Programming VIP

After restarting Ali's entOS 7 server, there was an error restarting MySQL Starting mysqld (via systemctl): Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details. [FAILED] Follow t ...

Problems caused by missing XGBoost values and their depth analysis Author: Li Zhaojun, August 15, 2019 Article Links 3,969 words 8 minutes reading 1. Background The XGBoost model, as a "killer" in machine learning, is widely used in ...

1.1. Array 1.1.1. Fixed-length and variable-length arrays (1) Definition format of fixed-length array: val arr=new ArrayT (2) Variable-length array definition format: val arr = ArrayBuffer[T]() Note the need for a guide: import scala. collection. mutable. Array Buffer package cn.itcast.scala import scala.collection.mutable.ArrayBuffer object ...

Chapter 4 IDEA Environmental Applications The spark shell only uses a lot when testing and validating our programs. In production environments, programs are usually written in the IDE, then packaged into jar packages and submitted to the cluster. The most common use is to create a Maven project that uses Maven to manage the dependencies of j ...

Task submission process Summary The start-up process of Spark's Master and Worker are expounded. The next step is the Executor process on Worker. This article continues to analyze the whole process of Executor startup and task submission. Spark-submit It is Spark-submit that submits a task to the cluster Start its main class by starting the s ...

I. Dependency of RDD RDD dependencies fall into two categories: wide dependencies and narrow dependencies. We can think of it as follows: (1) Narrow dependencies: The partition of each parent RDD is used by at most one partition of the child RDD. (2) Wide dependency: Each parent RDD partition is used by multiple child RDD partitions. Narrow ...

When we do file upload, if the file is too large, it may cause the request to time out.Therefore, when you encounter the need to upload large files, you need to upload files in pieces.At the same time, if the file is too large, how to continue the breakpoint when the network is not good?You also need to record the current upload file and make a ...

DAGScheduler--stage partition and creation and stage submission In this article, I will start with the operation of a spark job and connect all the steps involved in the process of spark operation, including the division of DAG graph, the creation of task set, resource allocation, task serialization, task distribution to executor s, task execut ...

Tokenizer (Word segmentation device Introduction to the algorithm: Tokenization divides text into separate individuals (usually words). RegexTokenizer provides more partitioning options based on regular expressions. By default, the parameter "pattern" is a delimiter for dividing text. Or you can specify the parameter "g ...

Overview of dubbo cluster The entry point of dubbo cluster function is in ReferenceConfig.createProxy method and Protocol.refer method. In the ReferenceConfig.createProxy method, if a user specifies multiple provider URLs or registry url s, multiple Invokers are created, then the Invokers are encapsulated in Static Directory, and then the stati ...