Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #7237 from cloud-fan/parser and squashes the following commits:

e7b49bb [Wenchen Fan] support using keyword in column name

Here are more examples on SparkR DataFrames including creating a Spark Contect and a SQL
context, loading data and simple data manipulation.

Author: Daniel Emaasit (PhD Student) <daniel.emaasit@gmail.com>

Closes #6668 from Emaasit/dan-dev and squashes the following commits:

3a97867 [Daniel Emaasit (PhD Student)] Used fewer rows for createDataFrame
f7227f9 [Daniel Emaasit (PhD Student)] Using command line arguments
a550f70 [Daniel Emaasit (PhD Student)] Used base R functions
33f9882 [Daniel Emaasit (PhD Student)] Renamed file
b6603e3 [Daniel Emaasit (PhD Student)] changed "Describe" function to "describe"
90565dd [Daniel Emaasit (PhD Student)] Deleted the getting-started file
b95a103 [Daniel Emaasit (PhD Student)] Deleted this file
cc55cd8 [Daniel Emaasit (PhD Student)] combined all the code into one .R file
c6933af [Daniel Emaasit (PhD Student)] changed variable name to SQLContext
8e0fe14 [Daniel Emaasit (PhD Student)] provided two options for creating DataFrames
2653573 [Daniel Emaasit (PhD Student)] Updates to a comment and variable name
275b787 [Daniel Emaasit (PhD Student)] Added the Apache License at the top of the file
2e8f724 [Daniel Emaasit (PhD Student)] Added the Apache License at the top of the file
486f44e [Daniel Emaasit (PhD Student)] Added the Apache License at the file
d705112 [Daniel Emaasit (PhD Student)] Created more examples on SparkR DataFrames

When pruning partitions for a query plan, a message is logged indicating what how many partitions were selected based on predicate criteria, and what percent were pruned.

The current release erroneously uses `1 - total/selected` to compute this quantity, leading to nonsense messages like "pruned -1000% partitions". The fix is simple and obvious.

Author: Steve Lindemann <steve.lindemann@engineersgatelp.com>

Closes #7227 from srlindemann/master and squashes the following commits:

c788061 [Steve Lindemann] fix percentPruned log message

Otherwise it is impossible to declare an expression supporting DecimalType.

Author: Reynold Xin <rxin@databricks.com>

Closes #7232 from rxin/typecollection-adt and squashes the following commits:

934d3d1 [Reynold Xin] [SPARK-8831][SQL] Support AbstractDataType in TypeCollection.

This is a the follow up of #6843.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #7230 from chenghao-intel/str_funcs2_followup and squashes the following commits:

52cc553 [Cheng Hao] update the code as comment

[[SPARK-8549] Fix the line length of SparkR - ASF JIRA](https://issues.apache.org/jira/browse/SPARK-8549)

Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>

Closes #7204 from yu-iskw/SPARK-8549 and squashes the following commits:

6fb131a [Yu ISHIKAWA] Fix the typo
1737598 [Yu ISHIKAWA] [SPARK-8549][SparkR] Fix the line length of SparkR

Author: Joshi <rekhajoshm@gmail.com>
Author: Rekha Joshi <rekhajoshm@gmail.com>

Closes #5992 from rekhajoshm/fix/SPARK-7137 and squashes the following commits:

8c42b57 [Joshi] update checkInputColumn to print more info if needed
33ddd2e [Joshi] update checkInputColumn to print more info if needed
acf3e17 [Joshi] update checkInputColumn to print more info if needed
8993c0e [Joshi] SPARK-7137: Add checkInputColumn back to Params and print more info
e3677c9 [Rekha Joshi] Merge pull request #1 from apache/master

ping liancheng

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #7224 from viirya/few_fix_catalystschema and squashes the following commits:

d994330 [Liang-Chi Hsieh] Minor fix for CatalystSchemaConverter.

Author: Reynold Xin <rxin@databricks.com>

Closes #7220 from rxin/SPARK-8822 and squashes the following commits:

0cda076 [Reynold Xin] Test cases.
22d0463 [Reynold Xin] Fixed type precedence.
beb2a97 [Reynold Xin] [SPARK-8822][SQL] clean up type checking in math.scala.

