[SPARK-1484][MLLIB] Warn when running an iterative algorithm on uncached data.

Add warnings to KMeans, GeneralizedLinearAlgorithm, and computeSVD when called with input data that is not cached. KMeans is implemented iteratively, and I believe that GeneralizedLinearAlgorithm’s current optimizers are iterative and its future optimizers are also likely to be iterative. RowMatrix’s computeSVD is iterative against an RDD when run in DistARPACK mode. ALS and DecisionTree are iterative as well, but they implement RDD caching internally so do not require a warning.

I added a warning to GeneralizedLinearAlgorithm rather than inside its optimizers, where the iteration actually occurs, because internally GeneralizedLinearAlgorithm maps its input data to an uncached RDD before passing it to an optimizer. (In other words, the warning would be printed for every GeneralizedLinearAlgorithm run, regardless of whether its input is cached, if the warning were in GradientDescent or other optimizer.) I assume that use of an uncached RDD by GeneralizedLinearAlgorithm is intentional, and that the mapping there (adding label, intercepts and scaling) is a lightweight operation. Arguably a user calling an optimizer such as GradientDescent will be knowledgable enough to cache their data without needing a log warning, so lack of a warning in the optimizers may be ok.

Some of the documentation examples making use of these iterative algorithms did not cache their training RDDs (while others did). I updated the examples to always cache. I also fixed some (unrelated) minor errors in the documentation examples.

Author: Aaron Staple <aaron.staple@gmail.com>

Closes #2347 from staple/SPARK-1484 and squashes the following commits:

bd49701 [Aaron Staple] Address review comments.
ab2d4a4 [Aaron Staple] Disable warnings on python code path.
a7a0f99 [Aaron Staple] Change code comments per review comments.
7cca1dc [Aaron Staple] Change warning message text.
c77e939 [Aaron Staple] [SPARK-1484][MLLIB] Warn when running an iterative algorithm on uncached data.
3b6c511 [Aaron Staple] Minor doc example fixes.
[SPARK-3584] sbin/slaves doesn't work when we use password authentication for SSH

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #2444 from sarutak/slaves-scripts-modification and squashes the following commits:

eff7394 [Kousuke Saruta] Improve the description about Cluster Launch Script in docs/spark-standalone.md
7858225 [Kousuke Saruta] Modified sbin/slaves to use the environment variable "SPARK_SSH_FOREGROUND" as a flag
53d7121 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into slaves-scripts-modification
e570431 [Kousuke Saruta] Added a description for SPARK_SSH_FOREGROUND variable
7120a0c [Kousuke Saruta] Added a description about default host for sbin/slaves
1bba8a9 [Kousuke Saruta] Added SPARK_SSH_FOREGROUND flag to sbin/slaves
88e2f17 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into slaves-scripts-modification
297e75d [Kousuke Saruta] Modified sbin/slaves not to export HOSTLIST
SPARK-2634: Change MapOutputTrackerWorker.mapStatuses to ConcurrentHashMap

MapOutputTrackerWorker.mapStatuses is used concurrently, it should be thread-safe. This bug has already been fixed in #1328. Nevertheless, considering #1328 won't be merged soon, I send this trivial fix and hope this issue can be solved soon.

Author: zsxwing <zsxwing@gmail.com>

Closes #1541 from zsxwing/SPARK-2634 and squashes the following commits:

d450053 [zsxwing] SPARK-2634: Change MapOutputTrackerWorker.mapStatuses to ConcurrentHashMap
[SPARK-3686][STREAMING] Wait for sink to commit the channel before check...

...ing for the channel size.

