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Spark Core of Apache Spark
- Python Automation and Machine Learning for ICs -
- An Online Book: Python Automation and Machine Learning for ICs by Yougui Liao -
Python Automation and Machine Learning for ICs                                                           http://www.globalsino.com/ICs/        


Chapter/Index: Introduction | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Appendix

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Spark Core is the foundational component of Apache Spark. Spark Core provides the fundamental functionality of Spark, including the capabilities required to perform basic operations like task scheduling, memory management, fault recovery, interacting with storage systems, and more. Some key aspects of Spark Core are:

  • Resilient Distributed Datasets (RDDs):
    • Spark Core is built around the concept of RDDs, which are fault-tolerant collections of elements that can be operated on in parallel across a cluster of computers. RDDs are the primary data abstraction in Spark, allowing users to perform computations on large datasets that are distributed across many nodes without needing to worry about distribution and fault tolerance.
  • Distributed Task Dispatching:
    • Spark Core includes a scheduler that distributes tasks across the cluster. This scheduler is responsible for breaking down the application into stages of tasks and scheduling these tasks on the cluster nodes.
  • Memory Management:
    • One of the key features that distinguish Spark from other big data frameworks like Hadoop is its in-memory computing capabilities, which allow it to perform many operations up to 100 times faster than Hadoop MapReduce. Spark Core manages the memory used by RDDs and can spill data to disk if there isn’t enough RAM available on the cluster.
  • Fault Tolerance:
    • Through the abstraction of RDDs, Spark Core provides a built-in fault tolerance mechanism by reconstructing lost data automatically if a node fails. This is achieved through lineage information of RDDs, which allows Spark to rebuild lost data by retracing the steps used to create the data.
  • Integration with Storage Systems:
    • Spark Core can interface with various storage systems, such as HDFS (Hadoop Distributed File System), NoSQL databases (like Cassandra), and cloud storage systems (like Amazon S3). This makes it a versatile tool for big data processing across different data ecosystems.
  • Parallel Processing:
    • Spark achieves parallel processing through the division of data into partitions that can be processed concurrently across multiple nodes in a Spark cluster. Each node processes a subset of the data independently but in parallel with the other nodes, which greatly speeds up processing times for large datasets.
  • Distributed Computing:
    • Spark operates on a cluster of machines, spreading data and computations over many servers. This distribution allows Spark to manage and process data that is too large for a single machine. The distributed nature also helps in improving fault tolerance, as the impact of a single machine's failure can be mitigated.
  • Optimized Resource Management:
    • Spark can run on various cluster managers like Apache Hadoop YARN, Apache Mesos, and its own standalone cluster manager. These managers allocate resources across applications, enabling Spark to make efficient use of hardware and allowing for better scaling and management of cluster resources.
  • Advanced DAG (Directed Acyclic Graph) Execution Engine:
    • Unlike traditional MapReduce, which processes data in rigid steps, Spark's DAG scheduler can optimize workflows by reducing the number of read-write operations to disk. This is essential for complex data processing tasks that require multiple steps and can benefit from in-memory data persistence.
  • Scalability:
    • Spark is designed to scale up from a single server to thousands of machines, each offering local computation and storage. This scalability ensures that Spark can handle increasing amounts of data by simply adding more nodes to the cluster.
  • APIs for Various Languages:
    • Spark Core provides APIs in Scala (its native language), Java, Python, and R, making it accessible to a wide range of users from different programming backgrounds.
Spark Core sets the foundation for higher-level libraries built on top of it, including Spark SQL (for structured data processing), MLlib (for machine learning), GraphX (for graph processing), and Structured Streaming (for stream processing). These libraries leverage the core functionalities provided by Spark Core to offer more specialized data processing capabilities.

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