Author: Reynold Xin <rxin@databricks.com>

Closes #7221 from rxin/implicit-cast-tests and squashes the following commits:

64b13bd [Reynold Xin] Fixed a bug ..
489b732 [Reynold Xin] [SQL] More unit tests for implicit type cast & add simpleString to AbstractDataType.

Jira: https://issues.apache.org/jira/browse/SPARK-8270

Info: I can not build the latest master, it stucks during the build process: `[INFO] Dependency-reduced POM written at: /Users/tarek/test/spark/bagel/dependency-reduced-pom.xml`

Author: Tarek Auel <tarek.auel@googlemail.com>

Closes #7214 from tarekauel/SPARK-8270 and squashes the following commits:

ab348b9 [Tarek Auel] Merge branch 'master' into SPARK-8270
a2ad318 [Tarek Auel] [SPARK-8270] changed order of fields
d91b12c [Tarek Auel] [SPARK-8270] python fix
adbd075 [Tarek Auel] [SPARK-8270] fixed typo
23185c9 [Tarek Auel] [SPARK-8270] levenshtein distance

[SPARK-8238][SPARK-8239][SPARK-8242][SPARK-8243][SPARK-8268][SQL]Add ascii/base64/unbase64/encode/decode functions

Add `ascii`,`base64`,`unbase64`,`encode` and `decode` expressions.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #6843 from chenghao-intel/str_funcs2 and squashes the following commits:

78dee7d [Cheng Hao] base 64 -> base64
9d6f9f4 [Cheng Hao] remove the toString method for expressions
ed5c19c [Cheng Hao] update code as comments
96170fc [Cheng Hao] scalastyle issues
e2df768 [Cheng Hao] remove the unused import
491ce7b [Cheng Hao] add ascii/base64/unbase64/encode/decode functions

This commit adds a set of random data generation utilities to Spark SQL, for use in its own unit tests.

- `RandomDataGenerator.forType(DataType)` returns an `Option[() => Any]` that, if defined, contains a function for generating random values for the given DataType.  The random values use the external representations for the given DataType (for example, for DateType we return `java.sql.Date` instances instead of longs).
- `DateTypeTestUtilities` defines some convenience fields for looping over instances of data types.  For example, `numericTypes` holds `DataType` instances for all supported numeric types.  These constants will help us to raise the level of abstraction in our tests.  For example, it's now very easy to write a test which is parameterized by all common data types.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #7176 from JoshRosen/sql-random-data-generators and squashes the following commits:

f71634d [Josh Rosen] Roll back ScalaCheck usage
e0d7d49 [Josh Rosen] Bump ScalaCheck version in LICENSE
89d86b1 [Josh Rosen] Bump ScalaCheck version.
0c20905 [Josh Rosen] Initial attempt at using ScalaCheck.
b55875a [Josh Rosen] Generate doubles and floats over entire possible range.
5acdd5c [Josh Rosen] Infinity and NaN are interesting.
ab76cbd [Josh Rosen] Move code to Catalyst package.
d2b4a4a [Josh Rosen] Add random data generator test utilities to Spark SQL.

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

Closes #6985 from adrian-wang/udfcurrent and squashes the following commits:

6a20b64 [Daoyuan Wang] remove codegen and add lazy in testsuite
27c9f95 [Daoyuan Wang] refine tests..
e11ae75 [Daoyuan Wang] refine tests
61ed3d5 [Daoyuan Wang] add in functions
98e8550 [Daoyuan Wang] fix sytle
427d9dc [Daoyuan Wang] add tests and codegen
0b69a1f [Daoyuan Wang] udf current

Implemented type coercion for udf arguments in Scala. The changes include-
* Add `with ExpectsInputTypes ` to `ScalaUDF` class.
* Pass down argument types info from `UDFRegistration` and `functions`.

With this patch, the example query in [SPARK-8572](https://issues.apache.org/jira/browse/SPARK-8572) no longer throws a type cast error at runtime.

Also added a unit test to `UDFSuite` in which a decimal type is passed to a udf that expects an int.

