HBase Hlog原理总结归纳

万字HBase详解带你畅游大数据的海豚湾 本文深入到HBase的起源开始分析,从0开始带你畅游大数据的海豚湾!让你轻松掌握HBase的原理,架构设计,存储设计,优点及适用场景。 阅读详情

HBase Hlog原理总结归纳

1. Hlog概述

  1. 按照此前另外一篇博客所述,Hlog其实就是为了保存内存缓存数据现场而建立的一套机制Hbase内部机制
  2. Hlog也叫做WAL文件,全名是write ahead log。
  3. 故名思意,就是在数据写入到memory store之前,先把信息写入到这个wal日志文件中。

2. Hlog简介

  1. Write Ahead Log (WAL)提供了一种高并发、持久化的日志保存与回放机制.这一点和hdfs的checkpoint机制很类似,都是通过追加形式的磁盘日志文件来还原内存数据现场,防止内存数据丢失
  2. 采用磁盘文件追加可以达到很高的磁盘IO性能,具体看我另外一篇博文 磁盘顺序读写
  3. 将现场以日志形式记录下来,其实有很多应用如mysql的binlog就是如此。
  4. 每一个业务数据的写入操作(PUT / DELETE)执行前,都会记账在WAL中。,用来做灾难恢复只用,Hlog记录数据的所有变更,一旦数据修改,就可以从log中进行恢复
  5. 每个Region Server维护一个Hlog,而不是每个Region一个
  1. 不同region(来自不同table)的日志会混在一起,这样做的目的是不断追加单个 文件相对于同时写多个文件而言,可以减少磁盘寻址次数,因此可以提高对table的写性能。
  2. 带来的麻烦是,如果一台region server下线,为了恢复其上的region,需要将region server上的lo
HBase跨集群数据复制:WAL日志同步原理、配置与实战指南 在大数据架构中,数据的高可用与灾备能力是企业系统稳定运行的关键。HBase作为广泛使用的分布式列式存储,其跨集群复制技术为解决机房容灾、读写分离、数据汇聚等场景提供了基础方案。该机制本质上是基于WAL(Write-Ahead Log)日志的异步重放过程:主集群将写入操作记录到日志后,由后台线程推送至备集群并重新执行,从而实现最终一致性。理解Replication的WAL同步原理、Peer配置、复制队列状态及延迟监控,是运维人员保障数据链路可靠性的核心技能。同时,结合Snapshot快照与日志追赶策略,可高效 阅读详情

相关推荐

实战指南:基于华为Ascend NPU的大模型W8A8量化调优与精度提升

本文提供了一份基于华为Ascend NPU进行大模型W8A8量化的实战调优指南。详细介绍了从环境搭建、使用msmodelslim框架进行基础量化,到通过离群值抑制、校准集优化和量化回退等关键技术提升精度的全流程。旨在帮助开发者在华为NPU硬件上实现模型推理的显著加速,同时有效控制精度损失。

weixin_29227425的博客 271

极空间NAS零基础部署Wiki.js:Docker+PostgreSQL全流程避坑指南

本文提供了一份在极空间NAS上从零部署Wiki.js私有知识库的详细指南。通过Docker容器化技术,结合PostgreSQL数据库,手把手讲解环境准备、核心组件配置、性能优化及安全加固等全流程,并特别针对极空间平台特性提供了避坑要点,帮助用户打造安全、高效、自主可控的知识管理系统。

3a9bq4r8t2y的博客 486

反激变压器设计学习笔记

反激变压器匝比感量设计

m0_55419117的博客 5262

【硬件】LT3763中文手册

1)精确控制输入和输出电流;2) 3000:1真彩色PWM™调光;3) ±1.5%电压调节精度;4) ±6%电流调节精度;5)6V至60 V输入电压范围;6)宽输出范围最高可达55V;7)<2µA关断电流;8)用于负载电流热控制的控制引脚;9)输入和输出电流监控和限制;10)开路、短路和C/10故障检测;11)适用于LED应用的PWM驱动器输出;12)热增强型28引脚FE封装。

qq_39200110的博客 489

置顶必读(1) |《YOLOv8实战:从入门到深度优化》专栏导读,带你一文了解本专栏!

🏆 本文收录于 《YOLOv8实战:从入门到深度优化》 专栏,该专栏专注于分享我在YOLOv8目标检测模型中的实战经验,涵盖从入门基础到深度优化的全方位解决方案。无论你是计算机视觉的新手,还是具有多年深度学习经验的专家,本专栏都将为你提供高效、可复现的技术方案,助你掌握YOLOv8的核心技术,提升目标检测性能,突破瓶颈,优化模型,并加速项目开发🚀!

