[SPARK-2523] [SQL] Hadoop table scan bug fixing

In HiveTableScan.scala, ObjectInspector was created for all of the partition based records, which probably causes ClassCastException if the object inspector is not identical among table & partitions.

This is the follow up with:
https://github.com/apache/spark/pull/1408
https://github.com/apache/spark/pull/1390

I've run a micro benchmark in my local with 15000000 records totally, and got the result as below:

With This Patch  |  Partition-Based Table  |  Non-Partition-Based Table
------------ | ------------- | -------------
No  |  1927 ms  |  1885 ms
Yes  | 1541 ms  |  1524 ms

It showed this patch will also improve the performance.

PS:  the benchmark code is also attached. (thanks liancheng )
```
package org.apache.spark.sql.hive

import org.apache.spark.SparkContext
import org.apache.spark.SparkConf
import org.apache.spark.sql._

object HiveTableScanPrepare extends App {
  case class Record(key: String, value: String)

  val sparkContext = new SparkContext(
    new SparkConf()
      .setMaster("local")
      .setAppName(getClass.getSimpleName.stripSuffix("$")))

  val hiveContext = new LocalHiveContext(sparkContext)

  val rdd = sparkContext.parallelize((1 to 3000000).map(i => Record(s"$i", s"val_$i")))

  import hiveContext._

  hql("SHOW TABLES")
  hql("DROP TABLE if exists part_scan_test")
  hql("DROP TABLE if exists scan_test")
  hql("DROP TABLE if exists records")
  rdd.registerAsTable("records")

  hql("""CREATE TABLE part_scan_test (key STRING, value STRING) PARTITIONED BY (part1 string, part2 STRING)
                 | ROW FORMAT SERDE
                 | 'org.apache.hadoop.hive.serde2.columnar.LazyBinaryColumnarSerDe'
                 | STORED AS RCFILE
               """.stripMargin)
  hql("""CREATE TABLE scan_test (key STRING, value STRING)
                 | ROW FORMAT SERDE
                 | 'org.apache.hadoop.hive.serde2.columnar.LazyBinaryColumnarSerDe'
                 | STORED AS RCFILE
               """.stripMargin)

  for (part1 <- 2000 until 2001) {
    for (part2 <- 1 to 5) {
      hql(s"""from records
                 | insert into table part_scan_test PARTITION (part1='$part1', part2='2010-01-$part2')
                 | select key, value
               """.stripMargin)
      hql(s"""from records
                 | insert into table scan_test select key, value
               """.stripMargin)
    }
  }
}

object HiveTableScanTest extends App {
  val sparkContext = new SparkContext(
    new SparkConf()
      .setMaster("local")
      .setAppName(getClass.getSimpleName.stripSuffix("$")))

  val hiveContext = new LocalHiveContext(sparkContext)

  import hiveContext._

  hql("SHOW TABLES")
  val part_scan_test = hql("select key, value from part_scan_test")
  val scan_test = hql("select key, value from scan_test")

  val r_part_scan_test = (0 to 5).map(i => benchmark(part_scan_test))
  val r_scan_test = (0 to 5).map(i => benchmark(scan_test))
  println("Scanning Partition-Based Table")
  r_part_scan_test.foreach(printResult)
  println("Scanning Non-Partition-Based Table")
  r_scan_test.foreach(printResult)

  def printResult(result: (Long, Long)) {
    println(s"Duration: ${result._1} ms Result: ${result._2}")
  }

  def benchmark(srdd: SchemaRDD) = {
    val begin = System.currentTimeMillis()
    val result = srdd.count()
    val end = System.currentTimeMillis()
    ((end - begin), result)
  }
}
```

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

Closes #1439 from chenghao-intel/hadoop_table_scan and squashes the following commits:

888968f [Cheng Hao] Fix issues in code style
27540ba [Cheng Hao] Fix the TableScan Bug while partition serde differs
40a24a7 [Cheng Hao] Add Unit Test
[SPARK-2479][MLlib] Comparing floating-point numbers using relative error in UnitTests

Floating point math is not exact, and most floating-point numbers end up being slightly imprecise due to rounding errors.

Simple values like 0.1 cannot be precisely represented using binary floating point numbers, and the limited precision of floating point numbers means that slight changes in the order of operations or the precision of intermediates can change the result.

