[SPARK-3294][SQL] Eliminates boxing costs from in-memory columnar sto…

…rage

This is a major refactoring of the in-memory columnar storage implementation, aims to eliminate boxing costs from critical paths (building/accessing column buffers) as much as possible. The basic idea is to refactor all major interfaces into a row-based form and use them together with `SpecificMutableRow`. The difficult part is how to adapt all compression schemes, esp. `RunLengthEncoding` and `DictionaryEncoding`, to this design. Since in-memory compression is disabled by default for now, and this PR should be strictly better than before no matter in-memory compression is enabled or not, maybe I'll finish that part in another PR.

**UPDATE** This PR also took the chance to optimize `HiveTableScan` by

1. leveraging `SpecificMutableRow` to avoid boxing cost, and
1. building specific `Writable` unwrapper functions a head of time to avoid per row pattern matching and branching costs.

TODO

- [x] Benchmark
- [ ] ~~Eliminate boxing costs in `RunLengthEncoding`~~ (left to future PRs)
- [ ] ~~Eliminate boxing costs in `DictionaryEncoding` (seems not easy to do without specializing `DictionaryEncoding` for every supported column type)~~  (left to future PRs)

## Micro benchmark

The benchmark uses a 10 million line CSV table consists of bytes, shorts, integers, longs, floats and doubles, measures the time to build the in-memory version of this table, and the time to scan the whole in-memory table.

Benchmark code can be found [here](https://gist.github.com/liancheng/fe70a148de82e77bd2c8#file-hivetablescanbenchmark-scala). Script used to generate the input table can be found [here](https://gist.github.com/liancheng/fe70a148de82e77bd2c8#file-tablegen-scala).

Speedup:

- Hive table scanning + column buffer building: **18.74%**

  The original benchmark uses 1K as in-memory batch size, when increased to 10K, it can be 28.32% faster.

- In-memory table scanning: **7.95%**

Before:

        | Building | Scanning
------- | -------- | --------
1       | 16472    | 525
2       | 16168    | 530
3       | 16386    | 529
4       | 16184    | 538
5       | 16209    | 521
Average | 16283.8  | 528.6

After:

        | Building | Scanning
------- | -------- | --------
1       | 13124    | 458
2       | 13260    | 529
3       | 12981    | 463
4       | 13214    | 483
5       | 13583    | 500
Average | 13232.4  | 486.6

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

Closes #2327 from liancheng/prevent-boxing/unboxing and squashes the following commits:

4419fe4 [Cheng Lian] Addressing comments
e5d2cf2 [Cheng Lian] Bug fix: should call setNullAt when field value is null to avoid NPE
8b8552b [Cheng Lian] Only checks for partition batch pruning flag once
489f97b [Cheng Lian] Bug fix: TableReader.fillObject uses wrong ordinals
97bbc4e [Cheng Lian] Optimizes hive.TableReader by by providing specific Writable unwrappers a head of time
3dc1f94 [Cheng Lian] Minor changes to eliminate row object creation
5b39cb9 [Cheng Lian] Lowers log level of compression scheme details
f2a7890 [Cheng Lian] Use SpecificMutableRow in InMemoryColumnarTableScan to avoid boxing
9cf30b0 [Cheng Lian] Added row based ColumnType.append/extract
456c366 [Cheng Lian] Made compression decoder row based
edac3cd [Cheng Lian] Makes ColumnAccessor.extractSingle row based
8216936 [Cheng Lian] Removes boxing cost in IntDelta and LongDelta by providing specialized implementations
b70d519 [Cheng Lian] Made some in-memory columnar storage interfaces row-based

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/SpecificRow.scala

@@ -171,7 +171,7 @@ final class MutableByte extends MutableValue {
 }
 
 final class MutableAny extends MutableValue {
-  var value: Any = 0
+  var value: Any = _
   def boxed = if (isNull) null else value
   def update(v: Any) = value = {
     isNull = false

sql/core/src/main/scala/org/apache/spark/sql/columnar/ColumnAccessor.scala

@@ -50,11 +50,13 @@ private[sql] abstract class BasicColumnAccessor[T <: DataType, JvmType](
 
   def hasNext = buffer.hasRemaining
 
-  def extractTo(row: MutableRow, ordinal: Int) {
-    columnType.setField(row, ordinal, extractSingle(buffer))
+  def extractTo(row: MutableRow, ordinal: Int): Unit = {
+    extractSingle(row, ordinal)
   }
 
-  def extractSingle(buffer: ByteBuffer): JvmType = columnType.extract(buffer)
+  def extractSingle(row: MutableRow, ordinal: Int): Unit = {
+    columnType.extract(buffer, row, ordinal)
+  }
 
   protected def underlyingBuffer = buffer
 }

sql/core/src/main/scala/org/apache/spark/sql/columnar/ColumnBuilder.scala

@@ -68,10 +68,9 @@ private[sql] class BasicColumnBuilder[T <: DataType, JvmType](
     buffer.order(ByteOrder.nativeOrder()).putInt(columnType.typeId)
   }
 
