[SPARK-2805] Upgrade to akka 2.3.4

Upgrade to akka 2.3.4

Author: Anand Avati <avati@redhat.com>

Closes #1685 from avati/SPARK-1812-akka-2.3 and squashes the following commits:

57a2315 [Anand Avati] SPARK-1812: streaming - remove tests which depend on akka.actor.IO
2a551d3 [Anand Avati] SPARK-1812: core - upgrade to akka 2.3.4
[SPARK-3844][UI] Truncate appName in WebUI if it is too long

Truncate appName in WebUI if it is too long.

Author: Xiangrui Meng <meng@databricks.com>

Closes #2707 from mengxr/truncate-app-name and squashes the following commits:

87834ce [Xiangrui Meng] move scala import below java
c7111dc [Xiangrui Meng] truncate appName in WebUI if it is too long
add spark.driver.memory to config docs

It took me a minute to track this down, so I thought it could be useful to have it in the docs.

I'm unsure if 512mb is the default for spark.driver.memory? Also - there could be a better value for the 'description' to differentiate it from spark.executor.memory.

Author: nartz <nartzpod@gmail.com>
Author: Nathan Artz <nathanartz@Nathans-MacBook-Pro.local>

Closes #2410 from nartz/docs/add-spark-driver-memory-to-config-docs and squashes the following commits:

a2f6c62 [nartz] Update configuration.md
74521b8 [Nathan Artz] add spark.driver.memory to config docs
[SPARK-3158][MLLIB]Avoid 1 extra aggregation for DecisionTree training

Currently, the implementation does one unnecessary aggregation step. The aggregation step for level L (to choose splits) gives enough information to set the predictions of any leaf nodes at level L+1. We can use that info and skip the aggregation step for the last level of the tree (which only has leaf nodes).

### Implementation Details

Each node now has a `impurity` field and the `predict` is changed from type `Double` to type `Predict`(this can be used to compute predict probability in the future) When compute best splits for each node, we also compute impurity and predict for the child nodes, which is used to constructed newly allocated child nodes. So at level L, we have set impurity and predict for nodes at level L +1.
If level L+1 is the last level, then we can avoid aggregation. What's more, calculation of parent impurity in

Top nodes for each tree needs to be treated differently because we have to compute impurity and predict for them first. In `binsToBestSplit`, if current node is top node(level == 0), we calculate impurity and predict first.
after finding best split, top node's predict and impurity is set to the calculated value. Non-top nodes's impurity and predict are already calculated and don't need to be recalculated again. I have considered to add a initialization step to set top nodes' impurity and predict and then we can treat all nodes in the same way, but this will need a lot of duplication of code(all the code to do seq operation(BinSeqOp) needs to be duplicated), so I choose the current way.

 CC mengxr manishamde jkbradley, please help me review this, thanks.

Author: Qiping Li <liqiping1991@gmail.com>

Closes #2708 from chouqin/avoid-agg and squashes the following commits:

8e269ea [Qiping Li] adjust code and comments
eefeef1 [Qiping Li] adjust comments and check child nodes' impurity
c41b1b6 [Qiping Li] fix pyspark unit test
7ad7a71 [Qiping Li] fix unit test
822c912 [Qiping Li] add comments and unit test
e41d715 [Qiping Li] fix bug in test suite
6cc0333 [Qiping Li] SPARK-3158: Avoid 1 extra aggregation for DecisionTree training
[Minor] use norm operator after breeze 0.10 upgrade

cc mengxr

Author: GuoQiang Li <witgo@qq.com>

Closes #2730 from witgo/SPARK-3856 and squashes the following commits:

2cffce1 [GuoQiang Li] use norm operator after breeze 0.10 upgrade
[SPARK-3741] Make ConnectionManager propagate errors properly and add mo...

...re logs to avoid Executors swallowing errors

This PR made the following changes:
* Register a callback to `Connection` so that the error will be propagated properly.
* Add more logs so that the errors won't be swallowed by Executors.
* Use trySuccess/tryFailure because `Promise` doesn't allow to call success/failure more than once.

Author: zsxwing <zsxwing@gmail.com>

Closes #2593 from zsxwing/SPARK-3741 and squashes the following commits:

1d5aed5 [zsxwing] Fix naming
0b8a61c [zsxwing] Merge branch 'master' into SPARK-3741
764aec5 [zsxwing] [SPARK-3741] Make ConnectionManager propagate errors properly and add more logs to avoid Executors swallowing errors
[SPARK-3752][SQL]: Add tests for different UDF's

Author: Vida Ha <vida@databricks.com>

Closes #2621 from vidaha/vida/SPARK-3752 and squashes the following commits:

d7fdbbc [Vida Ha] Add tests for different UDF's
[SPARK-3711][SQL] Optimize where in clause filter queries

The In case class is replaced by a InSet class in case all the filters are literals, which uses a hashset instead of Sequence, thereby giving significant performance improvement (earlier the seq was using a worst case linear match (exists method) since expressions were assumed in the filter list) . Maximum improvement should be visible in case small percentage of large data matches the filter list.