Author: Cheolsoo Park <cheolsoop@netflix.com>

Closes #7203 from piaozhexiu/SPARK-8572 and squashes the following commits:

2d0ed15 [Cheolsoo Park] Incorporate comments
dce1efd [Cheolsoo Park] Fix unit tests and update the codegen script
066deed [Cheolsoo Park] Type coercion for udf inputs

One test for each of the GROUP BY, WHERE and HAVING clauses, and one that combines all three with an additional UDF in the SELECT.

(Since this is my first attempt at contributing to SPARK, meta-level guidance on anything I've screwed up would be greatly appreciated, whether important or minor.)

Author: Spiro Michaylov <spiro@michaylov.com>

Closes #7207 from spirom/udf-test-branch and squashes the following commits:

6bbba9e [Spiro Michaylov] Responded to review comments on UDF unit tests
1a3c5ff [Spiro Michaylov] Added several UDF unit tests for Spark SQL

[SPARK-7401] [MLLIB] [PYSPARK] Vectorize dot product and sq_dist between SparseVector and DenseVector

Currently we iterate over indices which can be vectorized.

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #5946 from MechCoder/spark-7203 and squashes the following commits:

034d086 [MechCoder] Vectorize dot calculation for numpy arrays for ndim=2
bce2b07 [MechCoder] fix doctest
fcad0a3 [MechCoder] Remove type checks for list, pyarray etc
0ee5dd4 [MechCoder] Add tests and other isinstance changes
e5f1de0 [MechCoder] [SPARK-7401] Vectorize dot product and sq_dist

Author: zhichao.li <zhichao.li@intel.com>

Closes #7035 from zhichao-li/shiftRightUnsigned and squashes the following commits:

6bcca5a [zhichao.li] change coding style
3e9f5ae [zhichao.li] python style
d85ae0b [zhichao.li] add shiftrightunsigned

"NaN" from string to double is already handled by Cast expression itself.

Author: Reynold Xin <rxin@databricks.com>

Closes #7206 from rxin/convertnans and squashes the following commits:

3d99c33 [Reynold Xin] [SPARK-8809][SQL] Remove ConvertNaNs analyzer rule.

cc rxin

Having back ticks or null as elements causes problems.
Since elements become column names, we have to drop them from the element as back ticks are special characters.
Having null throws exceptions, we could replace them with empty strings.

Handling back ticks should be improved for 1.5

Author: Burak Yavuz <brkyvz@gmail.com>

Closes #7201 from brkyvz/weird-ct-elements and squashes the following commits:

e06b840 [Burak Yavuz] fix scalastyle
93a0d3f [Burak Yavuz] added tests for NaN and Infinity
9dba6ce [Burak Yavuz] address cr1
db71dbd [Burak Yavuz] handle special characters in elements in crosstab

I am increasing the perm gen size to 256m.

https://issues.apache.org/jira/browse/SPARK-8776

Author: Yin Huai <yhuai@databricks.com>

Closes #7196 from yhuai/SPARK-8776 and squashes the following commits:

60901b4 [Yin Huai] Fix test.
d44b713 [Yin Huai] Make sparkShell and hiveConsole use 256m PermGen size.
30aaf8e [Yin Huai] Increase the default PermGen size to 256m.

This patch adds a new TypeCollection AbstractDataType that can be used by expressions to specify more than one expected input types.

Author: Reynold Xin <rxin@databricks.com>

Closes #7202 from rxin/type-collection and squashes the following commits:

c714ca1 [Reynold Xin] Fixed style.
a0c0d12 [Reynold Xin] Fixed bugs and unit tests.
d8b8ae7 [Reynold Xin] Added TypeCollection.

ORC writes empty schema (`struct<>`) to ORC files containing zero rows.  This is OK for Hive since the table schema is managed by the metastore. But it causes trouble when reading raw ORC files via Spark SQL since we have to discover the schema from the files.

Notice that the ORC data source always avoids writing empty ORC files, but it's still problematic when reading Hive tables which contain empty part-files.

