This replaces https://github.com/apache/spark/pull/9696

Invoke Checkstyle and print any errors to the console, failing the step.
Use Google's style rules modified according to
https://cwiki.apache.org/confluence/display/SPARK/Spark+Code+Style+Guide
Some important checks are disabled (see TODOs in `checkstyle.xml`) due to
multiple violations being present in the codebase.

Suggest fixing those TODOs in a separate PR(s).

More on Checkstyle can be found on the [official website](http://checkstyle.sourceforge.net/).

Sample output (from [build 46345](https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/46345/consoleFull)) (duplicated because I run the build twice with different profiles):

> Checkstyle checks failed at following occurrences:
[ERROR] src/main/java/org/apache/spark/sql/execution/datasources/parquet/UnsafeRowParquetRecordReader.java:[217,7] (coding) MissingSwitchDefault: switch without "default" clause.
> [ERROR] src/main/java/org/apache/spark/sql/execution/datasources/parquet/SpecificParquetRecordReaderBase.java:[198,10] (modifier) ModifierOrder: 'protected' modifier out of order with the JLS suggestions.
> [ERROR] src/main/java/org/apache/spark/sql/execution/datasources/parquet/UnsafeRowParquetRecordReader.java:[217,7] (coding) MissingSwitchDefault: switch without "default" clause.
> [ERROR] src/main/java/org/apache/spark/sql/execution/datasources/parquet/SpecificParquetRecordReaderBase.java:[198,10] (modifier) ModifierOrder: 'protected' modifier out of order with the JLS suggestions.
> [error] running /home/jenkins/workspace/SparkPullRequestBuilder2/dev/lint-java ; received return code 1

Also fix some of the minor violations that didn't require sweeping changes.

Apologies for the previous botched PRs - I finally figured out the issue.

cr: JoshRosen, pwendell

> I state that the contribution is my original work, and I license the work to the project under the project's open source license.

Author: Dmitry Erastov <derastov@gmail.com>

Closes #9867 from dskrvk/master.

This bug was exposed as memory corruption in Timsort which uses copyMemory to copy
large regions that can overlap. The prior implementation did not handle this case
half the time and always copied forward, resulting in the data being corrupt.

Author: Nong Li <nong@databricks.com>

Closes #10068 from nongli/spark-12030.

The default implementation of serialization UTF8String with Kyro may be not correct (BYTE_ARRAY_OFFSET could be different across JVM)

Author: Davies Liu <davies@databricks.com>

Closes #9704 from davies/kyro_string.

This brings the support of off-heap memory for array inside BytesToBytesMap and InMemorySorter, then we could allocate all the memory from off-heap for execution.

Closes #8068

Author: Davies Liu <davies@databricks.com>

Closes #9477 from davies/unsafe_timsort.

Since we have 4 bytes as number of records in the beginning of a page, the address can not be zero, so we do not need the bitset.

For performance concerns, the bitset could help speed up false lookup if the slot is empty (because bitset is smaller than longArray, cache hit rate will be higher). In practice, the map is filled with 35% - 70% (use 50% as average), so only half of the false lookups can benefit of it, all others will pay the cost of load the bitset (still need to access the longArray anyway).

For aggregation, we always need to access the longArray (insert a new key after false lookup), also confirmed by a benchmark.

 For broadcast hash join, there could be a regression, but a simple benchmark showed that it may not (most of lookup are false):

```
sqlContext.range(1<<20).write.parquet("small")
df = sqlContext.read.parquet('small')
for i in range(3):
    t = time.time()
    df2 = sqlContext.range(1<<26).selectExpr("id * 1111111111 % 987654321 as id2")
    df2.join(df, df.id == df2.id2).count()
    print time.time() -t
```

Having bitset (used time in seconds):
```
17.5404241085
10.2758829594
10.5786800385
```
After removing bitset (used time in seconds):
```
21.8939979076
12.4132959843
9.97224712372
```

cc rxin nongli

Author: Davies Liu <davies@databricks.com>

Closes #9452 from davies/remove_bitset.

