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Yuming Wang 91148f428b [SPARK-28481][SQL] More expressions should extend NullIntolerant 
### What changes were proposed in this pull request?

1. Make more expressions extend `NullIntolerant`.
2. Add a checker(in `ExpressionInfoSuite`) to identify whether the expression is `NullIntolerant`.

### Why are the changes needed?

Avoid skew join if the join column has many null values and can improve query performance. For examples:
```sql
CREATE TABLE t1(c1 string, c2 string) USING parquet;
CREATE TABLE t2(c1 string, c2 string) USING parquet;
EXPLAIN SELECT t1.* FROM t1 JOIN t2 ON upper(t1.c1) = upper(t2.c1);
```

Before and after this PR:
```sql
== Physical Plan ==
*(2) Project [c1#5, c2#6]
+- *(2) BroadcastHashJoin [upper(c1#5)], [upper(c1#7)], Inner, BuildLeft
   :- BroadcastExchange HashedRelationBroadcastMode(List(upper(input[0, string, true]))), [id=#41]
   :  +- *(1) ColumnarToRow
   :     +- FileScan parquet default.t1[c1#5,c2#6]
   +- *(2) ColumnarToRow
      +- FileScan parquet default.t2[c1#7]

== Physical Plan ==
*(2) Project [c1#5, c2#6]
+- *(2) BroadcastHashJoin [upper(c1#5)], [upper(c1#7)], Inner, BuildRight
   :- *(2) Project [c1#5, c2#6]
   :  +- *(2) Filter isnotnull(c1#5)
   :     +- *(2) ColumnarToRow
   :        +- FileScan parquet default.t1[c1#5,c2#6]
   +- BroadcastExchange HashedRelationBroadcastMode(List(upper(input[0, string, true]))), [id=#59]
      +- *(1) Project [c1#7]
         +- *(1) Filter isnotnull(c1#7)
            +- *(1) ColumnarToRow
               +- FileScan parquet default.t2[c1#7]

```

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

No.

### How was this patch tested?

Unit test.

Closes #28626 from wangyum/SPARK-28481.

Authored-by: Yuming Wang <yumwang@ebay.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
2020-05-29 07:28:57 +00:00
..
catalyst [SPARK-28481][SQL] More expressions should extend NullIntolerant 2020-05-29 07:28:57 +00:00
core [SPARK-28481][SQL] More expressions should extend NullIntolerant 2020-05-29 07:28:57 +00:00
hive [SPARK-31862][SQL] Remove exception wrapping in AQE 2020-05-29 04:23:38 +00:00
hive-thriftserver [SPARK-31833][SQL][TEST-HIVE1.2] Set HiveThriftServer2 with actual port while configured 0 2020-05-29 04:13:23 +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.