Author: Cheng Lian <lian@databricks.com>

Closes #7199 from liancheng/spark-8501 and squashes the following commits:

bb8cd95 [Cheng Lian] Addresses comments
a290221 [Cheng Lian] Avoids reading schema from empty ORC files

Author: zhichao.li <zhichao.li@intel.com>

Closes #6822 from zhichao-li/factorial and squashes the following commits:

26edf4f [zhichao.li] add factorial

Latest changes after refactoring to the RPC layer.  I rebased against trunk to make sure to get any recent changes since it had been a while.  I wasn't crazy about the name `ConfigureTimeout` and `RpcTimeout` seemed to fit better, but I'm open to suggestions!

I ran most of the tests and they pass, but others would get stuck with "WARN TaskSchedulerImpl: Initial job has not accepted any resources".  I think its just my machine, so I'd though I would push what I have anyway.

Still left to do:
* I only added a couple unit tests so far, there are probably some more cases to test
* Make sure all uses require a `RpcTimeout`
* Right now, both the `ask` and `Await.result` use the same timeout, should we differentiate between these in the TimeoutException message?
* I wrapped `Await.result` in `RpcTimeout`, should we also wrap `Await.ready`?
* Proper scoping of classes and methods

hardmettle, feel free to help out with any of these!

Author: Bryan Cutler <bjcutler@us.ibm.com>
Author: Harsh Gupta <harsh@Harshs-MacBook-Pro.local>
Author: BryanCutler <cutlerb@gmail.com>

Closes #6205 from BryanCutler/configTimeout-6980 and squashes the following commits:

46c8d48 [Bryan Cutler] [SPARK-6980] Changed RpcEnvSuite test to never reply instead of just sleeping, to avoid possible sync issues
06afa53 [Bryan Cutler] [SPARK-6980] RpcTimeout class extends Serializable, was causing error in MasterSuite
7bb70f1 [Bryan Cutler] Merge branch 'master' into configTimeout-6980
dbd5f73 [Bryan Cutler] [SPARK-6980] Changed RpcUtils askRpcTimeout and lookupRpcTimeout scope to private[spark] and improved deprecation warning msg
4e89c75 [Bryan Cutler] [SPARK-6980] Missed one usage of deprecated RpcUtils.askTimeout in YarnSchedulerBackend although it is not being used, and fixed SparkConfSuite UT to not use deprecated RpcUtils functions
6a1c50d [Bryan Cutler] [SPARK-6980] Minor cleanup of test case
7f4d78e [Bryan Cutler] [SPARK-6980] Fixed scala style checks
287059a [Bryan Cutler] [SPARK-6980] Removed extra import in AkkaRpcEnvSuite
3d8b1ff [Bryan Cutler] [SPARK-6980] Cleaned up imports in AkkaRpcEnvSuite
3a168c7 [Bryan Cutler] [SPARK-6980] Rewrote Akka RpcTimeout UTs in RpcEnvSuite
7636189 [Bryan Cutler] [SPARK-6980] Fixed call to askWithReply in DAGScheduler to use RpcTimeout - this was being compiled by auto-tupling and changing the message type of BlockManagerHeartbeat
be11c4e [Bryan Cutler] Merge branch 'master' into configTimeout-6980
039afed [Bryan Cutler] [SPARK-6980] Corrected import organization
218aa50 [Bryan Cutler] [SPARK-6980] Corrected issues from feedback
fadaf6f [Bryan Cutler] [SPARK-6980] Put back in deprecated RpcUtils askTimeout and lookupTimout to fix MiMa errors
fa6ed82 [Bryan Cutler] [SPARK-6980] Had to increase timeout on positive test case because a processor slowdown could trigger an Future TimeoutException
b05d449 [Bryan Cutler] [SPARK-6980] Changed constructor to use val duration instead of getter function, changed name of string property from conf to timeoutProp for consistency
c6cfd33 [Bryan Cutler] [SPARK-6980] Changed UT ask message timeout to explicitly intercept a SparkException
1394de6 [Bryan Cutler] [SPARK-6980] Moved MessagePrefix to createRpcTimeoutException directly
1517721 [Bryan Cutler] [SPARK-6980] RpcTimeout object scope should be private[spark]
2206b4d [Bryan Cutler] [SPARK-6980] Added unit test for ask then immediat awaitReply
1b9beab [Bryan Cutler] [SPARK-6980] Cleaned up import ordering
08f5afc [Bryan Cutler] [SPARK-6980] Added UT for constructing RpcTimeout with default value
d3754d1 [Bryan Cutler] [SPARK-6980] Added akkaConf to prevent dead letter logging
995d196 [Bryan Cutler] [SPARK-6980] Cleaned up import ordering, comments, spacing from PR feedback
7774d56 [Bryan Cutler] [SPARK-6980] Cleaned up UT imports
4351c48 [Bryan Cutler] [SPARK-6980] Added UT for addMessageIfTimeout, cleaned up UTs
1607a5f [Bryan Cutler] [SPARK-6980] Changed addMessageIfTimeout to PartialFunction, cleanup from PR comments
2f94095 [Bryan Cutler] [SPARK-6980] Added addMessageIfTimeout for when a Future is completed with TimeoutException
235919b [Bryan Cutler] [SPARK-6980] Resolved conflicts after master merge
c07d05c [Bryan Cutler] Merge branch 'master' into configTimeout-6980-tmp
b7fb99f [BryanCutler] Merge pull request #2 from hardmettle/configTimeoutUpdates_6980
4be3a8d [Harsh Gupta] Modifying loop condition to find property match
0ee5642 [Harsh Gupta] Changing the loop condition to halt at the first match in the property list for RpcEnv exception catch
f74064d [Harsh Gupta] Retrieving properties from property list using iterator and while loop instead of chained functions
a294569 [Bryan Cutler] [SPARK-6980] Added creation of RpcTimeout with Seq of property keys
23d2f26 [Bryan Cutler] [SPARK-6980] Fixed await result not being handled by RpcTimeout
49f9f04 [Bryan Cutler] [SPARK-6980] Minor cleanup and scala style fix
5b59a44 [Bryan Cutler] [SPARK-6980] Added some RpcTimeout unit tests
78a2c0a [Bryan Cutler] [SPARK-6980] Using RpcTimeout.awaitResult for future in AppClient now
97523e0 [Bryan Cutler] [SPARK-6980] Akka ask timeout description refactored to RPC layer

