9348e68420
## What changes were proposed in this pull request? Some improvements: 1. Point out we are using both Spark SQ native syntax and HQL syntax in the example 2. Avoid using the same table name with temp view, to not confuse users. 3. Create the external hive table with a directory that already has data, which is a more common use case. 4. Remove the usage of `spark.sql.parquet.writeLegacyFormat`. This config was introduced by https://github.com/apache/spark/pull/8566 and has nothing to do with Hive. 5. Remove `repartition` and `coalesce` example. These 2 are not Hive specific, we should put them in a different example file. BTW they can't accurately control the number of output files, `spark.sql.files.maxRecordsPerFile` also controls it. ## How was this patch tested? N/A Author: Wenchen Fan <wenchen@databricks.com> Closes #20081 from cloud-fan/minor. |
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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 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.
Running sql/create-docs.sh
generates SQL documentation for built-in functions under sql/site
.