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Steve Loughran 02fa19f102 [SPARK-33230][SQL] Hadoop committers to get unique job ID in "spark.sql.sources.writeJobUUID" 
### What changes were proposed in this pull request?

This reinstates the old option `spark.sql.sources.write.jobUUID` to set a unique jobId in the jobconf so that hadoop MR committers have a unique ID which is (a) consistent across tasks and workers and (b) not brittle compared to generated-timestamp job IDs. The latter matches that of what JobID requires, but as they are generated per-thread, may not always be unique within a cluster.

### Why are the changes needed?

If a committer (e.g s3a staging committer) uses job-attempt-ID as a unique ID then any two jobs started within the same second have the same ID, so can clash.

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

Good Q. It is "developer-facing" in the context of anyone writing a committer. But it reinstates a property which was in Spark 1.x and "went away"

### How was this patch tested?

Testing: no test here. You'd have to create a new committer which extracted the value in both job and task(s) and verified consistency. That is possible (with a task output whose records contained the UUID), but it would be pretty convoluted and a high maintenance cost.

Because it's trying to address a race condition, it's hard to regenerate the problem downstream and so verify a fix in a test run...I'll just look at the logs to see what temporary dir is being used in the cluster FS and verify it's a UUID

Closes #30141 from steveloughran/SPARK-33230-jobId.

Authored-by: Steve Loughran <stevel@cloudera.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2020-10-26 12:31:05 -07:00
..
catalyst [SPARK-33075][SQL] Enable auto bucketed scan by default (disable only for cached query) 2020-10-26 20:23:24 +09:00
core [SPARK-33230][SQL] Hadoop committers to get unique job ID in "spark.sql.sources.writeJobUUID" 2020-10-26 12:31:05 -07:00
hive Revert "[SPARK-32388][SQL] TRANSFORM with schema-less mode should keep the same with hive" 2020-10-26 11:38:48 +09:00
hive-thriftserver [SPARK-33193][SQL][TEST] Hive ThriftServer JDBC Database MetaData API Behavior Auditing 2020-10-23 13:34:33 -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.