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Dilip Biswal 0c2ba427bc [SPARK-23095][SQL] Decorrelation of scalar subquery fails with java.util.NoSuchElementException 
## What changes were proposed in this pull request?
The following SQL involving scalar correlated query returns a map exception.
``` SQL
SELECT t1a
FROM   t1
WHERE  t1a = (SELECT   count(*)
              FROM     t2
              WHERE    t2c = t1c
              HAVING   count(*) >= 1)
```
``` SQL
key not found: ExprId(278,786682bb-41f9-4bd5-a397-928272cc8e4e)
java.util.NoSuchElementException: key not found: ExprId(278,786682bb-41f9-4bd5-a397-928272cc8e4e)
        at scala.collection.MapLike$class.default(MapLike.scala:228)
        at scala.collection.AbstractMap.default(Map.scala:59)
        at scala.collection.MapLike$class.apply(MapLike.scala:141)
        at scala.collection.AbstractMap.apply(Map.scala:59)
        at org.apache.spark.sql.catalyst.optimizer.RewriteCorrelatedScalarSubquery$.org$apache$spark$sql$catalyst$optimizer$RewriteCorrelatedScalarSubquery$$evalSubqueryOnZeroTups(subquery.scala:378)
        at org.apache.spark.sql.catalyst.optimizer.RewriteCorrelatedScalarSubquery$$anonfun$org$apache$spark$sql$catalyst$optimizer$RewriteCorrelatedScalarSubquery$$constructLeftJoins$1.apply(subquery.scala:430)
        at org.apache.spark.sql.catalyst.optimizer.RewriteCorrelatedScalarSubquery$$anonfun$org$apache$spark$sql$catalyst$optimizer$RewriteCorrelatedScalarSubquery$$constructLeftJoins$1.apply(subquery.scala:426)
```

In this case, after evaluating the HAVING clause "count(*) > 1" statically
against the binding of aggregtation result on empty input, we determine
that this query will not have a the count bug. We should simply return
the evalSubqueryOnZeroTups with empty value.
(Please fill in changes proposed in this fix)

## How was this patch tested?
A new test was added in the Subquery bucket.

Author: Dilip Biswal <dbiswal@us.ibm.com>

Closes #20283 from dilipbiswal/scalar-count-defect.
2018-01-17 09:57:30 +08:00
..
catalyst [SPARK-23095][SQL] Decorrelation of scalar subquery fails with java.util.NoSuchElementException 2018-01-17 09:57:30 +08:00
core [SPARK-23095][SQL] Decorrelation of scalar subquery fails with java.util.NoSuchElementException 2018-01-17 09:57:30 +08:00
hive [SPARK-16139][TEST] Add logging functionality for leaked threads in tests 2018-01-16 11:41:08 -08:00
hive-thriftserver [SPARK-23028] Bump master branch version to 2.4.0-SNAPSHOT 2018-01-13 00:37:59 +08:00
create-docs.sh [MINOR][DOCS] Minor doc fixes related with doc build and uses script dir in SQL doc gen script 2017-08-26 13:56:24 +09:00
gen-sql-markdown.py [SPARK-21485][FOLLOWUP][SQL][DOCS] Describes examples and arguments separately, and note/since in SQL built-in function documentation 2017-08-05 10:10:56 -07:00
mkdocs.yml [SPARK-21485][SQL][DOCS] Spark SQL documentation generation for built-in functions 2017-07-26 09:38:51 -07:00
README.md [SPARK-21485][SQL][DOCS] Spark SQL documentation generation for built-in functions 2017-07-26 09:38:51 -07:00

README.md

Spark SQL

This module provides support for executing relational queries expressed in either SQL or the DataFrame/Dataset API.

Spark SQL is broken up into four subprojects:

  • Catalyst (sql/catalyst) - An implementation-agnostic framework for manipulating trees of relational operators and expressions.
  • Execution (sql/core) - A query planner / execution engine for translating Catalyst's logical query plans into Spark RDDs. This component also includes a new public interface, SQLContext, that allows users to execute SQL or LINQ statements against existing RDDs and Parquet files.
  • Hive Support (sql/hive) - Includes an extension of SQLContext called HiveContext that allows users to write queries using a subset of HiveQL and access data from a Hive Metastore using Hive SerDes. There are also wrappers that allows users to run queries that include Hive UDFs, UDAFs, and UDTFs.
  • HiveServer and CLI support (sql/hive-thriftserver) - Includes support for the SQL CLI (bin/spark-sql) and a HiveServer2 (for JDBC/ODBC) compatible server.

Running sql/create-docs.sh generates SQL documentation for built-in functions under sql/site.