UnionPushdown$$anonfun$apply$1$$anonfun$applyOrElse$6.apply(Optimizer.scala:101)
> ...
> {noformat}
> The analyzed plan of the query is:
> {noformat}
> == Analyzed Logical Plan ==
> !Aggregate [], [SUM(CAST(c3#153, DoubleType)) AS _c0#157] (c)
> Union
> Project [CAST(c3#153, StringType) AS c3#164,c4#163L] (d)
> Project [c3#153,CAST(c4#154, LongType) AS c4#163L]
> Aggregate [], [SUM(CAST(c1#158, DoubleType)) AS c3#153,0 AS c4#154] (b)
> MetastoreRelation default, ut, None
> Project [CAST(c3#155, StringType) AS c3#162,c4#156L] (a)
> Aggregate [], [0 AS c3#155,COUNT(c2#161) AS c4#156L]
> MetastoreRelation default, ut, None
> {noformat}
> This case is very interesting. It involves 2 analysis rules, {{WidenTypes}} and {{PromoteStrings}}, and 1 optimizer rule, {{UnionPushdown}}. To see the details, we can turn on TRACE level log and check detailed rule execution process. The TL;DR is:
> # Since {{c1}} is STRING, {{SUM(c1)}} is also STRING (which is the root cause of the whole issue).
> # {{c3}} in {{(1)}} is STRING, while the one in {{(2)}} is INT. Thus {{WidenTypes}} casts the latter to STRING to ensure both sides of the UNION have the same schema. See {{(a)}}.
> # {{PromoteStrings}} casts {{c1}} in {{SUM(c1)}} to DOUBLE, which consequently changes data type of {{SUM(c1)}} and {{c3}} to DOUBLE. See {{(b)}}.
> # {{c3}} in the top level {{Aggregate}} is resolved as DOUBLE (c)
> # Since schemas of the two sides of the UNION are different again, {{WidenTypes}} casts {{SUM(c1) AS c3}} to STRING. See {{(d)}}.
> # Int the top level {{Aggregate}}, {{c3#153}} becomes a missing input attribute because it is hidden by {{(d)}} now.
> # In the optimizing phase, {{UnionPushdown}} throws because the top level {{Aggregate}} has missing input attribute.
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