Author: Yash Datta <Yash.Datta@guavus.com>

Closes #2561 from saucam/branch-1.1 and squashes the following commits:

4bf2d19 [Yash Datta] SPARK-3711: 1. Fix code style and import order             2. Fix optimization condition             3. Add tests for null in filter list             4. Add test case that optimization is not triggered in case of attributes in filter list
afedbcd [Yash Datta] SPARK-3711: 1. Add test cases for InSet class in ExpressionEvaluationSuite             2. Add class OptimizedInSuite on the lines of ConstantFoldingSuite, for the optimized In clause
0fc902f [Yash Datta] SPARK-3711: UnaryMinus will be handled by constantFolding
bd84c67 [Yash Datta] SPARK-3711: Incorporate review comments. Move optimization of In clause to Optimizer.scala by adding a rule. Add appropriate comments
430f5d1 [Yash Datta] SPARK-3711: Optimize the filter list in case of negative values as well
bee98aa [Yash Datta] SPARK-3711: Optimize where in clause filter queries
[SPARK-3806][SQL] Minor fix for CliSuite

To fix two issues in CliSuite
1 CliSuite throw IndexOutOfBoundsException:
Exception in thread "Thread-6" java.lang.IndexOutOfBoundsException: 6
	at scala.collection.mutable.ResizableArray$class.apply(ResizableArray.scala:43)
	at scala.collection.mutable.ArrayBuffer.apply(ArrayBuffer.scala:47)
	at org.apache.spark.sql.hive.thriftserver.CliSuite.org$apache$spark$sql$hive$thriftserver$CliSuite$$captureOutput$1(CliSuite.scala:67)
	at org.apache.spark.sql.hive.thriftserver.CliSuite$$anonfun$4.apply(CliSuite.scala:78)
	at org.apache.spark.sql.hive.thriftserver.CliSuite$$anonfun$4.apply(CliSuite.scala:78)
	at scala.sys.process.ProcessLogger$$anon$1.out(ProcessLogger.scala:96)
	at scala.sys.process.BasicIO$$anonfun$processOutFully$1.apply(BasicIO.scala:135)
	at scala.sys.process.BasicIO$$anonfun$processOutFully$1.apply(BasicIO.scala:135)
	at scala.sys.process.BasicIO$.readFully$1(BasicIO.scala:175)
	at scala.sys.process.BasicIO$.processLinesFully(BasicIO.scala:179)
	at scala.sys.process.BasicIO$$anonfun$processFully$1.apply(BasicIO.scala:164)
	at scala.sys.process.BasicIO$$anonfun$processFully$1.apply(BasicIO.scala:162)
	at scala.sys.process.ProcessBuilderImpl$Simple$$anonfun$3.apply$mcV$sp(ProcessBuilderImpl.scala:73)
	at scala.sys.process.ProcessImpl$Spawn$$anon$1.run(ProcessImpl.scala:22)

Actually, it is the Mutil-Threads lead to this problem.

2 Using ```line.startsWith``` instead ```line.contains``` to assert expected answer. This is a tiny bug in CliSuite, for test case "Simple commands", there is a expected answers "5", if we use ```contains``` that means output like "14/10/06 11:```5```4:36 INFO CliDriver: Time taken: 1.078 seconds" or "14/10/06 11:54:36 INFO StatsReportListener: 	0%	```5```%	10%	25%	50%	75%	90%	95%	100%" will make the assert true.

Author: scwf <wangfei1@huawei.com>

Closes #2666 from scwf/clisuite and squashes the following commits:

11430db [scwf] fix-clisuite
[SPARK-3868][PySpark] Hard to recognize which module is tested from unit-tests.log

./python/run-tests script display messages about which test it is running currently on stdout but not write them on unit-tests.log.
It is harder for us to recognize what test programs were executed and which test was failed.

Author: cocoatomo <cocoatomo77@gmail.com>

Closes #2724 from cocoatomo/issues/3868-display-testing-module-name and squashes the following commits:

c63d9fa [cocoatomo] [SPARK-3868][PySpark] Hard to recognize which module is tested from unit-tests.log
[SPARK-3853][SQL] JSON Schema support for Timestamp fields

In JSONRDD.scala, add 'case TimestampType' in the enforceCorrectType function and a toTimestamp function.

