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Shixiong Zhu 15b144d2bf [SPARK-19617][SS] Fix the race condition when starting and stopping a query quickly 
## What changes were proposed in this pull request?

The streaming thread in StreamExecution uses the following ways to check if it should exit:
- Catch an InterruptException.
- `StreamExecution.state` is TERMINATED.

When starting and stopping a query quickly, the above two checks may both fail:
- Hit [HADOOP-14084](https://issues.apache.org/jira/browse/HADOOP-14084) and swallow InterruptException
- StreamExecution.stop is called before `state` becomes `ACTIVE`. Then [runBatches](dcc2d540a5/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala (L252)) changes the state from `TERMINATED` to `ACTIVE`.

If the above cases both happen, the query will hang forever.

This PR changes `state` to `AtomicReference` and uses`compareAndSet` to make sure we only change the state from `INITIALIZING` to `ACTIVE`. It also removes the `runUninterruptibly` hack from ``HDFSMetadata`, because HADOOP-14084 won't cause any problem after we fix the race condition.

## How was this patch tested?

Jenkins

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #16947 from zsxwing/SPARK-19617.
2017-02-17 19:04:45 -08:00
..
catalyst [SPARK-18352][SQL] Support parsing multiline json files 2017-02-16 20:51:19 -08:00
core [SPARK-19617][SS] Fix the race condition when starting and stopping a query quickly 2017-02-17 19:04:45 -08:00
hive [SPARK-19550][BUILD][CORE][WIP] Remove Java 7 support 2017-02-16 12:32:45 +00:00
hive-thriftserver [SPARK-18857][SQL] Don't use Iterator.duplicate for incrementalCollect in Thrift Server 2017-01-10 13:27:55 +00:00
README.md [SPARK-16557][SQL] Remove stale doc in sql/README.md 2016-07-14 19:24:42 -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 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.