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CodingCat ab7346f20c [SPARK-22673][SQL] InMemoryRelation should utilize existing stats whenever possible 
## What changes were proposed in this pull request?

The current implementation of InMemoryRelation always uses the most expensive execution plan when writing cache
With CBO enabled, we can actually have a more exact estimation of the underlying table size...

## How was this patch tested?

existing test

Author: CodingCat <zhunansjtu@gmail.com>
Author: Nan Zhu <CodingCat@users.noreply.github.com>
Author: Nan Zhu <nanzhu@uber.com>

Closes #19864 from CodingCat/SPARK-22673.
2017-12-19 21:51:56 +08:00
..
catalyst [MINOR][SQL] Remove Useless zipWithIndex from ResolveAliases 2017-12-19 09:48:31 +08:00
core [SPARK-22673][SQL] InMemoryRelation should utilize existing stats whenever possible 2017-12-19 21:51:56 +08:00
hive [SPARK-22745][SQL] read partition stats from Hive 2017-12-13 16:27:29 +08:00
hive-thriftserver Revert "Revert "[SPARK-22496][SQL] thrift server adds operation logs"" 2017-12-19 07:30:29 +09:00
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.