Author: Mike Timper <mike@aurorafeint.com>

Closes #2720 from mtimper/master and squashes the following commits:

9386ab8 [Mike Timper] Fix and tests for SPARK-3853
Revert "[SPARK-2805] Upgrade to akka 2.3.4"

This reverts commit b9df8af62e8d7b263a668dfb6e9668ab4294ea37.
[SPARK-3339][SQL] Support for skipping json lines that fail to parse

This PR aims to provide a way to skip/query corrupt JSON records. To do so, we introduce an internal column to hold corrupt records (the default name is `_corrupt_record`. This name can be changed by setting the value of `spark.sql.columnNameOfCorruptRecord`). When there is a parsing error, we will put the corrupt record in its unparsed format to the internal column. Users can skip/query this column through SQL.

* To query those corrupt records
```
-- For Hive parser
SELECT `_corrupt_record`
FROM jsonTable
WHERE `_corrupt_record` IS NOT NULL
-- For our SQL parser
SELECT _corrupt_record
FROM jsonTable
WHERE _corrupt_record IS NOT NULL
```
* To skip corrupt records and query regular records
```
-- For Hive parser
SELECT field1, field2
FROM jsonTable
WHERE `_corrupt_record` IS NULL
-- For our SQL parser
SELECT field1, field2
FROM jsonTable
WHERE _corrupt_record IS NULL
```

Generally, it is not recommended to change the name of the internal column. If the name has to be changed to avoid possible name conflicts, you can use `sqlContext.setConf(SQLConf.COLUMN_NAME_OF_CORRUPT_RECORD, <new column name>)` or `sqlContext.sql(SET spark.sql.columnNameOfCorruptRecord=<new column name>)`.

Author: Yin Huai <huai@cse.ohio-state.edu>

Closes #2680 from yhuai/corruptJsonRecord and squashes the following commits:

4c9828e [Yin Huai] Merge remote-tracking branch 'upstream/master' into corruptJsonRecord
309616a [Yin Huai] Change the default name of corrupt record to "_corrupt_record".
b4a3632 [Yin Huai] Merge remote-tracking branch 'upstream/master' into corruptJsonRecord
9375ae9 [Yin Huai] Set the column name of corrupt json record back to the default one after the unit test.
ee584c0 [Yin Huai] Provide a way to query corrupt json records as unparsed strings.
[SPARK-3412][SQL]add missing row api

chenghao-intel assigned this to me, check PR #2284 for previous discussion

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #2529 from adrian-wang/rowapi and squashes the following commits:

c6594b2 [Daoyuan Wang] using boxed
7b7e6e3 [Daoyuan Wang] update pattern match
7a39456 [Daoyuan Wang] rename file and refresh getAs[T]
4c18c29 [Daoyuan Wang] remove setAs[T] and null judge
1614493 [Daoyuan Wang] add missing row api
[SPARK-3858][SQL] Pass the generator alias into logical plan node

The alias parameter is being ignored, which makes it more difficult to specify a qualifier for Generator expressions.

Author: Nathan Howell <nhowell@godaddy.com>

Closes #2721 from NathanHowell/SPARK-3858 and squashes the following commits:

8aa0f43 [Nathan Howell] [SPARK-3858][SQL] Pass the generator alias into logical plan node
[SPARK-3813][SQL] Support "case when" conditional functions in Spark SQL.

"case when" conditional function is already supported in Spark SQL but there is no support in SqlParser. So added parser support to it.

Author : ravipesala ravindra.pesalahuawei.com

Author: ravipesala <ravindra.pesala@huawei.com>

Closes #2678 from ravipesala/SPARK-3813 and squashes the following commits:

70c75a7 [ravipesala] Fixed styles
713ea84 [ravipesala] Updated as per admin comments
709684f [ravipesala] Changed parser to support case when function.
[SPARK-3772] Allow `ipython` to be used by Pyspark workers; IPython support improvements:

This pull request addresses a few issues related to PySpark's IPython support:

- Fix the remaining uses of the '-u' flag, which IPython doesn't support (see SPARK-3772).
- Change PYSPARK_PYTHON_OPTS to PYSPARK_DRIVER_PYTHON_OPTS, so that the old name is reserved in case we ever want to allow the worker Python options to be customized (this variable was introduced in #2554 and hasn't landed in a release yet, so this doesn't break any compatibility).
- Introduce a PYSPARK_DRIVER_PYTHON option that allows the driver to use `ipython` while the workers use a different Python version.
- Attempt to use Python 2.7 by default if PYSPARK_PYTHON is not specified.
- Retain the old semantics for IPYTHON=1 and IPYTHON_OPTS (to avoid breaking existing example programs).