That means that comparing two floats to see if they are equal is usually not what we want. As long as this imprecision stays small, it can usually be ignored.

Based on discussion in the community, we have implemented two different APIs for relative tolerance, and absolute tolerance. It makes sense that test writers should know which one they need depending on their circumstances.

Developers also need to explicitly specify the eps, and there is no default value which will sometimes cause confusion.

When comparing against zero using relative tolerance, a exception will be raised to warn users that it's meaningless.

For relative tolerance, users can now write

    assert(23.1 ~== 23.52 relTol 0.02)
    assert(23.1 ~== 22.74 relTol 0.02)
    assert(23.1 ~= 23.52 relTol 0.02)
    assert(23.1 ~= 22.74 relTol 0.02)
    assert(!(23.1 !~= 23.52 relTol 0.02))
    assert(!(23.1 !~= 22.74 relTol 0.02))

    // This will throw exception with the following message.
    // "Did not expect 23.1 and 23.52 to be within 0.02 using relative tolerance."
    assert(23.1 !~== 23.52 relTol 0.02)

    // "Expected 23.1 and 22.34 to be within 0.02 using relative tolerance."
    assert(23.1 ~== 22.34 relTol 0.02)

For absolute error,

    assert(17.8 ~== 17.99 absTol 0.2)
    assert(17.8 ~== 17.61 absTol 0.2)
    assert(17.8 ~= 17.99 absTol 0.2)
    assert(17.8 ~= 17.61 absTol 0.2)
    assert(!(17.8 !~= 17.99 absTol 0.2))
    assert(!(17.8 !~= 17.61 absTol 0.2))

    // This will throw exception with the following message.
    // "Did not expect 17.8 and 17.99 to be within 0.2 using absolute error."
    assert(17.8 !~== 17.99 absTol 0.2)

    // "Expected 17.8 and 17.59 to be within 0.2 using absolute error."
    assert(17.8 ~== 17.59 absTol 0.2)

Authors:
  DB Tsai <dbtsaialpinenow.com>
  Marek Kolodziej <marekalpinenow.com>

Author: DB Tsai <dbtsai@alpinenow.com>

Closes #1425 from dbtsai/SPARK-2479_comparing_floating_point and squashes the following commits:

8c7cbcc [DB Tsai] Alpine Data Labs
[SPARK-2410][SQL] Merging Hive Thrift/JDBC server (with Maven profile fix)

JIRA issue: [SPARK-2410](https://issues.apache.org/jira/browse/SPARK-2410)

Another try for #1399 & #1600. Those two PR breaks Jenkins builds because we made a separate profile `hive-thriftserver` in sub-project `assembly`, but the `hive-thriftserver` module is defined outside the `hive-thriftserver` profile. Thus every time a pull request that doesn't touch SQL code will also execute test suites defined in `hive-thriftserver`, but tests fail because related .class files are not included in the assembly jar.

In the most recent commit, module `hive-thriftserver` is moved into its own profile to fix this problem. All previous commits are squashed for clarity.

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

Closes #1620 from liancheng/jdbc-with-maven-fix and squashes the following commits:

629988e [Cheng Lian] Moved hive-thriftserver module definition into its own profile
ec3c7a7 [Cheng Lian] Cherry picked the Hive Thrift server
Use commons-lang3 in SignalLogger rather than commons-lang

Spark only transitively depends on the latter, based on the Hadoop version.

Author: Aaron Davidson <aaron@databricks.com>

Closes #1621 from aarondav/lang3 and squashes the following commits:

93c93bf [Aaron Davidson] Use commons-lang3 in SignalLogger rather than commons-lang
Excess judgment

Author: Yadong Qi <qiyadong2010@gmail.com>

Closes #1629 from watermen/bug-fix2 and squashes the following commits:

59b7237 [Yadong Qi] Update HiveQl.scala
[SPARK-2580] [PySpark] keep silent in worker if JVM close the socket

During rdd.take(n), JVM will close the socket if it had got enough data, the Python worker should keep silent in this case.

In the same time, the worker should not print the trackback into stderr if it send the traceback to JVM successfully.

