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Yuanjian Li 2d9cc42aa8 [SPARK-28699][SQL] Disable using radix sort for ShuffleExchangeExec in repartition case 
## What changes were proposed in this pull request?

Disable using radix sort in ShuffleExchangeExec when we do repartition.
In #20393, we fixed the indeterministic result in the shuffle repartition case by performing a local sort before repartitioning.
But for the newly added sort operation, we use radix sort which is wrong because binary data can't be compared by only the prefix. This makes the sort unstable and fails to solve the indeterminate shuffle output problem.

### Why are the changes needed?
Fix the correctness bug caused by repartition after a shuffle.

### Does this PR introduce any user-facing change?
Yes, user will get the right result in the case of repartition stage rerun.

## How was this patch tested?

Test with `local-cluster[5, 2, 5120]`, use the integrated test below, it can return a right answer 100000000.
```
import scala.sys.process._
import org.apache.spark.TaskContext

val res = spark.range(0, 10000 * 10000, 1).map{ x => (x % 1000, x)}
// kill an executor in the stage that performs repartition(239)
val df = res.repartition(113).map{ x => (x._1 + 1, x._2)}.repartition(239).map { x =>
  if (TaskContext.get.attemptNumber == 0 && TaskContext.get.partitionId < 1 && TaskContext.get.stageAttemptNumber == 0) {
    throw new Exception("pkill -f -n java".!!)
  }
  x
}
val r2 = df.distinct.count()
```

Closes #25491 from xuanyuanking/SPARK-28699-fix.

Authored-by: Yuanjian Li <xyliyuanjian@gmail.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2019-08-21 10:56:50 -07:00
..
catalyst [SPARK-28715][SQL] Introduce collectInPlanAndSubqueries and subqueriesAll in QueryPlan 2019-08-21 18:05:18 +02:00
core [SPARK-28699][SQL] Disable using radix sort for ShuffleExchangeExec in repartition case 2019-08-21 10:56:50 -07:00
hive [SPARK-28635][SQL] create CatalogManager to track registered v2 catalogs 2019-08-20 19:40:21 +08:00
hive-thriftserver Revert "[SPARK-28527][SQL][TEST] Re-run all the tests in SQLQueryTestSuite via Thrift Server" 2019-08-18 16:54:24 -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-27328][SQL] Add 'deprecated' in ExpressionDescription for extended usage and SQL doc 2019-04-09 13:49:42 +08:00
mkdocs.yml [SPARK-21485][SQL][DOCS] Spark SQL documentation generation for built-in functions 2017-07-26 09:38:51 -07:00
README.md [SPARK-28473][DOC] Stylistic consistency of build command in README 2019-07-23 16:29:46 -07:00

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.