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mavenpkg:maven/org.apache.spark/spark-unsafe_2.13@3.5.x
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tessl/maven-org-apache-spark--spark-unsafe_2-13

tessl install tessl/maven-org-apache-spark--spark-unsafe_2-13@3.5.0

Low-level unsafe operations and optimized data structures for Apache Spark's internal memory management and performance-critical operations.

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Apache Spark Unsafe

Low-level unsafe operations and optimized data structures for Apache Spark's internal memory management and performance-critical operations. This module provides direct memory access capabilities, UTF-8 string processing, hash algorithms, and specialized array implementations designed for maximum performance in memory-constrained environments.

Package Information

  • Package Name: org.apache.spark:spark-unsafe_2.13
  • Package Type: Maven
  • Language: Java
  • Installation: 
    <dependency>
  <groupId>org.apache.spark</groupId>
  <artifactId>spark-unsafe_2.13</artifactId>
  <version>3.5.6</version>
</dependency>

Core Imports

import org.apache.spark.unsafe.Platform;
import org.apache.spark.unsafe.types.UTF8String;
import org.apache.spark.unsafe.memory.MemoryAllocator;
import org.apache.spark.unsafe.memory.MemoryBlock;
import org.apache.spark.unsafe.hash.Murmur3_x86_32;

For array operations:

import org.apache.spark.unsafe.array.LongArray;
import org.apache.spark.unsafe.array.ByteArrayMethods;

Basic Usage

import org.apache.spark.unsafe.Platform;
import org.apache.spark.unsafe.types.UTF8String;
import org.apache.spark.unsafe.memory.MemoryAllocator;

// Direct memory allocation
MemoryAllocator allocator = MemoryAllocator.UNSAFE;
MemoryBlock block = allocator.allocate(1024);

// UTF-8 string operations
UTF8String str1 = UTF8String.fromString("Hello");
UTF8String str2 = UTF8String.fromString(" World");
UTF8String result = UTF8String.concat(str1, str2);

// Platform memory operations
long address = Platform.allocateMemory(64);
Platform.putLong(null, address, 12345L);
long value = Platform.getLong(null, address);
Platform.freeMemory(address);

// Hash calculation
Murmur3_x86_32 hasher = new Murmur3_x86_32(42);
int hash = hasher.hashLong(12345L);

Architecture

The unsafe module is organized into focused capabilities:

  • Platform Operations: Core unsafe memory access and platform-specific utilities
  • Memory Management: Abstract allocators for both heap and off-heap memory with debug capabilities
  • Data Types: Optimized UTF-8 strings, byte arrays, and calendar intervals
  • Array Operations: High-performance array implementations and manipulation utilities
  • Hash Functions: Fast hash algorithms for data processing
  • Bitset Operations: Efficient bitset manipulation for columnar data

Capabilities

Platform Operations

Core platform utilities for unsafe memory operations, direct memory access, and JVM intrinsics that bypass standard Java safety mechanisms for maximum performance.

public static int getInt(Object object, long offset);
public static void putInt(Object object, long offset, int value);
public static long allocateMemory(long size);
public static void freeMemory(long address);
public static void copyMemory(Object src, long srcOffset, Object dst, long dstOffset, long length);

Platform Operations

Memory Management

Abstract memory allocators supporting both heap and off-heap memory allocation with pooling, debug capabilities, and memory block abstractions for TaskMemoryManager integration.

public interface MemoryAllocator {
    MemoryBlock allocate(long size) throws OutOfMemoryError;
    void free(MemoryBlock memory);
}

public class MemoryBlock extends MemoryLocation {
    public long size();
    public void fill(byte value);
}

Memory Management

UTF-8 String Processing

High-performance UTF-8 encoded string implementation with extensive string manipulation capabilities, optimized for internal Spark operations and zero-copy scenarios.

public final class UTF8String implements Comparable<UTF8String>, Externalizable {
    public static UTF8String fromString(String str);
    public static UTF8String concat(UTF8String... inputs);
    public UTF8String substring(int start, int until);
    public boolean contains(UTF8String substring);
    public String toString();
}

UTF-8 String Processing

Array Operations

Optimized array implementations and manipulation utilities including long arrays supporting both on-heap and off-heap memory, and byte array operations with pattern matching.

public final class LongArray {
    public LongArray(MemoryBlock memory);
    public long get(int index);
    public void set(int index, long value);
}

public static boolean arrayEquals(Object leftBase, long leftOffset, Object rightBase, long rightOffset, long length);

Array Operations

Hash Functions

High-performance hash function implementations including 32-bit Murmur3 hasher and Hive-compatible hashing for data compatibility across systems.

public final class Murmur3_x86_32 {
    public Murmur3_x86_32(int seed);
    public int hashInt(int input);
    public int hashLong(long input);
    public int hashUnsafeWords(Object base, long offset, int lengthInBytes);
}

Hash Functions

Data Types and Utilities

Specialized data types including calendar intervals, byte array utilities, bitset operations, and date/time constants for temporal calculations.

public final class CalendarInterval implements Serializable {
    public CalendarInterval(int months, int days, long microseconds);
    public final int months;
    public final int days;
    public final long microseconds;
}

Data Types and Utilities

BitSet Operations

Efficient bitset manipulation utilities for working with fixed-size uncompressed bitsets in memory, designed for columnar data processing and efficient bit-level operations.

public static void set(Object baseObject, long baseOffset, int index);
public static void unset(Object baseObject, long baseOffset, int index);
public static boolean isSet(Object baseObject, long baseOffset, int index);
public static boolean anySet(Object baseObject, long baseOffset, long bitSetWidthInWords);
public static int nextSetBit(Object baseObject, long baseOffset, int fromIndex, int bitsetSizeInWords);

BitSet Operations

Key-Value Iterator

Abstract iterator interface for traversing key-value pairs in Spark's unsafe operations with proper resource management and type safety.

public abstract class KVIterator<K, V> {
    public abstract boolean next() throws IOException;
    public abstract K getKey();
    public abstract V getValue();
    public abstract void close();
}

Key-Value Iterator

Byte Array Utilities

High-performance utilities for byte array operations including memory copying, binary comparison, substring extraction, concatenation, and padding operations.

public static void writeToMemory(byte[] src, Object target, long targetOffset);
public static long getPrefix(byte[] bytes);
public static int compareBinary(byte[] leftBase, byte[] rightBase);
public static byte[] subStringSQL(byte[] bytes, int pos, int len);
public static byte[] concat(byte[]... inputs);
public static byte[] lpad(byte[] bytes, int len, byte[] pad);
public static byte[] rpad(byte[] bytes, int len, byte[] pad);

Byte Array Utilities