Replace use of `junit.framework` with `org.junit`, and touch up tests in question

Author: Sean Owen <sowen@cloudera.com>

Closes #9411 from srowen/SPARK-11456.

This PR introduce a mechanism to call spill() on those SQL operators that support spilling (for example, BytesToBytesMap, UnsafeExternalSorter and ShuffleExternalSorter) if there is not enough memory for execution. The preserved first page is needed anymore, so removed.

Other Spillable objects in Spark core (ExternalSorter and AppendOnlyMap) are not included in this PR, but those could benefit from this (trigger others' spilling).

The PrepareRDD may be not needed anymore, could be removed in follow up PR.

The following script will fail with OOM before this PR, finished in 150 seconds with 2G heap (also works in 1.5 branch, with similar duration).

```python
sqlContext.setConf("spark.sql.shuffle.partitions", "1")
df = sqlContext.range(1<<25).selectExpr("id", "repeat(id, 2) as s")
df2 = df.select(df.id.alias('id2'), df.s.alias('s2'))
j = df.join(df2, df.id==df2.id2).groupBy(df.id).max("id", "id2")
j.explain()
print j.count()
```

For thread-safety, here what I'm got:

1) Without calling spill(), the operators should only be used by single thread, no safety problems.

2) spill() could be triggered in two cases, triggered by itself, or by other operators. we can check trigger == this in spill(), so it's still in the same thread, so safety problems.

3) if it's triggered by other operators (right now cache will not trigger spill()), we only spill the data into disk when it's in scanning stage (building is finished), so the in-memory sorter or memory pages are read-only, we only need to synchronize the iterator and change it.

4) During scanning, the iterator will only use one record in one page, we can't free this page, because the downstream is currently using it (used by UnsafeRow or other objects). In BytesToBytesMap, we just skip the current page, and dump all others into disk. In UnsafeExternalSorter, we keep the page that is used by current record (having the same baseObject), free it when loading the next record. In ShuffleExternalSorter, the spill() will not trigger during scanning.

5) In order to avoid deadlock, we didn't call acquireMemory during spill (so we reused the pointer array in InMemorySorter).

Author: Davies Liu <davies@databricks.com>

Closes #9241 from davies/force_spill.

This patch refactors the MemoryManager class structure. After #9000, Spark had the following classes:

- MemoryManager
- StaticMemoryManager
- ExecutorMemoryManager
- TaskMemoryManager
- ShuffleMemoryManager

This is fairly confusing. To simplify things, this patch consolidates several of these classes:

- ShuffleMemoryManager and ExecutorMemoryManager were merged into MemoryManager.
- TaskMemoryManager is moved into Spark Core.

**Key changes and tasks**:

- [x] Merge ExecutorMemoryManager into MemoryManager.
  - [x] Move pooling logic into Allocator.
- [x] Move TaskMemoryManager from `spark-unsafe` to `spark-core`.
- [x] Refactor the existing Tungsten TaskMemoryManager interactions so Tungsten code use only this and not both this and ShuffleMemoryManager.
- [x] Refactor non-Tungsten code to use the TaskMemoryManager instead of ShuffleMemoryManager.
- [x] Merge ShuffleMemoryManager into MemoryManager.
  - [x] Move code
  - [x] ~~Simplify 1/n calculation.~~ **Will defer to followup, since this needs more work.**
- [x] Port ShuffleMemoryManagerSuite tests.
- [x] Move classes from `unsafe` package to `memory` package.
- [ ] Figure out how to handle the hacky use of the memory managers in HashedRelation's broadcast variable construction.
- [x] Test porting and cleanup: several tests relied on mock functionality (such as `TestShuffleMemoryManager.markAsOutOfMemory`) which has been changed or broken during the memory manager consolidation
  - [x] AbstractBytesToBytesMapSuite
  - [x] UnsafeExternalSorterSuite
  - [x] UnsafeFixedWidthAggregationMapSuite
  - [x] UnsafeKVExternalSorterSuite

**Compatiblity notes**:

- This patch introduces breaking changes in `ExternalAppendOnlyMap`, which is marked as `DevloperAPI` (likely for legacy reasons): this class now cannot be used outside of a task.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #9127 from JoshRosen/SPARK-10984.