Author: Hari Shreedharan <hshreedharan@apache.org>

Closes #2531 from harishreedharan/sparksinksuite-fix and squashes the following commits:

30393c1 [Hari Shreedharan] Use more deterministic method to figure out when batches come in.
6ce9d8b [Hari Shreedharan] [SPARK-3686][STREAMING] Wait for sink to commit the channel before checking for the channel size.
[SPARK-3478] [PySpark] Profile the Python tasks

This patch add profiling support for PySpark, it will show the profiling results
before the driver exits, here is one example:

```
============================================================
Profile of RDD<id=3>
============================================================
         5146507 function calls (5146487 primitive calls) in 71.094 seconds

   Ordered by: internal time, cumulative time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
  5144576   68.331    0.000   68.331    0.000 statcounter.py:44(merge)
       20    2.735    0.137   71.071    3.554 statcounter.py:33(__init__)
       20    0.017    0.001    0.017    0.001 {cPickle.dumps}
     1024    0.003    0.000    0.003    0.000 t.py:16(<lambda>)
       20    0.001    0.000    0.001    0.000 {reduce}
       21    0.001    0.000    0.001    0.000 {cPickle.loads}
       20    0.001    0.000    0.001    0.000 copy_reg.py:95(_slotnames)
       41    0.001    0.000    0.001    0.000 serializers.py:461(read_int)
       40    0.001    0.000    0.002    0.000 serializers.py:179(_batched)
       62    0.000    0.000    0.000    0.000 {method 'read' of 'file' objects}
       20    0.000    0.000   71.072    3.554 rdd.py:863(<lambda>)
       20    0.000    0.000    0.001    0.000 serializers.py:198(load_stream)
    40/20    0.000    0.000   71.072    3.554 rdd.py:2093(pipeline_func)
       41    0.000    0.000    0.002    0.000 serializers.py:130(load_stream)
       40    0.000    0.000   71.072    1.777 rdd.py:304(func)
       20    0.000    0.000   71.094    3.555 worker.py:82(process)
```

Also, use can show profile result manually by `sc.show_profiles()` or dump it into disk
by `sc.dump_profiles(path)`, such as

```python
>>> sc._conf.set("spark.python.profile", "true")
>>> rdd = sc.parallelize(range(100)).map(str)
>>> rdd.count()
100
>>> sc.show_profiles()
============================================================
Profile of RDD<id=1>
============================================================
         284 function calls (276 primitive calls) in 0.001 seconds

   Ordered by: internal time, cumulative time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        4    0.000    0.000    0.000    0.000 serializers.py:198(load_stream)
        4    0.000    0.000    0.000    0.000 {reduce}
     12/4    0.000    0.000    0.001    0.000 rdd.py:2092(pipeline_func)
        4    0.000    0.000    0.000    0.000 {cPickle.loads}
        4    0.000    0.000    0.000    0.000 {cPickle.dumps}
      104    0.000    0.000    0.000    0.000 rdd.py:852(<genexpr>)
        8    0.000    0.000    0.000    0.000 serializers.py:461(read_int)
       12    0.000    0.000    0.000    0.000 rdd.py:303(func)
```
The profiling is disabled by default, can be enabled by "spark.python.profile=true".

Also, users can dump the results into disks automatically for future analysis, by "spark.python.profile.dump=path_to_dump"

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

Closes #2351 from davies/profiler and squashes the following commits:

7ef2aa0 [Davies Liu] bugfix, add tests for show_profiles and dump_profiles()
2b0daf2 [Davies Liu] fix docs
7a56c24 [Davies Liu] bugfix
cba9463 [Davies Liu] move show_profiles and dump_profiles to SparkContext
fb9565b [Davies Liu] Merge branch 'master' of github.com:apache/spark into profiler
116d52a [Davies Liu] Merge branch 'master' of github.com:apache/spark into profiler
09d02c3 [Davies Liu] Merge branch 'master' into profiler
c23865c [Davies Liu] Merge branch 'master' into profiler
15d6f18 [Davies Liu] add docs for two configs
dadee1a [Davies Liu] add docs string and clear profiles after show or dump
4f8309d [Davies Liu] address comment, add tests
0a5b6eb [Davies Liu] fix Python UDF
4b20494 [Davies Liu] add profile for python
SPARK-3639 | Removed settings master in examples

This patch removes setting of master as local in Kinesis examples so that users can set it using submit-job.

