[SPARK-7913] [CORE] Increase the maximum capacity of PartitionedPairBuffe,...

[SPARK-7913] [CORE] Increase the maximum capacity of PartitionedPairBuffe, PartitionedSerializedPairBuffer and AppendOnlyMap

The previous growing strategy is alway doubling the capacity.

This PR adjusts the growing strategy: doubling the capacity but if overflow, use the maximum capacity as the new capacity. It increases the maximum capacity of PartitionedPairBuffer from `2 ^ 29` to `2 ^ 30 - 1`, the maximum capacity of PartitionedSerializedPairBuffer from `2 ^ 28` to `(2 ^ 29) - 1`, and the maximum capacity of AppendOnlyMap from `0.7 * (2 ^ 29)` to `(2 ^ 29)`.

Author: zsxwing <zsxwing@gmail.com>

Closes #6456 from zsxwing/SPARK-7913 and squashes the following commits:

abcb932 [zsxwing] Address comments
e30b61b [zsxwing] Increase the maximum capacity of AppendOnlyMap
05b6420 [zsxwing] Update the exception message
64fe227 [zsxwing] Increase the maximum capacity of PartitionedPairBuffer and PartitionedSerializedPairBuffer

core/src/main/scala/org/apache/spark/util/collection/AppendOnlyMap.scala

@@ -32,12 +32,18 @@ import org.apache.spark.annotation.DeveloperApi
  * size, which is guaranteed to explore all spaces for each key (see
  * http://en.wikipedia.org/wiki/Quadratic_probing).
  *
+ * The map can support up to `536870912 (2 ^ 29)` elements.
+ *
  * TODO: Cache the hash values of each key? java.util.HashMap does that.
  */
 @DeveloperApi
 class AppendOnlyMap[K, V](initialCapacity: Int = 64)
   extends Iterable[(K, V)] with Serializable {
-  require(initialCapacity <= (1 << 29), "Can't make capacity bigger than 2^29 elements")
+
+  import AppendOnlyMap._
+
+  require(initialCapacity <= MAXIMUM_CAPACITY,
+    s"Can't make capacity bigger than ${MAXIMUM_CAPACITY} elements")
   require(initialCapacity >= 1, "Invalid initial capacity")
 
   private val LOAD_FACTOR = 0.7
@@ -193,8 +199,11 @@ class AppendOnlyMap[K, V](initialCapacity: Int = 64)
 
   /** Increase table size by 1, rehashing if necessary */
   private def incrementSize() {
+    if (curSize == MAXIMUM_CAPACITY) {
+      throw new IllegalStateException(s"Can't put more that ${MAXIMUM_CAPACITY} elements")
+    }
     curSize += 1
-    if (curSize > growThreshold) {
+    if (curSize > growThreshold && capacity < MAXIMUM_CAPACITY) {
       growTable()
     }
   }
@@ -206,12 +215,8 @@ class AppendOnlyMap[K, V](initialCapacity: Int = 64)
 
   /** Double the table's size and re-hash everything */
   protected def growTable() {
-    val newCapacity = capacity * 2
-    if (newCapacity >= (1 << 30)) {
-      // We can't make the table this big because we want an array of 2x
-      // that size for our data, but array sizes are at most Int.MaxValue
-      throw new Exception("Can't make capacity bigger than 2^29 elements")
-    }
+    // capacity < MAXIMUM_CAPACITY (2 ^ 29) so capacity * 2 won't overflow
+    val newCapacity = (capacity * 2).min(MAXIMUM_CAPACITY)
     val newData = new Array[AnyRef](2 * newCapacity)
     val newMask = newCapacity - 1
     // Insert all our old values into the new array. Note that because our old keys are
@@ -292,3 +297,7 @@ class AppendOnlyMap[K, V](initialCapacity: Int = 64)
    */
   def atGrowThreshold: Boolean = curSize == growThreshold
 }
+
+private object AppendOnlyMap {
+  val MAXIMUM_CAPACITY = (1 << 29)
+}

core/src/main/scala/org/apache/spark/util/collection/PartitionedPairBuffer.scala

@@ -25,11 +25,16 @@ import org.apache.spark.util.collection.WritablePartitionedPairCollection._
 /**
  * Append-only buffer of key-value pairs, each with a corresponding partition ID, that keeps track
  * of its estimated size in bytes.
+ *
+ * The buffer can support up to `1073741823 (2 ^ 30 - 1)` elements.
  */
 private[spark] class PartitionedPairBuffer[K, V](initialCapacity: Int = 64)
   extends WritablePartitionedPairCollection[K, V] with SizeTracker
 {
-  require(initialCapacity <= (1 << 29), "Can't make capacity bigger than 2^29 elements")
+  import PartitionedPairBuffer._
+
+  require(initialCapacity <= MAXIMUM_CAPACITY,
+    s"Can't make capacity bigger than ${MAXIMUM_CAPACITY} elements")
   require(initialCapacity >= 1, "Invalid initial capacity")
 