This PR improve the unrolling and read of complex types in columnar cache:
1) Using UnsafeProjection to do serialization of complex types, so they will not be serialized three times (two for actualSize)
2) Copy the bytes from UnsafeRow/UnsafeArrayData to ByteBuffer directly, avoiding the immediate byte[]
3) Using the underlying array in ByteBuffer to create UTF8String/UnsafeRow/UnsafeArrayData without copy.

Combine these optimizations,  we can reduce the unrolling time from 25s to 21s (20% less), reduce the scanning time from 3.5s to 2.5s (28% less).

```
df = sqlContext.read.parquet(path)
t = time.time()
df.cache()
df.count()
print 'unrolling', time.time() - t

for i in range(10):
    t = time.time()
    print df.select("*")._jdf.queryExecution().toRdd().count()
    print time.time() - t
```

The schema is
```
root
 |-- a: struct (nullable = true)
 |    |-- b: long (nullable = true)
 |    |-- c: string (nullable = true)
 |-- d: array (nullable = true)
 |    |-- element: long (containsNull = true)
 |-- e: map (nullable = true)
 |    |-- key: long
 |    |-- value: string (valueContainsNull = true)
```

Now the columnar cache depends on that UnsafeProjection support all the data types (including UDT), this PR also fix that.

Author: Davies Liu <davies@databricks.com>

Closes #9016 from davies/complex2.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #8775 from vanzin/SPARK-10300.

The utilities such as Substring#substringBinarySQL and BinaryPrefixComparator#computePrefix for binary data are put together in ByteArray for easy-to-read.

Author: Takeshi YAMAMURO <linguin.m.s@gmail.com>

Closes #8122 from maropu/CleanUpForBinaryType.

This reverts commit 8abef21d.

This change does two things:

- tag a few tests and adds the mechanism in the build to be able to disable those tags,
  both in maven and sbt, for both junit and scalatest suites.
- add some logic to run-tests.py to disable some tags depending on what files have
  changed; that's used to disable expensive tests when a module hasn't explicitly
  been changed, to speed up testing for changes that don't directly affect those
  modules.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #8437 from vanzin/test-tags.

Author: Reynold Xin <rxin@databricks.com>

Closes #8350 from rxin/1.6.

CC rxin marmbrus

Author: Feynman Liang <fliang@databricks.com>

Closes #8523 from feynmanliang/SPARK-10351.

In UnsafeRow, we use the private field of BigInteger for better performance, but it actually didn't contribute much (3% in one benchmark) to end-to-end runtime, and make it not portable (may fail on other JVM implementations).

So we should use the public API instead.

cc rxin

Author: Davies Liu <davies@databricks.com>

Closes #8286 from davies/portable_decimal.

Tiny modification to a few comments ```sbt publishLocal``` work again.

Author: Herman van Hovell <hvanhovell@questtec.nl>

Closes #8209 from hvanhovell/SPARK-9980.

The BYTE_ARRAY_OFFSET could be different in JVM with different configurations (for example, different heap size, 24 if heap > 32G, otherwise 16), so offset of UTF8String is not portable, we should handler that during serialization.

Author: Davies Liu <davies@databricks.com>

Closes #8210 from davies/serialize_utf8string.

Currently, we access the `page.pageNumer` after it's freed, that could be modified by other thread, cause NPE.

The same TaskMemoryManager could be used by multiple threads (for example, Python UDF and TransportScript), so it should be thread safe to allocate/free memory/page. The underlying Bitset and HashSet are not thread safe, we should put them inside a synchronized block.

cc JoshRosen

Author: Davies Liu <davies@databricks.com>

Closes #8177 from davies/memory_manager.

PlatformDependent.UNSAFE is way too verbose.

Author: Reynold Xin <rxin@databricks.com>

Closes #8094 from rxin/SPARK-9815 and squashes the following commits:

229b603 [Reynold Xin] [SPARK-9815] Rename PlatformDependent.UNSAFE -> Platform.

