ODIn/spark-instrumented-optimizer
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity
spark-instrumented-optimizer/sql
History
Bruce Robbins 558f31b31c [SPARK-23963][SQL] Properly handle large number of columns in query on text-based Hive table 
## What changes were proposed in this pull request?

TableReader would get disproportionately slower as the number of columns in the query increased.

I fixed the way TableReader was looking up metadata for each column in the row. Previously, it had been looking up this data in linked lists, accessing each linked list by an index (column number). Now it looks up this data in arrays, where indexing by column number works better.

## How was this patch tested?

Manual testing
All sbt unit tests
python sql tests

Author: Bruce Robbins <bersprockets@gmail.com>

Closes #21043 from bersprockets/tabreadfix.
2018-04-13 14:05:04 -07:00
..
catalyst [SPARK-23375][SQL] Eliminate unneeded Sort in Optimizer 2018-04-14 01:01:00 +08:00
core [SPARK-23375][SQL] Eliminate unneeded Sort in Optimizer 2018-04-14 01:01:00 +08:00
hive [SPARK-23963][SQL] Properly handle large number of columns in query on text-based Hive table 2018-04-13 14:05:04 -07:00
hive-thriftserver [SPARK-23639][SQL] Obtain token before init metastore client in SparkSQL CLI 2018-03-29 10:46:28 -07:00
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-21485][FOLLOWUP][SQL][DOCS] Describes examples and arguments separately, and note/since in SQL built-in function documentation 2017-08-05 10:10:56 -07:00
mkdocs.yml [SPARK-21485][SQL][DOCS] Spark SQL documentation generation for built-in functions 2017-07-26 09:38:51 -07:00
README.md [MINOR][DOC] Fix some typos and grammar issues 2018-04-06 13:37:08 +08:00

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 an extension of SQLContext called HiveContext that allows 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.