There are more details in a block comment in `bin/pyspark`.

Author: Josh Rosen <joshrosen@apache.org>

Closes #2651 from JoshRosen/SPARK-3772 and squashes the following commits:

7b8eb86 [Josh Rosen] More changes to PySpark python executable configuration:
c4f5778 [Josh Rosen] [SPARK-3772] Allow ipython to be used by Pyspark workers; IPython fixes:
[SPARK-3798][SQL] Store the output of a generator in a val

This prevents it from changing during serialization, leading to corrupted results.

Author: Michael Armbrust <michael@databricks.com>

Closes #2656 from marmbrus/generateBug and squashes the following commits:

efa32eb [Michael Armbrust] Store the output of a generator in a val. This prevents it from changing during serialization.
SPARK-3811 [CORE] More robust / standard Utils.deleteRecursively, Utils.createTempDir

I noticed a few issues with how temp directories are created and deleted:

*Minor*

* Guava's `Files.createTempDir()` plus `File.deleteOnExit()` is used in many tests to make a temp dir, but `Utils.createTempDir()` seems to be the standard Spark mechanism
* Call to `File.deleteOnExit()` could be pushed into `Utils.createTempDir()` as well, along with this replacement
* _I messed up the message in an exception in `Utils` in SPARK-3794; fixed here_

*Bit Less Minor*

* `Utils.deleteRecursively()` fails immediately if any `IOException` occurs, instead of trying to delete any remaining files and subdirectories. I've observed this leave temp dirs around. I suggest changing it to continue in the face of an exception and throw one of the possibly several exceptions that occur at the end.
* `Utils.createTempDir()` will add a JVM shutdown hook every time the method is called. Even if the subdir is the parent of another parent dir, since this check is inside the hook. However `Utils` manages a set of all dirs to delete on shutdown already, called `shutdownDeletePaths`. A single hook can be registered to delete all of these on exit. This is how Tachyon temp paths are cleaned up in `TachyonBlockManager`.

I noticed a few other things that might be changed but wanted to ask first:

* Shouldn't the set of dirs to delete be `File`, not just `String` paths?
* `Utils` manages the set of `TachyonFile` that have been registered for deletion, but the shutdown hook is managed in `TachyonBlockManager`. Should this logic not live together, and not in `Utils`? it's more specific to Tachyon, and looks a slight bit odd to import in such a generic place.

Author: Sean Owen <sowen@cloudera.com>

Closes #2670 from srowen/SPARK-3811 and squashes the following commits:

071ae60 [Sean Owen] Update per @vanzin's review
da0146d [Sean Owen] Make Utils.deleteRecursively try to delete all paths even when an exception occurs; use one shutdown hook instead of one per method call to delete temp dirs
3a0faa4 [Sean Owen] Standardize on Utils.createTempDir instead of Files.createTempDir
[SPARK-3654][SQL] Unifies SQL and HiveQL parsers

This PR is a follow up of #2590, and tries to introduce a top level SQL parser entry point for all SQL dialects supported by Spark SQL.

A top level parser `SparkSQLParser` is introduced to handle the syntaxes that all SQL dialects should recognize (e.g. `CACHE TABLE`, `UNCACHE TABLE` and `SET`, etc.). For all the syntaxes this parser doesn't recognize directly, it fallbacks to a specified function that tries to parse arbitrary input to a `LogicalPlan`. This function is typically another parser combinator like `SqlParser`. DDL syntaxes introduced in #2475 can be moved to here.

The `ExtendedHiveQlParser` now only handle Hive specific extensions.

Also took the chance to refactor/reformat `SqlParser` for better readability.

Author: Cheng Lian <lian.cs.zju@gmail.com>

Closes #2698 from liancheng/gen-sql-parser and squashes the following commits:

ceada76 [Cheng Lian] Minor styling fixes
9738934 [Cheng Lian] Minor refactoring, removes optional trailing ";" in the parser
bb2ab12 [Cheng Lian] SET property value can be empty string
ce8860b [Cheng Lian] Passes test suites
e86968e [Cheng Lian] Removes debugging code
8bcace5 [Cheng Lian] Replaces digit.+ to rep1(digit) (Scala style checking doesn't like it)
d15d54f [Cheng Lian] Unifies SQL and HiveQL parsers