This PR enables converting interval term in HiveQL to CalendarInterval Literal.

JIRA: https://issues.apache.org/jira/browse/SPARK-9728

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

Closes #8034 from yjshen/interval_hiveql and squashes the following commits:

7fe9a5e [Yijie Shen] declare throw exception and add unit test
fce7795 [Yijie Shen] convert hiveql interval term into CalendarInterval literal

Previously, we use 64MB as the default page size, which was way too big for a lot of Spark applications (especially for single node).

This patch changes it so that the default page size, if unset by the user, is determined by the number of cores available and the total execution memory available.

Author: Reynold Xin <rxin@databricks.com>

Closes #8012 from rxin/pagesize and squashes the following commits:

16f4756 [Reynold Xin] Fixed failing test.
5afd570 [Reynold Xin] private...
0d5fb98 [Reynold Xin] Update default value.
674a6cd [Reynold Xin] Address review feedback.
dc00e05 [Reynold Xin] Merge with master.
73ebdb6 [Reynold Xin] [SPARK-9700] Pick default page size more intelligently.

In order to support update a varlength (actually fixed length) object, the space should be preserved even  it's null. And, we can't call setNullAt(i) for it anymore, we because setNullAt(i) will remove the offset of the preserved space, should call setDecimal(i, null, precision) instead.

After this, we can do hash based aggregation on DecimalType with precision > 18. In a tests, this could decrease the end-to-end run time of aggregation query from 37 seconds (sort based) to 24 seconds (hash based).

cc rxin

Author: Davies Liu <davies@databricks.com>

Closes #7978 from davies/update_decimal and squashes the following commits:

bed8100 [Davies Liu] isSettable -> isMutable
923c9eb [Davies Liu] address comments and fix bug
385891d [Davies Liu] Merge branch 'master' of github.com:apache/spark into update_decimal
36a1872 [Davies Liu] fix tests
cd6c524 [Davies Liu] support set decimal with precision > 18

![translate](http://www.w3resource.com/PostgreSQL/postgresql-translate-function.png)

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

Closes #7709 from zhichao-li/translate and squashes the following commits:

9418088 [zhichao.li] refine checking condition
f2ab77a [zhichao.li] clone string
9d88f2d [zhichao.li] fix indent
6aa2962 [zhichao.li] style
e575ead [zhichao.li] add python api
9d4bab0 [zhichao.li] add special case for fodable and refactor unittest
eda7ad6 [zhichao.li] update to use TernaryExpression
cdfd4be [zhichao.li] add function translate

This patch extends UnsafeExternalSorter to support records larger than the page size. The basic strategy is the same as in #7762: store large records in their own overflow pages.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #7891 from JoshRosen/large-records-in-sql-sorter and squashes the following commits:

967580b [Josh Rosen] Merge remote-tracking branch 'origin/master' into large-records-in-sql-sorter
948c344 [Josh Rosen] Add large records tests for KV sorter.
3c17288 [Josh Rosen] Combine memory and disk cleanup into general cleanupResources() method
380f217 [Josh Rosen] Merge remote-tracking branch 'origin/master' into large-records-in-sql-sorter
27eafa0 [Josh Rosen] Fix page size in PackedRecordPointerSuite
a49baef [Josh Rosen] Address initial round of review comments
3edb931 [Josh Rosen] Remove accidentally-committed debug statements.
2b164e2 [Josh Rosen] Support large records in UnsafeExternalSorter.

This PR is based on #7186 (just fix the conflict), thanks to tarekauel .

find_in_set(string str, string strList): int

Returns the first occurance of str in strList where strList is a comma-delimited string. Returns null if either argument is null. Returns 0 if the first argument contains any commas. For example, find_in_set('ab', 'abc,b,ab,c,def') returns 3.

Only add this to SQL, not DataFrame.

