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## What changes were proposed in this pull request? On CREATE/ALTER a view, it's no longer needed to generate a SQL text string from the LogicalPlan, instead we store the SQL query text、the output column names of the query plan, and current database to CatalogTable. Permanent views created by this approach can be resolved by current view resolution approach. The main advantage includes: 1. If you update an underlying view, the current view also gets updated; 2. That gives us a change to get ride of SQL generation for operators. Major changes of this PR: 1. Generate the view-specific properties(e.g. view default database, view query output column names) during permanent view creation and store them as properties in the CatalogTable; 2. Update the commands `CreateViewCommand` and `AlterViewAsCommand`, get rid of SQL generation from them. ## How was this patch tested? Existing tests. Author: jiangxingbo <jiangxb1987@gmail.com> Closes #16613 from jiangxb1987/view-write-path. |
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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 allows 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.