This fixes code generation for queries containing `ORDER BY NULL`.  Previously, the generated code would fail to compile.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #7179 from JoshRosen/generate-order-fixes and squashes the following commits:

6ef49a6 [Josh Rosen] Fix ORDER BY NULL
0036696 [Josh Rosen] Add regression test for SPARK-8782 (ORDER BY NULL)

This reverts commit fc7aebd9.

Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>

Closes #6821 from yu-iskw/SPARK-7104 and squashes the following commits:

975136b [Yu ISHIKAWA] Organize import
0ef58b6 [Yu ISHIKAWA] Use rmtree, instead of removedirs
cb21653 [Yu ISHIKAWA] Add an explicit type for `Word2VecModelWrapper.save`
1d468ef [Yu ISHIKAWA] [SPARK-7104][MLlib] Support model save/load in Python's Word2Vec

Also improve the performance of hex/unhex

Author: Davies Liu <davies@databricks.com>

Closes #7181 from davies/hex and squashes the following commits:

f032fbb [Davies Liu] Merge branch 'hex' of github.com:davies/spark into hex
49e325f [Davies Liu] Merge branch 'master' of github.com:apache/spark into hex
b31fc9a [Davies Liu] Update math.scala
25156b7 [Davies Liu] address comments and fix test
c3af78c [Davies Liu] address commments
1a24082 [Davies Liu] Add Python API for hex and unhex

GrandientDescent can receive convergence tolerance value. Default value is 0.0.
When loss value becomes less than the tolerance which is set by user, iteration is terminated.