Closes #7186

Author: Tarek Auel <tarek.auel@googlemail.com>
Author: Davies Liu <davies@databricks.com>

Closes #7900 from davies/find_in_set and squashes the following commits:

4334209 [Davies Liu] Merge branch 'master' of github.com:apache/spark into find_in_set
8f00572 [Davies Liu] Merge branch 'master' of github.com:apache/spark into find_in_set
243ede4 [Tarek Auel] [SPARK-8244][SQL] hive compatibility
1aaf64e [Tarek Auel] [SPARK-8244][SQL] unit test fix
e4093a4 [Tarek Auel] [SPARK-8244][SQL] final modifier for COMMA_UTF8
0d05df5 [Tarek Auel] Merge branch 'master' into SPARK-8244
208d710 [Tarek Auel] [SPARK-8244] address comments & bug fix
71b2e69 [Tarek Auel] [SPARK-8244] find_in_set
66c7fda [Tarek Auel] Merge branch 'master' into SPARK-8244
61b8ca2 [Tarek Auel] [SPARK-8224] removed loop and split; use unsafe String comparison
4f75a65 [Tarek Auel] Merge branch 'master' into SPARK-8244
e3b20c8 [Tarek Auel] [SPARK-8244] added type check
1c2bbb7 [Tarek Auel] [SPARK-8244] findInSet

Previous code assumed little-endian.

Author: Matthew Brandyberry <mbrandy@us.ibm.com>

Closes #7902 from mtbrandy/SPARK-9483 and squashes the following commits:

ec31df8 [Matthew Brandyberry] [SPARK-9483] Changes from review comments.
17d54c6 [Matthew Brandyberry] [SPARK-9483] Fix UTF8String.getPrefix for big-endian.

This PR adds a UnsafeArrayData, current we encode it in this way:

first 4 bytes is the # elements
then each 4 byte is the start offset of the element, unless it is negative, in which case the element is null.
followed by the elements themselves

an example:  [10, 11, 12, 13, null, 14] will be encoded as:
5, 28, 32, 36, 40, -44, 44, 10, 11, 12, 13, 14

Note that, when we read a UnsafeArrayData from bytes, we can read the first 4 bytes as numElements and take the rest(first 4 bytes skipped) as value region.

unsafe map data just use 2 unsafe array data, first 4 bytes is # of elements, second 4 bytes is numBytes of key array, the follows key array data and value array data.

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #7752 from cloud-fan/unsafe-array and squashes the following commits:

3269bd7 [Wenchen Fan] fix a bug
6445289 [Wenchen Fan] add unit tests
49adf26 [Wenchen Fan] add unsafe map
20d1039 [Wenchen Fan] add comments and unsafe converter
821b8db [Wenchen Fan] add unsafe array

The detailed approach is documented in UnsafeKVExternalSorterSuite.testKVSorter(), working as follows:

1. Create input by generating data randomly based on the given key/value schema (which is also randomly drawn from a list of candidate types)
2. Run UnsafeKVExternalSorter on the generated data
3. Collect the output from the sorter, and make sure the keys are sorted in ascending order
4. Sort the input by both key and value, and sort the sorter output also by both key and value. Compare the sorted input and sorted output together to make sure all the key/values match.
5. Check memory allocation to make sure there is no memory leak.

There is also a spill flag. When set to true, the sorter will spill probabilistically roughly every 100 records.

Author: Reynold Xin <rxin@databricks.com>

Closes #7873 from rxin/kvsorter-randomized-test and squashes the following commits:

a08c251 [Reynold Xin] Resource cleanup.
0488b5c [Reynold Xin] [SPARK-9543][SQL] Add randomized testing for UnsafeKVExternalSorter.

When accessing a column in UnsafeRow, it's good to avoid the copy, then we should do deep copy when turn the UnsafeRow into generic Row, this PR brings generated FromUnsafeProjection to do that.

This PR also fix the expressions that cache the UTF8String, which should also copy it.

