Updated programming-guide.md

Made sure that readers know the random number generator seed argument, within the 'takeSample' method, is optional.

Author: Rishi Verma <riverma@apache.org>

Closes #1324 from riverma/patch-1 and squashes the following commits:

4699676 [Rishi Verma] Updated programming-guide.md
Resolve sbt warnings during build Ⅱ

Author: witgo <witgo@qq.com>

Closes #1153 from witgo/expectResult and squashes the following commits:

97541d8 [witgo] merge master
ead26e7 [witgo] Resolve sbt warnings during build
[SPARK-2391][SQL] Custom take() for LIMIT queries.

Using Spark's take can result in an entire in-memory partition to be shipped in order to retrieve a single row.

Author: Michael Armbrust <michael@databricks.com>

Closes #1318 from marmbrus/takeLimit and squashes the following commits:

77289a5 [Michael Armbrust] Update scala doc
32f0674 [Michael Armbrust] Custom take implementation for LIMIT queries.
[EC2] Add default history server port to ec2 script

Right now I have to open it manually

Author: Andrew Or <andrewor14@gmail.com>

Closes #1296 from andrewor14/hist-serv-port and squashes the following commits:

8895a1f [Andrew Or] Add default history server port to ec2 script
[SPARK-2395][SQL] Optimize common LIKE patterns.

Author: Michael Armbrust <michael@databricks.com>

Closes #1325 from marmbrus/slowLike and squashes the following commits:

023c3eb [Michael Armbrust] add comment.
8b421c2 [Michael Armbrust] Handle the case where the final % is actually escaped.
d34d37e [Michael Armbrust] add periods.
3bbf35f [Michael Armbrust] Roll back changes to SparkBuild
53894b1 [Michael Armbrust] Fix grammar.
4094462 [Michael Armbrust] Fix grammar.
6d3d0a0 [Michael Armbrust] Optimize common LIKE patterns.
[SPARK-2403] Catch all errors during serialization in DAGScheduler

https://issues.apache.org/jira/browse/SPARK-2403

Spark hangs for us whenever we forget to register a class with Kryo. This should be a simple fix for that. But let me know if you have a better suggestion.

I did not write a new test for this. It would be pretty complicated and I'm not sure it's worthwhile for such a simple change. Let me know if you disagree.

Author: Daniel Darabos <darabos.daniel@gmail.com>

Closes #1329 from darabos/spark-2403 and squashes the following commits:

3aceaad [Daniel Darabos] Print full stack trace for miscellaneous exceptions during serialization.
52c22ba [Daniel Darabos] Only catch NonFatal exceptions.
361e962 [Daniel Darabos] Catch all errors during serialization in DAGScheduler.
SPARK-2400 : fix spark.yarn.max.executor.failures explaination

According to
```scala
  private val maxNumExecutorFailures = sparkConf.getInt("spark.yarn.max.executor.failures",
    sparkConf.getInt("spark.yarn.max.worker.failures", math.max(args.numExecutors * 2, 3)))
```
default value should be numExecutors * 2, with minimum of 3,  and it's same to the config
`spark.yarn.max.worker.failures`

Author: CrazyJvm <crazyjvm@gmail.com>

Closes #1282 from CrazyJvm/yarn-doc and squashes the following commits:

1a5f25b [CrazyJvm] remove deprecated config
c438aec [CrazyJvm] fix style
86effa6 [CrazyJvm] change expression
211f130 [CrazyJvm] fix html tag
2900d23 [CrazyJvm] fix style
a4b2e27 [CrazyJvm] fix configuration spark.yarn.max.executor.failures
[SPARK-2409] Make SQLConf thread safe.

Author: Reynold Xin <rxin@apache.org>

Closes #1334 from rxin/sqlConfThreadSafetuy and squashes the following commits:

c1e0a5a [Reynold Xin] Fixed the duplicate comment.
7614372 [Reynold Xin] [SPARK-2409] Make SQLConf thread safe.
[SPARK-2362] Fix for newFilesOnly logic in file DStream

The newFilesOnly logic should be inverted: the logic should be that if the flag newFilesOnly==true then only start reading files older than current time. As the code is now if newFilesOnly==true then it will start to read files that are older than 0L (that is: every file in the directory).

Author: Gabriele Nizzoli <mail@nizzoli.net>

Closes #1077 from gabrielenizzoli/master and squashes the following commits:

4f1d261 [Gabriele Nizzoli] Fix for newFilesOnly logic in file DStream
[SPARK-2392] Executors should not start their own HTTP servers

Executors currently start their own unused HTTP file servers. This is because we use the same SparkEnv class for both executors and drivers, and we do not distinguish this case.

In the longer term, we should separate out SparkEnv for the driver and SparkEnv for the executors.

Author: Andrew Or <andrewor14@gmail.com>

Closes #1335 from andrewor14/executor-http-server and squashes the following commits:

46ef263 [Andrew Or] Start HTTP server only on the driver
[SPARK-2413] Upgrade junit_xml_listener to 0.5.1

which fixes the following issues

1) fix the class name to be fully qualified classpath
2) make sure the the reporting time is in second not in miliseond, which causing JUnit HTML to report incorrect number
3) make sure the duration of the tests are accumulative.