Author: lewuathe <lewuathe@me.com>

Closes #3636 from Lewuathe/gd-convergence-tolerance and squashes the following commits:

0b8a9a8 [lewuathe] Update doc
ce91b15 [lewuathe] Merge branch 'master' into gd-convergence-tolerance
4f22c2b [lewuathe] Modify based on SPARK-1503
5e47b82 [lewuathe] Merge branch 'master' into gd-convergence-tolerance
abadb7e [lewuathe] Fix LassoSuite
8fadebd [lewuathe] Fix failed unit tests
ee5de46 [lewuathe] Merge branch 'master' into gd-convergence-tolerance
8313ba2 [lewuathe] Fix styles
0ead94c [lewuathe] Merge branch 'master' into gd-convergence-tolerance
a94cfd5 [lewuathe] Modify some styles
3aef0a2 [lewuathe] Modify converged logic to do relative comparison
f7b19d5 [lewuathe] [SPARK-3382] Clarify comparison logic
e6c9cd2 [lewuathe] [SPARK-3382] Compare with the diff of solution vector
4b125d2 [lewuathe] [SPARK3382] Fix scala style
e7c10dd [lewuathe] [SPARK-3382] format improvements
f867eea [lewuathe] [SPARK-3382] Modify warning message statements
b9d5e61 [lewuathe] [SPARK-3382] should compare diff inside loss history and convergence tolerance
5433f71 [lewuathe] [SPARK-3382] GradientDescent convergence tolerance

Author: Reynold Xin <rxin@databricks.com>

Closes #7175 from rxin/implicitCast and squashes the following commits:

88080a2 [Reynold Xin] Clearer definition of implicit type cast.
f0ff97f [Reynold Xin] Added missing file.
c65e532 [Reynold Xin] [SPARK-8772][SQL] Implement implicit type cast for expressions that defines input types.

The existing test suite has a lot of duplicate code and doesn't even cover the most fundamental feature of the HeartbeatReceiver, which is expiring hosts that have not responded in a while.

This introduces manual clocks in `HeartbeatReceiver` and makes it respond to heartbeats only for registered executors. A few internal messages are moved to `receiveAndReply` to increase determinism of the tests so we don't have to rely on flaky constructs like `eventually`.

Author: Andrew Or <andrew@databricks.com>

Closes #7173 from andrewor14/heartbeat-receiver-tests and squashes the following commits:

4a903d6 [Andrew Or] Increase HeartReceiverSuite coverage and clean up

Modified copy_api_dirs.rb and created api-javadocs.js and api-javadocs.css files in order to add badges to javadoc files for :: Experimental ::, :: DeveloperApi ::, and :: AlphaComponent :: tags

Author: Deron Eriksson <deron@us.ibm.com>

Closes #7169 from deroneriksson/SPARK-1564_JavaDocs_badges and squashes the following commits:

a8353db [Deron Eriksson] added license headers to api-docs.css and api-javadocs.css
07feb07 [Deron Eriksson] added linebreaks to make jquery more readable when adding html badge tags
65b4930 [Deron Eriksson] Modified copy_api_dirs.rb and created api-javadocs.js and api-javadocs.css files in order to add badges to javadoc files for :: Experimental ::, :: DeveloperApi ::, and :: AlphaComponent :: tags

The issue is summarized in the JIRA and is caused by this commit: 984ad601.

This patch reverts that commit and fixes the maven build in a different way. We limit the dependencies of `KinesisReceiverSuite` to avoid having to deal with the complexities in how maven deals with transitive test dependencies.

Author: Andrew Or <andrew@databricks.com>

Closes #7193 from andrewor14/fix-kinesis-pom and squashes the following commits:

ca3d5d4 [Andrew Or] Limit kinesis test dependencies
f24e09c [Andrew Or] Revert "[BUILD] Fix Maven build for Kinesis"

Matrices allow zeros to be stored in values. Sometimes a method is handy to check if the numNonZeros are same as number of Active values.

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #6904 from MechCoder/nnz_matrix and squashes the following commits:

252c6b7 [MechCoder] Add to MiMa excludes
e2390f5 [MechCoder] Use count instead of foreach
2f62b2f [MechCoder] Add to MiMa excludes
d6e96ef [MechCoder] [SPARK-8479] Add numNonzeros and numActives to linalg.Matrices

This patch rewrites the old checkpointing code in a way that is easier to understand. It also adds a guard against an invalid specification of checkpoint directory to provide a clearer error message. Most of the changes here are relatively minor.