-  override def appendFrom(row: Row, ordinal: Int) {
-    val field = columnType.getField(row, ordinal)
-    buffer = ensureFreeSpace(buffer, columnType.actualSize(field))
-    columnType.append(field, buffer)
+  override def appendFrom(row: Row, ordinal: Int): Unit = {
+    buffer = ensureFreeSpace(buffer, columnType.actualSize(row, ordinal))
+    columnType.append(row, ordinal, buffer)
   }
 
   override def build() = {
@@ -142,16 +141,16 @@ private[sql] object ColumnBuilder {
       useCompression: Boolean = false): ColumnBuilder = {
 
     val builder = (typeId match {
-      case INT.typeId     => new IntColumnBuilder
-      case LONG.typeId    => new LongColumnBuilder
-      case FLOAT.typeId   => new FloatColumnBuilder
-      case DOUBLE.typeId  => new DoubleColumnBuilder
-      case BOOLEAN.typeId => new BooleanColumnBuilder
-      case BYTE.typeId    => new ByteColumnBuilder
-      case SHORT.typeId   => new ShortColumnBuilder
-      case STRING.typeId  => new StringColumnBuilder
-      case BINARY.typeId  => new BinaryColumnBuilder
-      case GENERIC.typeId => new GenericColumnBuilder
+      case INT.typeId       => new IntColumnBuilder
+      case LONG.typeId      => new LongColumnBuilder
+      case FLOAT.typeId     => new FloatColumnBuilder
+      case DOUBLE.typeId    => new DoubleColumnBuilder
+      case BOOLEAN.typeId   => new BooleanColumnBuilder
+      case BYTE.typeId      => new ByteColumnBuilder
+      case SHORT.typeId     => new ShortColumnBuilder
+      case STRING.typeId    => new StringColumnBuilder
+      case BINARY.typeId    => new BinaryColumnBuilder
+      case GENERIC.typeId   => new GenericColumnBuilder
       case TIMESTAMP.typeId => new TimestampColumnBuilder
     }).asInstanceOf[ColumnBuilder]
 

sql/core/src/main/scala/org/apache/spark/sql/columnar/ColumnStats.scala

@@ -69,7 +69,7 @@ private[sql] class ByteColumnStats extends ColumnStats {
   var lower = Byte.MaxValue
   var nullCount = 0
 
-  override def gatherStats(row: Row, ordinal: Int) {
+  override def gatherStats(row: Row, ordinal: Int): Unit = {
     if (!row.isNullAt(ordinal)) {
       val value = row.getByte(ordinal)
       if (value > upper) upper = value
@@ -87,7 +87,7 @@ private[sql] class ShortColumnStats extends ColumnStats {
   var lower = Short.MaxValue
   var nullCount = 0
 
-  override def gatherStats(row: Row, ordinal: Int) {
+  override def gatherStats(row: Row, ordinal: Int): Unit = {
     if (!row.isNullAt(ordinal)) {
       val value = row.getShort(ordinal)
       if (value > upper) upper = value
@@ -105,7 +105,7 @@ private[sql] class LongColumnStats extends ColumnStats {
   var lower = Long.MaxValue
   var nullCount = 0
 
-  override def gatherStats(row: Row, ordinal: Int) {
+  override def gatherStats(row: Row, ordinal: Int): Unit = {
     if (!row.isNullAt(ordinal)) {
       val value = row.getLong(ordinal)
       if (value > upper) upper = value
@@ -123,7 +123,7 @@ private[sql] class DoubleColumnStats extends ColumnStats {
   var lower = Double.MaxValue
   var nullCount = 0
 
-  override def gatherStats(row: Row, ordinal: Int) {
+  override def gatherStats(row: Row, ordinal: Int): Unit = {
     if (!row.isNullAt(ordinal)) {
       val value = row.getDouble(ordinal)
       if (value > upper) upper = value
@@ -141,7 +141,7 @@ private[sql] class FloatColumnStats extends ColumnStats {
   var lower = Float.MaxValue
   var nullCount = 0
 
-  override def gatherStats(row: Row, ordinal: Int) {
+  override def gatherStats(row: Row, ordinal: Int): Unit = {
     if (!row.isNullAt(ordinal)) {
       val value = row.getFloat(ordinal)
       if (value > upper) upper = value
@@ -159,7 +159,7 @@ private[sql] class IntColumnStats extends ColumnStats {
   var lower = Int.MaxValue
   var nullCount = 0
 
-  override def gatherStats(row: Row, ordinal: Int) {
+  override def gatherStats(row: Row, ordinal: Int): Unit = {
     if (!row.isNullAt(ordinal)) {
       val value = row.getInt(ordinal)
       if (value > upper) upper = value
@@ -177,7 +177,7 @@ private[sql] class StringColumnStats extends ColumnStats {
   var lower: String = null
   var nullCount = 0
 
-  override def gatherStats(row: Row, ordinal: Int) {
+  override def gatherStats(row: Row, ordinal: Int): Unit = {
     if (!row.isNullAt(ordinal)) {
       val value = row.getString(ordinal)
       if (upper == null || value.compareTo(upper) > 0) upper = value
@@ -195,7 +195,7 @@ private[sql] class TimestampColumnStats extends ColumnStats {
   var lower: Timestamp = null
   var nullCount = 0
 
-  override def gatherStats(row: Row, ordinal: Int) {
+  override def gatherStats(row: Row, ordinal: Int): Unit = {
     if (!row.isNullAt(ordinal)) {
       val value = row(ordinal).asInstanceOf[Timestamp]
       if (upper == null || value.compareTo(upper) > 0) upper = value