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Liang-Chi Hsieh 9e1b204bcc [SPARK-35410][SQL] SubExpr elimination should not include redundant children exprs in conditional expression 
### What changes were proposed in this pull request?

This patch fixes a bug when dealing with common expressions in conditional expressions such as `CaseWhen` during subexpression elimination.

For example, previously we find common expressions among conditions of `CaseWhen`, but children expressions are also counted into. We should not count these children expressions as common expressions.

### Why are the changes needed?

If the redundant children expressions are counted as common expressions too, they will be redundantly evaluated and miss the subexpression elimination opportunity.

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

No

### How was this patch tested?

Added tests.

Closes #32559 from viirya/SPARK-35410.

Authored-by: Liang-Chi Hsieh <viirya@gmail.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2021-05-23 08:24:44 -07:00
..
catalyst [SPARK-35410][SQL] SubExpr elimination should not include redundant children exprs in conditional expression 2021-05-23 08:24:44 -07:00
core [SPARK-35410][SQL] SubExpr elimination should not include redundant children exprs in conditional expression 2021-05-23 08:24:44 -07:00
hive [SPARK-28551][SQL][FOLLOWUP] Use the corrected hadoop conf 2021-05-22 10:33:57 +08:00
hive-thriftserver [SPARK-35286][SQL] Replace SessionState.start with SessionState.setCurrentSessionState 2021-05-16 18:39:15 +08:00
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-34747][SQL][DOCS] Add virtual operators to the built-in function document 2021-03-19 10:19:26 +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.