ODIn/spark-instrumented-optimizer
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity
spark-instrumented-optimizer/sql
History
Takeshi Yamamuro 6103cf1960 [SPARK-30200][SQL] Add ExplainMode for Dataset.explain 
### What changes were proposed in this pull request?

This pr intends to add `ExplainMode` for explaining `Dataset/DataFrame` with a given format mode (`ExplainMode`). `ExplainMode` has four types along with the SQL EXPLAIN command: `Simple`, `Extended`, `Codegen`, `Cost`, and `Formatted`.

For example, this pr enables users to explain DataFrame/Dataset with the `FORMATTED` format implemented in #24759;
```
scala> spark.range(10).groupBy("id").count().explain(ExplainMode.Formatted)
== Physical Plan ==
* HashAggregate (3)
+- * HashAggregate (2)
   +- * Range (1)

(1) Range [codegen id : 1]
Output: [id#0L]

(2) HashAggregate [codegen id : 1]
Input: [id#0L]

(3) HashAggregate [codegen id : 1]
Input: [id#0L, count#8L]
```

This comes from [the cloud-fan suggestion.](https://github.com/apache/spark/pull/24759#issuecomment-560211270)

### Why are the changes needed?

To follow the SQL EXPLAIN command.

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

No, this is just for a new API in Dataset.

### How was this patch tested?

Add tests in `ExplainSuite`.

Closes #26829 from maropu/DatasetExplain.

Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2019-12-10 09:51:29 -08:00
..
catalyst [SPARK-30125][SQL] Remove PostgreSQL dialect 2019-12-11 01:22:34 +08:00
core [SPARK-30200][SQL] Add ExplainMode for Dataset.explain 2019-12-10 09:51:29 -08:00
hive [SPARK-30159][SQL][FOLLOWUP] Fix lint-java via removing unnecessary imports 2019-12-09 08:57:20 -08:00
hive-thriftserver [SPARK-30125][SQL] Remove PostgreSQL dialect 2019-12-11 01:22:34 +08:00
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-27328][SQL] Add 'deprecated' in ExpressionDescription for extended usage and SQL doc 2019-04-09 13:49:42 +08:00
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-28980][CORE][SQL][STREAMING][MLLIB] Remove most items deprecated in Spark 2.2.0 or earlier, for Spark 3 2019-09-09 10:19:40 -05:00

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.