Hive SQL

1. Primitive types

• Types are associated with the columns in the tables. The following Primitive types are supported:
• Integers
  • TINYINT—1 byte integer
  • SMALLINT—2 byte integer
  • INT—4 byte integer
  • BIGINT—8 byte integer
    Read more »

MCS locks and qspinlocks

Cited from (https://lwn.net/Articles/590243/)

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By Jonathan Corbet
March 11, 2014

Impressive amounts of effort have gone into optimizing the kernel’s low-level locking mechanisms over the years, but that does not mean that there is no room for improving their performance further. Some work that will be in the 3.14 3.15 kernel, with more likely to come later, has the potential to speed up kernel locking considerably, especially in situations where there are significant amounts of contention.

Hadoop - 1. Introduction

What’s Hadoop?

1. Hadoop is a distributed system infrastructure developed by the Apache Foundation
2. Mainly solve, the storage of massive data and the analysis and calculation of massive data
3. Broadly speaking, Hadoop usually refers to a broader concept - the Hadoop ecosystem, including HBASE, HIVE, etc

847. Shortest Path Visiting All Nodes

Description：

You have an undirected, connected graph of n nodes labeled from 0 to n - 1. You are given an array graph where graph[i] is a list of all the nodes connected with node i by an edge.

Return the length of the shortest path that visits every node. You may start and stop at any node, you may revisit nodes multiple times, and you may reuse edges.