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HyukjinKwon 830249284d [SPARK-34059][SQL][CORE] Use for/foreach rather than map to make sure execute it eagerly 
### What changes were proposed in this pull request?

This PR is basically a followup of https://github.com/apache/spark/pull/14332.
Calling `map` alone might leave it not executed due to lazy evaluation, e.g.)

```
scala> val foo = Seq(1,2,3)
foo: Seq[Int] = List(1, 2, 3)

scala> foo.map(println)
1
2
3
res0: Seq[Unit] = List((), (), ())

scala> foo.view.map(println)
res1: scala.collection.SeqView[Unit,Seq[_]] = SeqViewM(...)

scala> foo.view.foreach(println)
1
2
3
```

We should better use `foreach` to make sure it's executed where the output is unused or `Unit`.

### Why are the changes needed?

To prevent the potential issues by not executing `map`.

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

No, the current codes look not causing any problem for now.

### How was this patch tested?

I found these item by running IntelliJ inspection, double checked one by one, and fixed them. These should be all instances across the codebase ideally.

Closes #31110 from HyukjinKwon/SPARK-34059.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: Liang-Chi Hsieh <viirya@gmail.com>
2021-01-10 15:22:24 -08:00
..
catalyst [SPARK-34059][SQL][CORE] Use for/foreach rather than map to make sure execute it eagerly 2021-01-10 15:22:24 -08:00
core [SPARK-34059][SQL][CORE] Use for/foreach rather than map to make sure execute it eagerly 2021-01-10 15:22:24 -08:00
hive [SPARK-34055][SQL][TESTS][FOLLOWUP] Increase the expected number of calls to Hive external catalog in partition adding 2021-01-10 18:29:02 +09:00
hive-thriftserver [SPARK-33100][SQL][FOLLOWUP] Find correct bound of bracketed comment in spark-sql 2021-01-07 20:49:37 +09:00
create-docs.sh [SPARK-34010][SQL][DODCS] Use python3 instead of python in SQL documentation build 2021-01-05 19:48:10 +09:00
gen-sql-api-docs.py [SPARK-34022][DOCS][FOLLOW-UP] Fix typo in SQL built-in function docs 2021-01-06 09:28:22 -08:00
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.