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alexander-daskalov 10edeafc69 [MINOR][SQL] Fixed approx_count_distinct rsd param description 
### What changes were proposed in this pull request?

In the docs concerning the approx_count_distinct I have changed the description of the rsd parameter from **_maximum estimation error allowed_** to _**maximum relative standard deviation allowed**_

### Why are the changes needed?

Maximum estimation error allowed can be misleading. You can set the target relative standard deviation, which affects the estimation error, but on given runs the estimation error can still be above the rsd parameter.

### Does this PR introduce _any_ user-facing change?

This PR should make it easier for users reading the docs to understand that the rsd parameter in approx_count_distinct doesn't cap the estimation error, but just sets the target deviation instead,

### How was this patch tested?

No tests, as no code changes were made.

Closes #29424 from Comonut/fix-approx_count_distinct-rsd-param-description.

Authored-by: alexander-daskalov <alexander.daskalov@adevinta.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
2020-08-14 22:10:41 +09:00
..
catalyst [MINOR][SQL] Fixed approx_count_distinct rsd param description 2020-08-14 22:10:41 +09:00
core [MINOR][SQL] Fixed approx_count_distinct rsd param description 2020-08-14 22:10:41 +09:00
hive [SPARK-20680][SQL][FOLLOW-UP] Add HiveVoidType in HiveClientImpl 2020-08-14 06:59:15 +00:00
hive-thriftserver [SPARK-32492][SQL][FOLLOWUP][TEST-MAVEN] Fix jenkins maven jobs 2020-08-05 13:56:11 +00:00
create-docs.sh [SPARK-31550][SQL][DOCS] Set nondeterministic configurations with general meanings in sql configuration doc 2020-04-27 17:08:52 +09:00
gen-sql-api-docs.py [SPARK-31474][SQL][FOLLOWUP] Replace _FUNC_ placeholder with functionname in the note field of expression info 2020-04-23 13:33:04 +09:00
gen-sql-config-docs.py [SPARK-31550][SQL][DOCS] Set nondeterministic configurations with general meanings in sql configuration doc 2020-04-27 17:08:52 +09:00
gen-sql-functions-docs.py [SPARK-31562][SQL] Update ExpressionDescription for substring, current_date, and current_timestamp 2020-04-26 11:46:52 -07:00
mkdocs.yml [SPARK-30731] Update deprecated Mkdocs option 2020-02-19 17:28:58 +09:00
README.md [SPARK-30510][SQL][DOCS] Publicly document Spark SQL configuration options 2020-02-09 19:20:47 +09:00

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 extensions that allow users to write queries using a subset of HiveQL and access data from a Hive Metastore using Hive SerDes. There are also wrappers that allow 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, and SQL configuration documentation that gets included as part of configuration.md in the main docs directory.