Antlr
介绍 Antlr 基本概念、特性、工作机制、内部运作流程,以及踩到的一些坑。
Nginx™ [engine x] is an HTTP and reverse proxy server, a mail proxy server, and a generic TCP/UDP proxy server
在 Nginx Archive 下载页面,下载 nginx-1.13.12.tar.gz 安装包
1 | $ yum -y install openssl openssl-devel |
1 | $ tar zxvf nginx-1.13.12.tar.gz |
1 | $ cd /usr/local/nginx/ |
1 | $ ps -ef | grep nginx |
1 | root 107034 1 0 Oct31 ? 00:00:00 nginx: master process sbin/nginx |
Presto™ (PrestoDB™) is an open source distributed SQL query engine for running interactive analytic queries against data sources of all sizes ranging from gigabytes to petabytes.
Presto™ (PrestoSQL™, a.k.a. Trino™) is a high performance, distributed SQL query engine for big data.
负责管理 Worker 和 MetaStore 节点,以及接受客户端查询请求,并进行 SQL 的语法解析(Parser)、执行计划生成与优化(Planner)和查询任务的调度(Scheduler)
负责具体的查询计算和数据读写
负责发现集群的各个节点,用于节点间心跳监控
1 | List(1, 9, 2, 4, 5) span (_ < 3) // (List(1), List(9, 2, 4, 5)) 碰到不符合就结束 |
1 | import scala.collection.{AbstractIterator, mutable} |
InfluxDB™ is a time series database designed to handle high write and query loads. It is an integral component of the TICK stack. InfluxDB is meant to be used as a backing store for any use case involving large amounts of timestamped data, including DevOps monitoring, application metrics, IoT sensor data, and real-time analytics.
类似于传统数据库中的 DataBase 概念
和 OLAP 中广义上的度量概念一致,部分 OLAP 数据库中又称为 Metric
和 OLAP 中广义上的维度概念一致,部分 OLAP 数据库中又称为 TagKV
数值
时间戳
数据点
数据点组成的序列
数据过期策略,即 TTL