Author: DB Tsai <dbtsai@alpinenow.com>

Closes #1333 from dbtsai/dbtsai-junit and squashes the following commits:

bbeac4b [DB Tsai] Upgrade junit_xml_listener to 0.5.1 which fixes the following issues
[SPARK-2152][MLlib] fix bin offset in DecisionTree node aggregations (also resolves SPARK-2160)

Hi, this pull fixes (what I believe to be) a bug in DecisionTree.scala.

In the extractLeftRightNodeAggregates function, the first set of rightNodeAgg values for Regression are set in line 792 as follows:

rightNodeAgg(featureIndex)(2 * (numBins - 2))
  = binData(shift + (2 * numBins - 1)))

Then there is a loop that sets the rest of the values, as in line 809:

rightNodeAgg(featureIndex)(2 * (numBins - 2 - splitIndex)) =
  binData(shift + (2 *(numBins - 2 - splitIndex))) +
  rightNodeAgg(featureIndex)(2 * (numBins - 1 - splitIndex))

But since splitIndex starts at 1, this ends up skipping a set of binData values.

The changes here address this issue, for both the Regression and Classification cases.

Author: johnnywalleye <jsondag@gmail.com>

Closes #1316 from johnnywalleye/master and squashes the following commits:

73809da [johnnywalleye] fix bin offset in DecisionTree node aggregations
[SPARK-2384] Add tooltips to UI.

This patch adds tooltips to clarify some points of confusion in the UI.  When users mouse over some of the table headers (shuffle read, write, and input size) as well as over the "scheduler delay" metric shown for each stage, a black tool tip (see image below) pops up describing the metric in more detail.  After the tooltip mechanism is added by this commit, I imagine others may want to add more tooltips for other things in the UI, but I think this is a good starting point.

![tooltip](https://cloud.githubusercontent.com/assets/1108612/3491905/994e179e-059f-11e4-92f2-c6c12d248d81.jpg)

This looks scary-big but much of it is adding the bootstrap tool tip JavaScript.

Also I have no idea what to put for the license in tooltip (I left it the same -- the Twitter apache header) or for JQuery (left it as nothing) -- @mateiz what's the right thing here?

cc @pwendell @andrewor14 @rxin

Author: Kay Ousterhout <kayousterhout@gmail.com>

Closes #1314 from kayousterhout/tooltips and squashes the following commits:

19981b5 [Kay Ousterhout] Exclude non-licensed javascript files from style check
d9ab5a9 [Kay Ousterhout] Response to Andrew's review
7752449 [Kay Ousterhout] [SPARK-2384] Add tooltips to UI.
[STREAMING] SPARK-2343: Fix QueueInputDStream with oneAtATime false

Fix QueueInputDStream which was not removing dequeued items when used with the oneAtATime flag disabled.

Author: Manuel Laflamme <manuel.laflamme@gmail.com>

Closes #1285 from mlaflamm/spark-2343 and squashes the following commits:

61c9e38 [Manuel Laflamme] Unit tests for queue input stream
c51d029 [Manuel Laflamme] Fix QueueInputDStream with oneAtATime false
[SPARK-2417][MLlib] Fix DecisionTree tests

Fixes test failures introduced by https://github.com/apache/spark/pull/1316.

For both the regression and classification cases,
val stats is the InformationGainStats for the best tree split.
stats.predict is the predicted value for the data, before the split is made.
Since 600 of the 1,000 values generated by DecisionTreeSuite.generateCategoricalDataPoints() are 1.0 and the rest 0.0, the regression tree and classification tree both correctly predict a value of 0.6 for this data now, and the assertions have been changed to reflect that.

Author: johnnywalleye <jsondag@gmail.com>

Closes #1343 from johnnywalleye/decision-tree-tests and squashes the following commits:

ef80603 [johnnywalleye] [SPARK-2417][MLlib] Fix DecisionTree tests
SPARK-1782: svd for sparse matrix using ARPACK

copy ARPACK dsaupd/dseupd code from latest breeze
change RowMatrix to use sparse SVD
change tests for sparse SVD

All tests passed. I will run it against some large matrices.

Author: Li Pu <lpu@twitter.com>
Author: Xiangrui Meng <meng@databricks.com>
Author: Li Pu <li.pu@outlook.com>

Closes #964 from vrilleup/master and squashes the following commits:

7312ec1 [Li Pu] very minor comment fix
4c618e9 [Li Pu] Merge pull request #1 from mengxr/vrilleup-master
a461082 [Xiangrui Meng] make superscript show up correctly in doc
861ec48 [Xiangrui Meng] simplify axpy
62969fa [Xiangrui Meng] use BDV directly in symmetricEigs change the computation mode to local-svd, local-eigs, and dist-eigs update tests and docs
c273771 [Li Pu] automatically determine SVD compute mode and parameters
7148426 [Li Pu] improve RowMatrix multiply
5543cce [Li Pu] improve svd api
819824b [Li Pu] add flag for dense svd or sparse svd
eb15100 [Li Pu] fix binary compatibility
4c7aec3 [Li Pu] improve comments
e7850ed [Li Pu] use aggregate and axpy
827411b [Li Pu] fix EOF new line
9c80515 [Li Pu] use non-sparse implementation when k = n
fe983b0 [Li Pu] improve scala style
96d2ecb [Li Pu] improve eigenvalue sorting
e1db950 [Li Pu] SPARK-1782: svd for sparse matrix using ARPACK
Move ShuffleBlockmanager behind shuffleManager
Fix test cases
Fix getBlockLocation
Fix code style