Author: Andrew Or <andrew@databricks.com>

Closes #6968 from andrewor14/checkpoint-cleanup and squashes the following commits:

4ef8263 [Andrew Or] Use global synchronized instead
6f6fd84 [Andrew Or] Merge branch 'master' of github.com:apache/spark into checkpoint-cleanup
b1437ad [Andrew Or] Warn instead of throw
5484293 [Andrew Or] Merge branch 'master' of github.com:apache/spark into checkpoint-cleanup
7fb4af5 [Andrew Or] Guard against bad settings of checkpoint directory
691da98 [Andrew Or] Simplify checkpoint code / code style / comments

JIRA: https://issues.apache.org/jira/browse/SPARK-8708

Previously the partitions of ratings are only based on the given products. So if the `usersProducts` given for prediction contains only few products or even one product, the generated ratings will be pushed into few or single partition and can't use high parallelism.

The following codes are the example reported in the JIRA. Because it asks the predictions for users on product 2. There is only one partition in the result.

    >>> r1 = (1, 1, 1.0)
    >>> r2 = (1, 2, 2.0)
    >>> r3 = (2, 1, 2.0)
    >>> r4 = (2, 2, 2.0)
    >>> r5 = (3, 1, 1.0)
    >>> ratings = sc.parallelize([r1, r2, r3, r4, r5], 5)
    >>> users = ratings.map(itemgetter(0)).distinct()
    >>> model = ALS.trainImplicit(ratings, 1, seed=10)
    >>> predictions_for_2 = model.predictAll(users.map(lambda u: (u, 2)))
    >>> predictions_for_2.glom().map(len).collect()
    [0, 0, 3, 0, 0]

This PR uses user and product instead of only product to partition the ratings.

Author: Liang-Chi Hsieh <viirya@gmail.com>
Author: Liang-Chi Hsieh <viirya@appier.com>

Closes #7121 from viirya/mfm_fix_partition and squashes the following commits:

779946d [Liang-Chi Hsieh] Calculate approximate numbers of users and products in one pass.
4336dc2 [Liang-Chi Hsieh] Merge remote-tracking branch 'upstream/master' into mfm_fix_partition
83e56c1 [Liang-Chi Hsieh] Instead of additional join, use the numbers of users and products to decide how to perform join.
b534dc8 [Liang-Chi Hsieh] Paritition ratings based on both users and products.

This is a follow up of [SPARK-8283](https://issues.apache.org/jira/browse/SPARK-8283) ([PR-6828](https://github.com/apache/spark/pull/6828)), to support both `struct` and `named_struct` in Spark SQL.

After [#6725](https://github.com/apache/spark/pull/6828), the semantic of [`CreateStruct`](https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypes.scala#L56) methods have changed a little and do not limited to cols of `NamedExpressions`, it will name non-NamedExpression fields following the hive convention, col1, col2 ...

This PR would both loosen [`struct`](https://github.com/apache/spark/blob/master/sql/core/src/main/scala/org/apache/spark/sql/functions.scala#L723) to take children of `Expression` type and add `named_struct` support.

Author: Yijie Shen <henry.yijieshen@gmail.com>

Closes #6874 from yijieshen/SPARK-8283 and squashes the following commits:

4cd3375ac [Yijie Shen] change struct documentation
d599d0b [Yijie Shen] rebase code
9a7039e [Yijie Shen] fix reviews and regenerate golden answers
b487354 [Yijie Shen] replace assert using checkAnswer
f07e114 [Yijie Shen] tiny fix
9613be9 [Yijie Shen] review fix
7fef712 [Yijie Shen] Fix checkInputTypes' implementation using foldable and nullable
60812a7 [Yijie Shen] Fix type check
828d694 [Yijie Shen] remove unnecessary resolved assertion inside dataType method
fd3cd8e [Yijie Shen] remove type check from eval
7a71255 [Yijie Shen] tiny fix
ccbbd86 [Yijie Shen] Fix reviews
47da332 [Yijie Shen] remove nameStruct API from DataFrame
917e680 [Yijie Shen] Fix reviews
4bd75ad [Yijie Shen] loosen struct method in functions.scala to take Expression children
0acb7be [Yijie Shen] Add CreateNamedStruct in both DataFrame function API and FunctionRegistery