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

Closes #1625 from davies/error and squashes the following commits:

4fbcc6d [Davies Liu] disable log4j during testing when exception is expected.
cc14202 [Davies Liu] keep silent in worker if JVM close the socket
[SPARK-791] [PySpark] fix pickle itemgetter with cloudpickle

fix the problem with pickle operator.itemgetter with multiple index.

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

Closes #1627 from davies/itemgetter and squashes the following commits:

aabd7fa [Davies Liu] fix pickle itemgetter with cloudpickle
[SPARK-2726] and [SPARK-2727] Remove SortOrder and do in-place sort.

The pull request includes two changes:

1. Removes SortOrder introduced by SPARK-2125. The key ordering already includes the SortOrder information since an Ordering can be reverse. This is similar to Java's Comparator interface. Rarely does an API accept both a Comparator as well as a SortOrder.

2. Replaces the sortWith call in HashShuffleReader with an in-place quick sort.

Author: Reynold Xin <rxin@apache.org>

Closes #1631 from rxin/sortOrder and squashes the following commits:

c9d37e1 [Reynold Xin] [SPARK-2726] and [SPARK-2727] Remove SortOrder and do in-place sort.
[SPARK-2174][MLLIB] treeReduce and treeAggregate

In `reduce` and `aggregate`, the driver node spends linear time on the number of partitions. It becomes a bottleneck when there are many partitions and the data from each partition is big.

SPARK-1485 (#506) tracks the progress of implementing AllReduce on Spark. I did several implementations including butterfly, reduce + broadcast, and treeReduce + broadcast. treeReduce + BT broadcast seems to be right way to go for Spark. Using binary tree may introduce some overhead in communication, because the driver still need to coordinate on data shuffling. In my experiments, n -> sqrt(n) -> 1 gives the best performance in general, which is why I set "depth = 2" in MLlib algorithms. But it certainly needs more testing.

I left `treeReduce` and `treeAggregate` public for easy testing. Some numbers from a test on 32-node m3.2xlarge cluster.

code:

~~~
import breeze.linalg._
import org.apache.log4j._

Logger.getRootLogger.setLevel(Level.OFF)

for (n <- Seq(1, 10, 100, 1000, 10000, 100000, 1000000)) {
  val vv = sc.parallelize(0 until 1024, 1024).map(i => DenseVector.zeros[Double](n))
  var start = System.nanoTime(); vv.treeReduce(_ + _, 2); println((System.nanoTime() - start) / 1e9)
  start = System.nanoTime(); vv.reduce(_ + _); println((System.nanoTime() - start) / 1e9)
}
~~~

out:

| n | treeReduce(,2) | reduce |
|---|---------------------|-----------|
| 10 | 0.215538731 | 0.204206899 |
| 100 | 0.278405907 | 0.205732582 |
| 1000 | 0.208972182 | 0.214298272 |
| 10000 | 0.194792071 | 0.349353687 |
| 100000 | 0.347683285 | 6.086671892 |
| 1000000 | 2.589350682 | 66.572906702 |

CC: @pwendell

This is clearly more scalable than the default implementation. My question is whether we should use this implementation in `reduce` and `aggregate` or put them as separate methods. The concern is that users may use `reduce` and `aggregate` as collect, where having multiple stages doesn't reduce the data size. However, in this case, `collect` is more appropriate.

Author: Xiangrui Meng <meng@databricks.com>

Closes #1110 from mengxr/tree and squashes the following commits:

c6cd267 [Xiangrui Meng] make depth default to 2
b04b96a [Xiangrui Meng] address comments
9bcc5d3 [Xiangrui Meng] add depth for readability
7495681 [Xiangrui Meng] fix compile error
142a857 [Xiangrui Meng] merge master
d58a087 [Xiangrui Meng] move treeReduce and treeAggregate to mllib
8a2a59c [Xiangrui Meng] Merge branch 'master' into tree
be6a88a [Xiangrui Meng] use treeAggregate in mllib
0f94490 [Xiangrui Meng] add docs
eb71c33 [Xiangrui Meng] add treeReduce
fe42a5e [Xiangrui Meng] add treeAggregate
Minor indentation and comment typo fixes.

Author: Aaron Staple <astaple@gmail.com>

Closes #1630 from staple/minor and squashes the following commits:

6f295a2 [Aaron Staple] Fix typos in comment about ExprId.
8566467 [Aaron Staple] Fix off by one column indentation in SqlParser.