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Gengliang Wang 9fdc2a0801 [SPARK-31793][SQL] Reduce the memory usage in file scan location metadata 
### What changes were proposed in this pull request?

Currently, the data source scan node stores all the paths in its metadata. The metadata is kept when a SparkPlan is converted into SparkPlanInfo. SparkPlanInfo can be used to construct the Spark plan graph in UI.

However, the paths can be very large (e.g. it can be many partitions after partition pruning), while UI pages only require up to 100 bytes for the location metadata. We can reduce the paths stored in metadata to reduce memory usage.

### Why are the changes needed?

Reduce unnecessary memory cost.
In the heap dump of a driver, the SparkPlanInfo instances are quite large and it should be avoided:
![image](https://user-images.githubusercontent.com/1097932/82642318-8f65de00-9bc2-11ea-9c9c-f05c2b0e1c49.png)

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

No

### How was this patch tested?

Unit tests

Closes #28610 from gengliangwang/improveLocationMetadata.

Authored-by: Gengliang Wang <gengliang.wang@databricks.com>
Signed-off-by: Gengliang Wang <gengliang.wang@databricks.com>
2020-05-23 15:00:28 -07:00
..
catalyst [SPARK-31710][SQL] Adds TIMESTAMP_SECONDS, TIMESTAMP_MILLIS and TIMESTAMP_MICROS functions 2020-05-22 14:16:30 +00:00
core [SPARK-31793][SQL] Reduce the memory usage in file scan location metadata 2020-05-23 15:00:28 -07:00
hive [SPARK-31684][SQL] Overwrite partition failed with 'WRONG FS' when the target partition is not belong to the filesystem as same as the table 2020-05-19 14:08:51 +00:00
hive-thriftserver Revert "[SPARK-31765][WEBUI] Upgrade HtmlUnit >= 2.37.0" 2020-05-21 16:00:58 -07:00
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.