   // Basic growable array data structure. We use a single array of AnyRef to hold both the keys
@@ -51,11 +56,15 @@ private[spark] class PartitionedPairBuffer[K, V](initialCapacity: Int = 64)
 
   /** Double the size of the array because we've reached capacity */
   private def growArray(): Unit = {
-    if (capacity == (1 << 29)) {
-      // Doubling the capacity would create an array bigger than Int.MaxValue, so don't
-      throw new Exception("Can't grow buffer beyond 2^29 elements")
+    if (capacity >= MAXIMUM_CAPACITY) {
+      throw new IllegalStateException(s"Can't insert more than ${MAXIMUM_CAPACITY} elements")
     }
-    val newCapacity = capacity * 2
+    val newCapacity =
+      if (capacity * 2 < 0 || capacity * 2 > MAXIMUM_CAPACITY) { // Overflow
+        MAXIMUM_CAPACITY
+      } else {
+        capacity * 2
+      }
     val newArray = new Array[AnyRef](2 * newCapacity)
     System.arraycopy(data, 0, newArray, 0, 2 * capacity)
     data = newArray
@@ -86,3 +95,7 @@ private[spark] class PartitionedPairBuffer[K, V](initialCapacity: Int = 64)
     }
   }
 }
+
+private object PartitionedPairBuffer {
+  val MAXIMUM_CAPACITY = Int.MaxValue / 2 // 2 ^ 30 - 1
+}

core/src/main/scala/org/apache/spark/util/collection/PartitionedSerializedPairBuffer.scala

@@ -48,6 +48,8 @@ import org.apache.spark.util.collection.PartitionedSerializedPairBuffer._
  *   |         keyStart         | keyValLen  | partitionId |
  *   +-------------+------------+------------+-------------+
  *
+ * The buffer can support up to `536870911 (2 ^ 29 - 1)` records.
+ *
  * @param metaInitialRecords The initial number of entries in the metadata buffer.
  * @param kvBlockSize The size of each byte buffer in the ChainedBuffer used to store the records.
  * @param serializerInstance the serializer used for serializing inserted records.
@@ -63,6 +65,8 @@ private[spark] class PartitionedSerializedPairBuffer[K, V](
       " Java-serialized objects.")
   }
 
+  require(metaInitialRecords <= MAXIMUM_RECORDS,
+    s"Can't make capacity bigger than ${MAXIMUM_RECORDS} records")
   private var metaBuffer = IntBuffer.allocate(metaInitialRecords * RECORD_SIZE)
 
   private val kvBuffer: ChainedBuffer = new ChainedBuffer(kvBlockSize)
@@ -89,11 +93,17 @@ private[spark] class PartitionedSerializedPairBuffer[K, V](
 
   /** Double the size of the array because we've reached capacity */
   private def growMetaBuffer(): Unit = {
-    if (metaBuffer.capacity.toLong * 2 > Int.MaxValue) {
-      // Doubling the capacity would create an array bigger than Int.MaxValue, so don't
-      throw new Exception(s"Can't grow buffer beyond ${Int.MaxValue} bytes")
+    if (metaBuffer.capacity >= MAXIMUM_META_BUFFER_CAPACITY) {
+      throw new IllegalStateException(s"Can't insert more than ${MAXIMUM_RECORDS} records")
     }
-    val newMetaBuffer = IntBuffer.allocate(metaBuffer.capacity * 2)
+    val newCapacity =
+      if (metaBuffer.capacity * 2 < 0 || metaBuffer.capacity * 2 > MAXIMUM_META_BUFFER_CAPACITY) {
+        // Overflow
+        MAXIMUM_META_BUFFER_CAPACITY
+      } else {
+        metaBuffer.capacity * 2
+      }
+    val newMetaBuffer = IntBuffer.allocate(newCapacity)
     newMetaBuffer.put(metaBuffer.array)
     metaBuffer = newMetaBuffer
   }
@@ -247,12 +257,15 @@ private[spark] class SerializedSortDataFormat extends SortDataFormat[Int, IntBuf
   }
 }
 
-private[spark] object PartitionedSerializedPairBuffer {
+private object PartitionedSerializedPairBuffer {
   val KEY_START = 0 // keyStart, a long, gets split across two ints
   val KEY_VAL_LEN = 2
   val PARTITION = 3
   val RECORD_SIZE = PARTITION + 1 // num ints of metadata
 
+  val MAXIMUM_RECORDS = Int.MaxValue / RECORD_SIZE // (2 ^ 29) - 1
+  val MAXIMUM_META_BUFFER_CAPACITY = MAXIMUM_RECORDS * RECORD_SIZE // (2 ^ 31) - 4
+
   def getKeyStartPos(metaBuffer: IntBuffer, metaBufferPos: Int): Long = {
     val lower32 = metaBuffer.get(metaBufferPos + KEY_START)
     val upper32 = metaBuffer.get(metaBufferPos + KEY_START + 1)