Author: aniketbhatnagar <aniket.bhatnagar@gmail.com>

Closes #2536 from aniketbhatnagar/Kinesis-Examples-Master-Unset and squashes the following commits:

c9723ac [aniketbhatnagar] Merge remote-tracking branch 'origin/Kinesis-Examples-Master-Unset' into Kinesis-Examples-Master-Unset
fec8ead [aniketbhatnagar] SPARK-3639 | Removed settings master in examples
31cdc59 [aniketbhatnagar] SPARK-3639 | Removed settings master in examples
[SPARK-3614][MLLIB] Add minimumOccurence filtering to IDF

This PR for [SPARK-3614](https://issues.apache.org/jira/browse/SPARK-3614) adds functionality for filtering out terms which do not appear in at least a minimum number of documents.

This is implemented using a minimumOccurence parameter (default 0).  When terms' document frequencies are less than minimumOccurence, their IDFs are set to 0, just like when the DF is 0.  As a result, the TF-IDFs for the terms are found to be 0, as if the terms were not present in the documents.

This PR makes the following changes:
* Add a minimumOccurence parameter to the IDF and DocumentFrequencyAggregator classes.
* Create a parameter-less constructor for IDF with a default minimumOccurence value of 0 to remain backwards-compatibility with the original IDF API.
* Sets the IDFs to 0 for terms which DFs are less than minimumOccurence
* Add tests to the Spark IDFSuite and Java JavaTfIdfSuite test suites
* Updated the MLLib Feature Extraction programming guide to describe the new feature

Author: RJ Nowling <rnowling@gmail.com>

Closes #2494 from rnowling/spark-3614-idf-filter and squashes the following commits:

0aa3c63 [RJ Nowling] Fix identation
e6523a8 [RJ Nowling] Remove unnecessary toDouble's from IDFSuite
bfa82ec [RJ Nowling] Add space after if
30d20b3 [RJ Nowling] Add spaces around equals signs
9013447 [RJ Nowling] Add space before division operator
79978fc [RJ Nowling] Remove unnecessary semi-colon
40fd70c [RJ Nowling] Change minimumOccurence to minDocFreq in code and docs
47850ab [RJ Nowling] Changed minimumOccurence to Int from Long
9fb4093 [RJ Nowling] Remove unnecessary lines from IDF class docs
1fc09d8 [RJ Nowling] Add backwards-compatible constructor to DocumentFrequencyAggregator
1801fd2 [RJ Nowling] Fix style errors in IDF.scala
6897252 [RJ Nowling] Preface minimumOccurence members with val to make them final and immutable
a200bab [RJ Nowling] Remove unnecessary else statement
4b974f5 [RJ Nowling] Remove accidentally-added import from testing
c0cc643 [RJ Nowling] Add minimumOccurence filtering to IDF
[SPARK-3695]shuffle fetch fail output

should output detailed host and port in error message

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

Closes #2539 from adrian-wang/fetchfail and squashes the following commits:

6c1b1e0 [Daoyuan Wang] shuffle fetch fail output
[SPARK-3476] Remove outdated memory checks in Yarn

See description in [JIRA](https://issues.apache.org/jira/browse/SPARK-3476).

Author: Andrew Or <andrewor14@gmail.com>

Closes #2528 from andrewor14/yarn-memory-checks and squashes the following commits:

c5400cd [Andrew Or] Simplify checks
e30ffac [Andrew Or] Remove outdated memory checks
[SPARK-3531][SQL]select null from table would throw a MatchError

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

Closes #2396 from adrian-wang/selectnull and squashes the following commits:

2458229 [Daoyuan Wang] rebase solution
[SPARK-3393] [SQL] Align the log4j configuration for Spark & SparkSQLCLI

User may be confused for the HQL logging & configurations, we'd better provide a default templates.

Both files are copied from Hive.

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

Closes #2263 from chenghao-intel/hive_template and squashes the following commits:

53bffa9 [Cheng Hao] Remove the hive-log4j.properties initialization
Revert "[SPARK-3478] [PySpark] Profile the Python tasks"

This reverts commit 1aa549ba9839565274a12c52fa1075b424f138a6.
[SPARK-3543] Write TaskContext in Java and expose it through a static accessor.