Author: Davies Liu <davies@databricks.com>

Closes #7840 from davies/avoid_copy and squashes the following commits:

230c8a1 [Davies Liu] address comment
fd797c9 [Davies Liu] Merge branch 'master' of github.com:apache/spark into avoid_copy
e095dd0 [Davies Liu] rollback rename
8ef5b0b [Davies Liu] copy String in Columnar
81360b8 [Davies Liu] fix class name
9aecb88 [Davies Liu] use FromUnsafeProjection to do deep copy for UTF8String and struct

This PR is based on #7208 , thanks to HuJiayin

Closes #7208

Author: HuJiayin <jiayin.hu@intel.com>
Author: Davies Liu <davies@databricks.com>

Closes #7850 from davies/initcap and squashes the following commits:

54472e9 [Davies Liu] fix python test
17ffe51 [Davies Liu] Merge branch 'master' of github.com:apache/spark into initcap
ca46390 [Davies Liu] Merge branch 'master' of github.com:apache/spark into initcap
3a906e4 [Davies Liu] implement title case in UTF8String
8b2506a [HuJiayin] Update functions.py
2cd43e5 [HuJiayin] fix python style check
b616c0e [HuJiayin] add python api
1f5a0ef [HuJiayin] add codegen
7e0c604 [HuJiayin] Merge branch 'master' of https://github.com/apache/spark into initcap
6a0b958 [HuJiayin] add column
c79482d [HuJiayin] support soundex
7ce416b [HuJiayin] support initcap rebase code

This pull request adds a sortedIterator method to UnsafeFixedWidthAggregationMap that sorts its data in-place by the grouping key.

This is needed so we can fallback to external sorting for aggregation.

Author: Reynold Xin <rxin@databricks.com>

Closes #7849 from rxin/bytes2bytes-sorting and squashes the following commits:

75018c6 [Reynold Xin] Updated documentation.
81a8694 [Reynold Xin] [SPARK-9520][SQL] Support in-place sort in UnsafeFixedWidthAggregationMap.

This is based on #7641, thanks to zhichao-li

Closes #7641

Author: zhichao.li <zhichao.li@intel.com>
Author: Davies Liu <davies@databricks.com>

Closes #7848 from davies/substr and squashes the following commits:

461b709 [Davies Liu] remove bytearry from tests
b45377a [Davies Liu] Merge branch 'master' of github.com:apache/spark into substr
01d795e [zhichao.li] scala style
99aa130 [zhichao.li] add substring to dataframe
4f68bfe [zhichao.li] add binary type support for substring

BytesToBytesMap current encodes key/value data in the following format:
```
8B key length, key data, 8B value length, value data
```

UnsafeExternalSorter, on the other hand, encodes data this way:
```
4B record length, data
```

As a result, we cannot pass records encoded by BytesToBytesMap directly into UnsafeExternalSorter for sorting. However, if we rearrange data slightly, we can then pass the key/value records directly into UnsafeExternalSorter:
```
4B key+value length, 4B key length, key data, value data
```

Author: Reynold Xin <rxin@databricks.com>

Closes #7845 from rxin/kvsort-rebase and squashes the following commits:

5716b59 [Reynold Xin] Fixed test.
2e62ccb [Reynold Xin] Updated BytesToBytesMap's data encoding to put the key first.
a51b641 [Reynold Xin] Added a KV sorter interface.

This PR is based on the original work by JoshRosen in #7780, which adds ScalaCheck property-based tests for UTF8String.

Author: Josh Rosen <joshrosen@databricks.com>
Author: Yijie Shen <henry.yijieshen@gmail.com>

Closes #7830 from yjshen/utf8-property-checks and squashes the following commits:

593da3a [Yijie Shen] resolve comments
c0800e6 [Yijie Shen] Finish all todos in suite
52f51a0 [Josh Rosen] Add some more failing tests
49ed0697 [Josh Rosen] Rename suite
9209c64 [Josh Rosen] UTF8String Property Checks.

