SPARK-3093 : masterLock in Worker is no longer need

there's no need to use masterLock in Worker now since all communications are within Akka actor

Author: CrazyJvm <crazyjvm@gmail.com>

Closes #2008 from CrazyJvm/no-need-master-lock and squashes the following commits:

dd39e20 [CrazyJvm] fix format
58e7fa5 [CrazyJvm] there's no need to use masterLock now since all communications are within Akka actor
[SPARK-2862] histogram method fails on some choices of bucketCount

Author: Chandan Kumar <chandan.kumar@imaginea.com>

Closes #1787 from nrchandan/spark-2862 and squashes the following commits:

a76bbf6 [Chandan Kumar] [SPARK-2862] Fix for a broken test case and add new test cases
4211eea [Chandan Kumar] [SPARK-2862] Add Scala bug id
13854f1 [Chandan Kumar] [SPARK-2862] Use shorthand range notation to avoid Scala bug
SPARK-3096: Include parquet hive serde by default in build

A small change - we should just add this dependency. It doesn't have any recursive deps and it's needed for reading have parquet tables.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #2009 from pwendell/parquet and squashes the following commits:

e411f9f [Patrick Wendell] SPARk-309: Include parquet hive serde by default in build
[SPARK-3084] [SQL] Collect broadcasted tables in parallel in joins

BroadcastHashJoin has a broadcastFuture variable that tries to collect
the broadcasted table in a separate thread, but this doesn't help
because it's a lazy val that only gets initialized when you attempt to
build the RDD. Thus queries that broadcast multiple tables would collect
and broadcast them sequentially. I changed this to a val to let it start
collecting right when the operator is created.

Author: Matei Zaharia <matei@databricks.com>

Closes #1990 from mateiz/spark-3084 and squashes the following commits:

f468766 [Matei Zaharia] [SPARK-3084] Collect broadcasted tables in parallel in joins
[SPARK-3085] [SQL] Use compact data structures in SQL joins

This reuses the CompactBuffer from Spark Core to save memory and pointer
dereferences. I also tried AppendOnlyMap instead of java.util.HashMap
but unfortunately that slows things down because it seems to do more
equals() calls and the equals on GenericRow, and especially JoinedRow,
is pretty expensive.

Author: Matei Zaharia <matei@databricks.com>

Closes #1993 from mateiz/spark-3085 and squashes the following commits:

188221e [Matei Zaharia] Remove unneeded import
5f903ee [Matei Zaharia] [SPARK-3085] [SQL] Use compact data structures in SQL joins
SPARK-3025 [SQL]: Allow JDBC clients to set a fair scheduler pool

This definitely needs review as I am not familiar with this part of Spark.
I tested this locally and it did seem to work.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #1937 from pwendell/scheduler and squashes the following commits:

b858e33 [Patrick Wendell] SPARK-3025: Allow JDBC clients to set a fair scheduler pool
[SPARK-3091] [SQL] Add support for caching metadata on Parquet files

For larger Parquet files, reading the file footers (which is done in parallel on up to 5 threads) and HDFS block locations (which is serial) can take multiple seconds. We can add an option to cache this data within FilteringParquetInputFormat. Unfortunately ParquetInputFormat only caches footers within each instance of ParquetInputFormat, not across them.

Note: this PR leaves this turned off by default for 1.1, but I believe it's safe to turn it on after. The keys in the hash maps are FileStatus objects that include a modification time, so this will work fine if files are modified. The location cache could become invalid if files have moved within HDFS, but that's rare so I just made it invalidate entries every 15 minutes.

Author: Matei Zaharia <matei@databricks.com>

Closes #2005 from mateiz/parquet-cache and squashes the following commits:

dae8efe [Matei Zaharia] Bug fix
c71e9ed [Matei Zaharia] Handle empty statuses directly
22072b0 [Matei Zaharia] Use Guava caches and add a config option for caching metadata
8fb56ce [Matei Zaharia] Cache file block locations too
453bd21 [Matei Zaharia] Bug fix
4094df6 [Matei Zaharia] First attempt at caching Parquet footers
[SPARK-2406][SQL] Initial support for using ParquetTableScan to read HiveMetaStore tables.

This PR adds an experimental flag `spark.sql.hive.convertMetastoreParquet` that when true causes the planner to detects tables that use Hive's Parquet SerDe and instead plans them using Spark SQL's native `ParquetTableScan`.

Author: Michael Armbrust <michael@databricks.com>
Author: Yin Huai <huai@cse.ohio-state.edu>

Closes #1819 from marmbrus/parquetMetastore and squashes the following commits:

1620079 [Michael Armbrust] Revert "remove hive parquet bundle"
cc30430 [Michael Armbrust] Merge remote-tracking branch 'origin/master' into parquetMetastore
4f3d54f [Michael Armbrust] fix style
41ebc5f [Michael Armbrust] remove hive parquet bundle
a43e0da [Michael Armbrust] Merge remote-tracking branch 'origin/master' into parquetMetastore
4c4dc19 [Michael Armbrust] Fix bug with tree splicing.
ebb267e [Michael Armbrust] include parquet hive to tests pass (Remove this later).
c0d9b72 [Michael Armbrust] Avoid creating a HadoopRDD per partition.  Add dirty hacks to retrieve partition values from the InputSplit.
8cdc93c [Michael Armbrust] Merge pull request #8 from yhuai/parquetMetastore
a0baec7 [Yin Huai] Partitioning columns can be resolved.
1161338 [Michael Armbrust] Add a test to make sure conversion is actually happening
212d5cd [Michael Armbrust] Initial support for using ParquetTableScan to read HiveMetaStore tables.
[SPARK-2169] Don't copy appName / basePath everywhere.

