Parallel I/O and Columnar Storage We begin with a high level overview of the system while follow up posts will discuss specific components in more detail. The target audience are software and systems engineers with an interest in databases and distri…

/** Spark SQL源代码分析系列文章*/ 前面讲到了Spark SQL In-Memory Columnar Storage的存储结构是基于列存储的. 那么基于以上存储结构,我们查询cache在jvm内的数据又是怎样查询的,本文将揭示查询In-Memory Data的方式. 一.引子 本例使用hive console里查询cache后的src表. select value from src 当我们将src表cache到了内存后,再次查询src,能够通过analyzed运行计划来观察内部调…

/** Spark SQL源码分析系列文章*/ 前面讲到了Spark SQL In-Memory Columnar Storage的存储结构是基于列存储的. 那么基于以上存储结构,我们查询cache在jvm内的数据又是如何查询的,本文将揭示查询In-Memory Data的方式. 一.引子 本例使用hive console里查询cache后的src表. select value from src 当我们将src表cache到了内存后,再次查询src,可以通过analyzed执行计划来观察内部调用…

/** Spark SQL源码分析系列文章*/ Spark SQL 可以将数据缓存到内存中,我们可以见到的通过调用cache table tableName即可将一张表缓存到内存中,来极大的提高查询效率. 这就涉及到内存中的数据的存储形式,我们知道基于关系型的数据可以存储为基于行存储结构 或 者基于列存储结构,或者基于行和列的混合存储,即Row Based Storage.Column Based Storage. PAX Storage. Spark SQL 的内存数据是如何组织的? Spar…

https://spark.apache.org/sql/ Performance & Scalability Spark SQL includes a cost-based optimizer, columnar storage and code generation to make queries fast. At the same time, it scales to thousands of nodes and multi hour queries using the Spark eng…

A treewalk for splitting a file directory is disclosed for parallel execution of work items over a filesystem. The given work item is assigned to a worker. Thereafter, a request is sent to split the file directory to share a portion of the file direc…

Awesome Big Data A curated list of awesome big data frameworks, resources and other awesomeness. Inspired byawesome-php, awesome-python, awesome-ruby, hadoopecosystemtable & big-data. Your contributions are always welcome! Awesome Big Data Frameworks…

https://github.com/onurakpolat/awesome-bigdata A curated list of awesome big data frameworks, resources and other awesomeness. Inspired by awesome-php, awesome-python, awesome-ruby, hadoopecosystemtable & big-data. Your contributions are always welco…

Short Description: ORC Creation Best Practices with examples and references. Article Synopsis. ORC is a columnar storage format for Hive. This document is to explain how creation of ORC data files can improve read/scan performance when querying the d…

原文链接 Awesome Java A curated list of awesome Java frameworks, libraries and software. Contents Projects Bean Mapping Build Bytecode Manipulation Caching CLI Cluster Management Code Analysis Code Coverage Code Generators Compiler-compiler Configuration…