This PR is based on #7533 , thanks to zhichao-li

Closes #7533

Author: zhichao.li <zhichao.li@intel.com>
Author: Davies Liu <davies@databricks.com>

Closes #7843 from davies/str_index and squashes the following commits:

391347b [Davies Liu] add python api
3ce7802 [Davies Liu] fix substringIndex
f2d29a1 [Davies Liu] Merge branch 'master' of github.com:apache/spark into str_index
515519b [zhichao.li] add foldable and remove null checking
9546991 [zhichao.li] scala style
67c253a [zhichao.li] hide some apis and clean code
b19b013 [zhichao.li] add codegen and clean code
ac863e9 [zhichao.li] reduce the calling of numChars
12e108f [zhichao.li] refine unittest
d92951b [zhichao.li] add lastIndexOf
52d7b03 [zhichao.li] add substring_index function

[SPARK-9451] [SQL] Support entries larger than default page size in BytesToBytesMap & integrate with ShuffleMemoryManager

This patch adds support for entries larger than the default page size in BytesToBytesMap.  These large rows are handled by allocating special overflow pages to hold individual entries.

In addition, this patch integrates BytesToBytesMap with the ShuffleMemoryManager:

- Move BytesToBytesMap from `unsafe` to `core` so that it can import `ShuffleMemoryManager`.
- Before allocating new data pages, ask the ShuffleMemoryManager to reserve the memory:
  - `putNewKey()` now returns a boolean to indicate whether the insert succeeded or failed due to a lack of memory.  The caller can use this value to respond to the memory pressure (e.g. by spilling).
- `UnsafeFixedWidthAggregationMap. getAggregationBuffer()` now returns `null` to signal failure due to a lack of memory.
- Updated all uses of these classes to handle these error conditions.
- Added new tests for allocating large records and for allocations which fail due to memory pressure.
- Extended the `afterAll()` test teardown methods to detect ShuffleMemoryManager leaks.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #7762 from JoshRosen/large-rows and squashes the following commits:

ae7bc56 [Josh Rosen] Fix compilation
82fc657 [Josh Rosen] Merge remote-tracking branch 'origin/master' into large-rows
34ab943 [Josh Rosen] Remove semi
31a525a [Josh Rosen] Integrate BytesToBytesMap with ShuffleMemoryManager.
626b33c [Josh Rosen] Move code to sql/core and spark/core packages so that ShuffleMemoryManager can be integrated
ec4484c [Josh Rosen] Move BytesToBytesMap from unsafe package to core.
642ed69 [Josh Rosen] Rename size to numElements
bea1152 [Josh Rosen] Add basic test.
2cd3570 [Josh Rosen] Remove accidental duplicated code
07ff9ef [Josh Rosen] Basic support for large rows in BytesToBytesMap.

This PR brings SQL function soundex(), see https://issues.apache.org/jira/browse/HIVE-9738

It's based on #7115 , thanks to HuJiayin

Author: HuJiayin <jiayin.hu@intel.com>
Author: Davies Liu <davies@databricks.com>

Closes #7812 from davies/soundex and squashes the following commits:

fa75941 [Davies Liu] Merge branch 'master' of github.com:apache/spark into soundex
a4bd6d8 [Davies Liu] fix soundex
2538908 [HuJiayin] add codegen soundex
d15d329 [HuJiayin] add back ut
ded1a14 [HuJiayin] Merge branch 'master' of https://github.com/apache/spark
e2dec2c [HuJiayin] support soundex rebase code

Previously we could be getting garbage data if the number of bytes is 0, or on JVMs that are 4 byte aligned, or when compressedoops is on.

Author: Reynold Xin <rxin@databricks.com>

Closes #7789 from rxin/utf8string and squashes the following commits:

86ffa3e [Reynold Xin] Mask out data outside of valid range.
4d647ed [Reynold Xin] Mask out data.
c6e8794 [Reynold Xin] [SPARK-9460] Fix prefix generation for UTF8String.

As of today, StringPrefixComparator converts the long values back to byte arrays in order to compare them. This patch optimizes this to compare the longs directly, rather than turning the longs into byte arrays and comparing them byte by byte (unsigned).

This only works on little-endian architecture right now.

Author: Reynold Xin <rxin@databricks.com>

Closes #7765 from rxin/SPARK-9460 and squashes the following commits:

e4908cc [Reynold Xin] Stricter randomized tests.
4c8d094 [Reynold Xin] [SPARK-9460] Avoid byte array allocation in StringPrefixComparator.