Author: Prashant Sharma <prashant.s@imaginea.com>
Author: Shashank Sharma <shashank21j@gmail.com>

Closes #2425 from ScrapCodes/SPARK-3543/withTaskContext and squashes the following commits:

8ae414c [Shashank Sharma] CR
ee8bd00 [Prashant Sharma] Added internal API in docs comments.
ddb8cbe [Prashant Sharma] Moved setting the thread local to where TaskContext is instantiated.
a7d5e23 [Prashant Sharma] Added doc comments.
edf945e [Prashant Sharma] Code review git add -A
f716fd1 [Prashant Sharma] introduced thread local for getting the task context.
333c7d6 [Prashant Sharma] Translated Task context from scala to java.
Close #2194.
Slaves file is now a template.

Change 0dc868e removed the `conf/slaves` file and made it a template like most of the other configuration files. This means you can no longer run `make-distribution.sh` unless you manually create a slaves file to be statically bundled in your distribution, which seems at odds with making it a template file.

Author: Sarah Gerweck <sarah.a180@gmail.com>

Closes #2549 from sarahgerweck/noMoreSlaves and squashes the following commits:

d11d99a [Sarah Gerweck] Slaves file is now a template.
[Build]remove spark-staging-1030

Since 1.1.0 has published, remove spark-staging-1030.

Author: wangfei <wangfei1@huawei.com>

Closes #2532 from scwf/patch-2 and squashes the following commits:

bc9e00b [wangfei] remove spark-staging-1030
[SQL][DOCS] Clarify that the server is for JDBC and ODBC

Author: Michael Armbrust <michael@databricks.com>

Closes #2527 from marmbrus/patch-1 and squashes the following commits:

a0f9f1c [Michael Armbrust] [SQL][DOCS] Clarify that the server is for JDBC and ODBC
[SPARK-3675][SQL] Allow starting a JDBC server on an existing context

Author: Michael Armbrust <michael@databricks.com>

Closes #2515 from marmbrus/jdbcExistingContext and squashes the following commits:

7866fad [Michael Armbrust] Allows starting a JDBC server on an existing context.
stop, start and destroy require the EC2_REGION

i.e
./spark-ec2 --region=us-west-1 stop yourclustername

Author: Jeff Steinmetz <jeffrey.steinmetz@gmail.com>

Closes #2473 from jeffsteinmetz/master and squashes the following commits:

7491f2c [Jeff Steinmetz] fix case in EC2 cluster setup documentation
bd3d777 [Jeff Steinmetz] standardized ec2 documenation to use <lower-case> sample args
2bf4a57 [Jeff Steinmetz] standardized ec2 documenation to use <lower-case> sample args
68d8372 [Jeff Steinmetz] standardized ec2 documenation to use <lower-case> sample args
d2ab6e2 [Jeff Steinmetz] standardized ec2 documenation to use <lower-case> sample args
520e6dc [Jeff Steinmetz] standardized ec2 documenation to use <lower-case> sample args
37fc876 [Jeff Steinmetz] stop, start and destroy require the EC2_REGION
[SPARK-1021] Defer the data-driven computation of partition bounds in so...

...rtByKey() until evaluation.

Author: Erik Erlandson <eerlands@redhat.com>

Closes #1689 from erikerlandson/spark-1021-pr and squashes the following commits:

50b6da6 [Erik Erlandson] use standard getIteratorSize in countAsync
4e334a9 [Erik Erlandson] exception mystery fixed by fixing bug in ComplexFutureAction
b88b5d4 [Erik Erlandson] tweak async actions to use ComplexFutureAction[T] so they handle RangePartitioner sampling job properly
b2b20e8 [Erik Erlandson] Fix bug in exception passing with ComplexFutureAction[T]
ca8913e [Erik Erlandson] RangePartition sampling job -> FutureAction
7143f97 [Erik Erlandson] [SPARK-1021] modify range bounds variable to be thread safe
ac67195 [Erik Erlandson] [SPARK-1021] Defer the data-driven computation of partition bounds in sortByKey() until evaluation.