Instead of keeping copies in all pages, just reference the values
kept in the base SparkUI instance (by making them available via
getters).

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #1252 from vanzin/SPARK-2169 and squashes the following commits:

4412fc6 [Marcelo Vanzin] Simplify UIUtils.headerSparkPage signature.
4e5d35a [Marcelo Vanzin] [SPARK-2169] Don't copy appName / basePath everywhere.
Removed .travis.yml file since we are not using Travis.
[SPARK-3103] [PySpark] fix saveAsTextFile() with utf-8

bugfix: It will raise an exception when it try to encode non-ASCII strings into unicode. It should only encode unicode as "utf-8".

Author: Davies Liu <davies.liu@gmail.com>

Closes #2018 from davies/fix_utf8 and squashes the following commits:

4db7967 [Davies Liu] fix saveAsTextFile() with utf-8
[SPARK-2718] [yarn] Handle quotes and other characters in user args.

Due to the way Yarn runs things through bash, normal quoting doesn't
work as expected. This change applies the necessary voodoo to the user
args to avoid issues with bash and special characters.

The change also uncovered an issue with the event logger app name
sanitizing code; it wasn't cleaning up all "bad" characters, so
sometimes it would fail to create the log dirs. I just added some
more bad character replacements.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #1724 from vanzin/SPARK-2718 and squashes the following commits:

cc84b89 [Marcelo Vanzin] Review feedback.
c1a257a [Marcelo Vanzin] Add test for backslashes.
55571d4 [Marcelo Vanzin] Unbreak yarn-client.
515613d [Marcelo Vanzin] [SPARK-2718] [yarn] Handle quotes and other characters in user args.
[mllib] DecisionTree: treeAggregate + Python example bug fix

Small DecisionTree updates:
* Changed main DecisionTree aggregate to treeAggregate.
* Fixed bug in python example decision_tree_runner.py with missing argument (since categoricalFeaturesInfo is no longer an optional argument for trainClassifier).
* Fixed same bug in python doc tests, and added tree.py to doc tests.

CC: mengxr

Author: Joseph K. Bradley <joseph.kurata.bradley@gmail.com>

Closes #2015 from jkbradley/dt-opt2 and squashes the following commits:

b5114fa [Joseph K. Bradley] Fixed python tree.py doc test (extra newline)
8e4665d [Joseph K. Bradley] Added tree.py to python doc tests.  Fixed bug from missing categoricalFeaturesInfo argument.
b7b2922 [Joseph K. Bradley] Fixed bug in python example decision_tree_runner.py with missing argument.  Changed main DecisionTree aggregate to treeAggregate.
85bbc1f [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-opt2
66d076f [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-opt2
a0ed0da [Joseph K. Bradley] Renamed DTMetadata to DecisionTreeMetadata.  Small doc updates.
3726d20 [Joseph K. Bradley] Small code improvements based on code review.
ac0b9f8 [Joseph K. Bradley] Small updates based on code review. Main change: Now using << instead of math.pow.
db0d773 [Joseph K. Bradley] scala style fix
6a38f48 [Joseph K. Bradley] Added DTMetadata class for cleaner code
931a3a7 [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-opt2
797f68a [Joseph K. Bradley] Fixed DecisionTreeSuite bug for training second level.  Needed to update treePointToNodeIndex with groupShift.
f40381c [Joseph K. Bradley] Merge branch 'dt-opt1' into dt-opt2
5f2dec2 [Joseph K. Bradley] Fixed scalastyle issue in TreePoint
6b5651e [Joseph K. Bradley] Updates based on code review.  1 major change: persisting to memory + disk, not just memory.
2d2aaaf [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-opt1
26d10dd [Joseph K. Bradley] Removed tree/model/Filter.scala since no longer used.  Removed debugging println calls in DecisionTree.scala.
356daba [Joseph K. Bradley] Merge branch 'dt-opt1' into dt-opt2
430d782 [Joseph K. Bradley] Added more debug info on binning error.  Added some docs.
d036089 [Joseph K. Bradley] Print timing info to logDebug.
e66f1b1 [Joseph K. Bradley] TreePoint * Updated doc * Made some methods private
8464a6e [Joseph K. Bradley] Moved TimeTracker to tree/impl/ in its own file, and cleaned it up.  Removed debugging println calls from DecisionTree.  Made TreePoint extend Serialiable
a87e08f [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-opt1
c1565a5 [Joseph K. Bradley] Small DecisionTree updates: * Simplification: Updated calculateGainForSplit to take aggregates for a single (feature, split) pair. * Internal doc: findAggForOrderedFeatureClassification
b914f3b [Joseph K. Bradley] DecisionTree optimization: eliminated filters + small changes
b2ed1f3 [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-opt
0f676e2 [Joseph K. Bradley] Optimizations + Bug fix for DecisionTree
3211f02 [Joseph K. Bradley] Optimizing DecisionTree * Added TreePoint representation to avoid calling findBin multiple times. * (not working yet, but debugging)
f61e9d2 [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-timing
bcf874a [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-timing
511ec85 [Joseph K. Bradley] Merge remote-tracking branch 'upstream/master' into dt-timing
a95bc22 [Joseph K. Bradley] timing for DecisionTree internals