ce6a71e013
## What changes were proposed in this pull request? Spark with Scala 2.10 fails with a group by cube: ``` spark.range(1).select($"id" as "a", $"id" as "b").write.partitionBy("a").mode("overwrite").saveAsTable("rollup_bug") spark.sql("select 1 from rollup_bug group by rollup ()").show ``` It can be traced back to https://github.com/apache/spark/pull/15484 , which made `Expand.projections` a lazy `Stream` for group by cube. In scala 2.10 `Stream` captures a lot of stuff, and in this case it captures the entire query plan which has some un-serializable parts. This change is also good for master branch, to reduce the serialized size of `Expand.projections`. ## How was this patch tested? manually verified with Spark with Scala 2.10. Author: Wenchen Fan <wenchen@databricks.com> Closes #19289 from cloud-fan/bug. |
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catalyst | ||
core | ||
hive | ||
hive-thriftserver | ||
create-docs.sh | ||
gen-sql-markdown.py | ||
mkdocs.yml | ||
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
.