**My Coding Family** 14万+

DataX对接数据如何在ODS加密脱敏数据(插件开发)

datax对接mysql数据,对姓名只保留姓,名变成**。对这种简单的脱敏,可以不用修改datax源码,直接在配置文件上实现。

大模型大数据攻城狮的专栏 994

YOLOv8 智能交通违章检测 - 压线/越线行驶检测详解

本文提出了一种基于YOLOv8的智能交通违章检测方案,重点解决车辆压线/越线行驶的识别问题。系统采用多技术融合方案:YOLOv8检测车辆、ByteTrack跟踪轨迹、传统或深度学习方法识别车道线,并通过几何计算判断车辆是否违规跨越实线。文章详细介绍了技术难点(如车道线分类、透视变形处理)、判定流程、系统架构和核心代码实现,包括车道线检测、违章逻辑判断和可视化模块。同时指出了现有方案的局限性,建议通过引入逆透视变换和专用车道线分割模型来提升准确率。该纯视觉方案具有低成本、易部署的特点,适用于智能交通监控场景。

u010117029的博客 175

【DRAM存储器三十五】LPDDR4介绍--主要技术特性之VREF training,为什么要做VREF training?

详述DDR4、LPDDR4需要做vref training的原因和训练过程

highman110的博客 2915

Probability and Statistics - 4th edition

Probability and Statistics - 4th edition

蓝牙模块HM-10手册

蓝牙模块HM-10手册,该手册对蓝牙模块HM-10进行了详细的介绍和使用方法以及一些AT指令。

霍尼韦尔SoftMaster使用说明

霍尼韦尔SoftMaster使用说明

深度学习工具包 DeepLearningToolbox

深度学习工具包Deprecation notice.-----This toolbox is outdated and no longer maintained.There are much better tools available for deep learning than this toolbox, e.g. [Theano](http://deeplearning.net/software/theano/), [torch](http://torch.ch/) or [tensorflow](http://www.tensorflow.org/)I would suggest you use one of the tools mentioned above rather than use this toolbox.Best, Rasmus.DeepLearnToolbox================A Matlab toolbox for Deep Learning.Deep Learning is a new subfield of machine learning that focuses on learning deep hierarchical models of data.It is inspired by the human brain's apparent deep (layered, hierarchical) architecture.A good overview of the theory of Deep Learning theory is[Learning Deep Architectures for AI](http://www.iro.umontreal.ca/~bengioy/papers/ftml_book.pdf)For a more informal introduction, see the following videos by Geoffrey Hinton and Andrew Ng.* [The Next Generation of Neural Networks](http://www.youtube.com/watch?v=AyzOUbkUf3M) (Hinton, 2007)* [Recent Developments in Deep Learning](http://www.youtube.com/watch?v=VdIURAu1-aU) (Hinton, 2010)* [Unsupervised Feature Learning and Deep Learning](http://www.youtube.com/watch?v=ZmNOAtZIgIk) (Ng, 2011)If you use this toolbox in your research please cite [Prediction as a candidate for learning deep hierarchical models of data](http://www2.imm.dtu.dk/pubdb/views/publication_details.php?id=6284)```@MASTERSTHESIS\{IMM2012-06284, author = "R. B. Palm", title = "Prediction as a candidate for learning deep hierarchical models of data", year = "2012",}```Contact: rasmusbergpalm at gmail dot comDirectories included in the toolbox-----------------------------------`NN/` - A library for Feedforward Backpropagation Neural Networks`CNN/` - A library for Convolutional Neural Networks`DBN/` - A library for Deep Belief Networks`SAE/` - A library for Stacked Auto-Encoders`CAE/` - A library for Convolutional Auto-Encoders`util/` - Utility functions used by the libraries`data/` - Data used by the examples`tests/` - unit tests to verify toolbox is workingFor references on each library check REFS.mdSetup-----1. Download.2. addpath(genpath('DeepLearnToolbox'));Example: Deep Belief Network---------------------```matlabfunction test_example_DBNload mnist_uint8;train_x = double(train_x) / 255;test_x = double(test_x) / 255;train_y = double(train_y);test_y = double(test_y);%% ex1 train a 100 hidden unit RBM and visualize its weightsrand('state',0)dbn.sizes = [100];opts.numepochs = 1;opts.batchsize = 100;opts.momentum = 0;opts.alpha = 1;dbn = dbnsetup(dbn, train_x, opts);dbn = dbntrain(dbn, train_x, opts);figure; visualize(dbn.rbm{1}.W'); % Visualize the RBM weights%% ex2 train a 100-100 hidden unit DBN and use its weights to initialize a NNrand('state',0)%train dbndbn.sizes = [100 100];opts.numepochs = 1;opts.batchsize = 100;opts.momentum = 0;opts.alpha = 1;dbn = dbnsetup(dbn, train_x, opts);dbn = dbntrain(dbn, train_x, opts);%unfold dbn to nnnn = dbnunfoldtonn(dbn, 10);nn.activation_function = 'sigm';%train nnopts.numepochs = 1;opts.batchsize = 100;nn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.10, 'Too big error');```Example: Stacked Auto-Encoders---------------------```matlabfunction test_example_SAEload mnist_uint8;train_x = double(train_x)/255;test_x = double(test_x)/255;train_y = double(train_y);test_y = double(test_y);%% ex1 train a 100 hidden unit SDAE and use it to initialize a FFNN% Setup and train a stacked denoising autoencoder (SDAE)rand('state',0)sae = saesetup([784 100]);sae.ae{1}.activation_function = 'sigm';sae.ae{1}.learningRate = 1;sae.ae{1}.inputZeroMaskedFraction = 0.5;opts.numepochs = 1;opts.batchsize = 100;sae = saetrain(sae, train_x, opts);visualize(sae.ae{1}.W{1}(:,2:end)')% Use the SDAE to initialize a FFNNnn = nnsetup([784 100 10]);nn.activation_function = 'sigm';nn.learningRate = 1;nn.W{1} = sae.ae{1}.W{1};% Train the FFNNopts.numepochs = 1;opts.batchsize = 100;nn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.16, 'Too big error');```Example: Convolutional Neural Nets---------------------```matlabfunction test_example_CNNload mnist_uint8;train_x = double(reshape(train_x',28,28,60000))/255;test_x = double(reshape(test_x',28,28,10000))/255;train_y = double(train_y');test_y = double(test_y');%% ex1 Train a 6c-2s-12c-2s Convolutional neural network %will run 1 epoch in about 200 second and get around 11% error. %With 100 epochs you'll get around 1.2% errorrand('state',0)cnn.layers = { struct('type', 'i') %input layer struct('type', 'c', 'outputmaps', 6, 'kernelsize', 5) %convolution layer struct('type', 's', 'scale', 2) %sub sampling layer struct('type', 'c', 'outputmaps', 12, 'kernelsize', 5) %convolution layer struct('type', 's', 'scale', 2) %subsampling layer};cnn = cnnsetup(cnn, train_x, train_y);opts.alpha = 1;opts.batchsize = 50;opts.numepochs = 1;cnn = cnntrain(cnn, train_x, train_y, opts);[er, bad] = cnntest(cnn, test_x, test_y);%plot mean squared errorfigure; plot(cnn.rL);assert(er<0.12, 'Too big error');```Example: Neural Networks---------------------```matlabfunction test_example_NNload mnist_uint8;train_x = double(train_x) / 255;test_x = double(test_x) / 255;train_y = double(train_y);test_y = double(test_y);% normalize[train_x, mu, sigma] = zscore(train_x);test_x = normalize(test_x, mu, sigma);%% ex1 vanilla neural netrand('state',0)nn = nnsetup([784 100 10]);opts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samples[nn, L] = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.08, 'Too big error');%% ex2 neural net with L2 weight decayrand('state',0)nn = nnsetup([784 100 10]);nn.weightPenaltyL2 = 1e-4; % L2 weight decayopts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex3 neural net with dropoutrand('state',0)nn = nnsetup([784 100 10]);nn.dropoutFraction = 0.5; % Dropout fraction opts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex4 neural net with sigmoid activation functionrand('state',0)nn = nnsetup([784 100 10]);nn.activation_function = 'sigm'; % Sigmoid activation functionnn.learningRate = 1; % Sigm require a lower learning rateopts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex5 plotting functionalityrand('state',0)nn = nnsetup([784 20 10]);opts.numepochs = 5; % Number of full sweeps through datann.output = 'softmax'; % use softmax outputopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex6 neural net with sigmoid activation and plotting of validation and training error% split training data into training and validation datavx = train_x(1:10000,:);tx = train_x(10001:end,:);vy = train_y(1:10000,:);ty = train_y(10001:end,:);rand('state',0)nn = nnsetup([784 20 10]); nn.output = 'softmax'; % use softmax outputopts.numepochs = 5; % Number of full sweeps through dataopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, tx, ty, opts, vx, vy); % nntrain takes validation set as last two arguments (optionally)[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');```[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/rasmusbergpalm/deeplearntoolbox/trend.png)](https://bitdeli.com/free "Bitdeli Badge")

上一篇: HBase StoreFile原理总结
下一篇: HBase负载均衡总结归纳
闻香识代码
博客等级 码龄12年 314粉丝 223原创
评论
成就一亿技术人!
拼手气红包6.0元
还能输入1000个字符
 
 条评论被折叠 查看
添加红包

请填写红包祝福语或标题

个

红包个数最小为10个

元

红包金额最低5元

当前余额3.43元 前往充值 >
需支付:10.00元
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付元
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值