b3d88ac029
## What changes were proposed in this pull request? Currently, the group state of user-defined-type is encoded as top-level columns in the UnsafeRows stores in the state store. The timeout timestamp is also saved as (when needed) as the last top-level column. Since the group state is serialized to top-level columns, you cannot save "null" as a value of state (setting null in all the top-level columns is not equivalent). So we don't let the user set the timeout without initializing the state for a key. Based on user experience, this leads to confusion. This PR is to change the row format such that the state is saved as nested columns. This would allow the state to be set to null, and avoid these confusing corner cases. However, queries recovering from existing checkpoint will use the previous format to maintain compatibility with existing production queries. ## How was this patch tested? Refactored existing end-to-end tests and added new tests for explicitly testing obj-to-row conversion for both state formats. Author: Tathagata Das <tathagata.das1565@gmail.com> Closes #21739 from tdas/SPARK-22187-1. |
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| .. | ||
| catalyst | ||
| core | ||
| hive | ||
| hive-thriftserver | ||
| create-docs.sh | ||
| gen-sql-markdown.py | ||
| mkdocs.yml | ||
| 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.