• [Mr. Zhao Qiang] calculate aggregation using MapReduce in mongodb


    MapReduce can calculate very complex aggregation logic and is very flexible. However, MapReduce is very slow and should not be used in real-time data analysis. MapReduce can be executed in parallel on multiple servers. Each server is only responsible for completing part of the wordload. Finally, the wordload is sent to the master server for […]

  • An analysis of CPU burst height of a web station of an e-commerce trading platform on. Net


    1: Background 1. Tell a story I’ve written several real cases about memory inflation in succession. I’m a little numb. Let’s share one for a changeCPU burst heightSome time ago, a friend found me on Wx and said that he often received an old projectCPU > 90%The alarm information is very embarrassing. Now that you […]

  • Lasso regression analysis based on R language


    Original link:http://tecdat.cn/?p=10997 Simulated false data set  set.seed(0820)  n         <- 50  p         <- 25  beta      <- rep(0,p)  beta\[1:5\] <- 1:5/5  X <- matrix(rnorm(n*p),n,p)  X <- scale(X)  Xb <- X%*%beta  Y <- X%*%beta+rnorm(n)  Y <- Y-mean(Y)  plot(cor(X,Y),xlab=”j”,ylab=”Cor(Y,X_j)”,main=”Sample correlations”,cex=2) Standard least square method  summary(ols) ##  ## Call: ##  ## Residuals: ##      Min       1Q   Median       3Q      Max  ## -2.54540 -0.38971 -0.00738  0.49058  1.90900  ##  ## Coefficients: ##               Estimate Std. Error t value Pr(>|t|)     ## (Intercept) -3.914e-16  1.648e-01   0.000  1.00000     ## X1           6.020e-01  2.097e-01   2.871  0.00841 **  ## X2           5.924e-01  2.013e-01   2.944  0.00709 **  ## X3          -1.106e-01  2.290e-01  -0.483  0.63363     ## X4           1.117e+00  2.058e-01   5.427 1.42e-05 *** ## X5           1.234e+00  2.190e-01   5.633 8.46e-06 *** ## X6          -3.225e-01  2.322e-01  -1.389  0.17755     ## X7          -1.954e-01  2.150e-01  -0.909  0.37231     ## X8           1.466e-01  2.532e-01   0.579  0.56803     ## X9           4.678e-02  2.353e-01   0.199  0.84409     ## X10         -2.779e-01  2.151e-01  -1.292  0.20864     ## X11         -7.308e-02  2.553e-01  -0.286  0.77717     ## X12         -4.424e-02  2.642e-01  -0.167  0.86839     ## X13         -1.078e-01  2.101e-01  -0.513  0.61270     ## X14          3.000e-01  2.263e-01   1.326  0.19743     ## X15          2.396e-01  2.480e-01   0.966  0.34365     ## X16         -1.178e-01  2.285e-01  -0.515  0.61100     ## X17         -2.409e-01  2.280e-01  -1.057  0.30104     ## X18         -3.191e-01  2.396e-01  -1.332  0.19551     ## X19         -1.207e-01  2.372e-01  -0.509  0.61553     ## X20          1.721e-01  2.179e-01   0.790  0.43733     ## X21         -1.677e-02  2.144e-01  -0.078  0.93831     ## X22          3.706e-02  2.145e-01   0.173  0.86426     ## X23          3.233e-02  2.108e-01   0.153  0.87938     […]

  • The production environment encountered a go problem, and the whole group was confused


    Wechat search【Fried fish in my head】Pay attention to this fried fish with fried liver. this paperGitHubGithub.com/eddycjy/blog has been included, including my series of articles, materials and open source go books. Hello, I’m fried fish. Some time ago, when I was frantically writing code, a reader suddenly asked me a question, which made me interested: I’m […]

  • Use of stored procedures (2) conditional statements and circular statements


    Conditional statement part Circular statements: Yes 1.REPEAT Statement until conditional expression executed until the conditional expression is true END REPEAT;** 2.WHILE Conditional expression DO Series of statements END WHILE The difference between the while loop statement and the repeat loop control statement is that the former will not execute the loop body once the conditions are not […]

  • K8s actual combat (IV) | controller deployment


    preface The previous section mentioned that the pod created directly has no self-healing function. The pod created by the controller can be self-healing, so what is the controller. It can be understood that the container is a bare box. Pod packed the box to facilitate k8s mounting. How to mount several pods in k8s at […]

  • Talk about your understanding of BFC?


    Talk to youBFCYour understanding? What is it? Written explanation:BFC (Block Formatting Context)These are in English Block: block can be understood here asBlock-level Box, refers to the standard for block level boxes Formatting context: block level context formatting, which is a rendering area in the page and has a set of rendering rules, which determines how […]

  • Application of dataX in data migration


    Introduction: application of dataX in data migration DataX definition =========== First, briefly introduce what dataX is.DataX is an offline data synchronization tool / platform widely used in Alibaba group. It realizes efficient data synchronization between various heterogeneous data sources, including mysql, Oracle, sqlserver, postgre, HDFS, hive, ads, HBase, tablestore (OTS), maxcompute (ODPs), DRDS, etc. DataX […]

  • Detailed explanation of springboot case


    1.3 springboot case implementation Case requirements: request the method in the controller and respond the return value to the page (1) Build a spring boot project using spring initializr In essence, spring initializr is a web application. It provides a basic project structure and can help us quickly build a basic spring boot project Project […]

  • Push box game in C language! The strongest resolution in the whole network can be learned by the neighbor’s dog!


    I wanted to share the small games I had made for you very early (super simple), but I haven’t had a chance. I have nothing to do today. I’ll serve you a dish. The code is not very difficult. I hope all the friends who read this article can write it by themselves in the […]

  • Algorithm and data structure series (I) – level differentiated understanding of algorithms


    Series articles: Algorithm and data structure series (I) – level differentiated understanding of algorithms Algorithm and data structure series (II) – Basic preparation before implementation Algorithm and data structure series (III) – select sort Algorithm and data structure series (IV) – insertion sorting method – insert sort Algorithm and data structure series (V) – improvement […]

  • R language Lasso regression model variable selection and diabetes development prediction model


    Original link:http://tecdat.cn/?p=22721  Lease absolute shrinkage and selection operator (lasso) performs regularization and variable selection on a given model. Depending on the size of the penalty term, Lasso reduces the less relevant predictors to (possibly) zero. Therefore, it enables us to consider a more concise model. In this set of exercises, we will implement lasso regression […]