• Your parquet should be upgraded: ioexception: totalvaluecount = = 0 problem location trip


    Summary:When using spark SQL for ETL task, an error is reported when reading a table: “ioexception: totalvaluecount = = 0”, but there is no exception when writing the table. This article is shared from Huawei cloud community《Your parquet should be upgraded: ioexception: totalvaluecount = = 0 problem location trip》, original author: wzhfy. 1. Problem description […]

  • PI Ziheng embedded: This paper introduces the multi-channel link mode of i.mxrt timer pit and its application in coremark test engineering


    Hello everyone, I’m ruffian Heng, a serious technical ruffian. What ruffian Heng introduced to you today isi. Multi channel link mode of mxrt timer pit and its application in coremark test。 As early as 2018, when i.mxrt series crossover processors were just launched, ruffian Heng wrote an articleI.mxrt1052 performance measurement (coremark), the article introduces in […]

  • [shutter 1-5] the first item of running shutter – counter


    Create project There are many ways to create a flutter project, and various ide tools also integrate the shortcut of creating a flutter project. Here are three ways: using the command line to create, using Android studio to create, and using vscode to create. Create using the command line After the installation of flutter, we […]

  • Using Redux in react and implementing counter cases


    React + Redux Problems encountered when Redux is not used in recat In react, the data of component communication is one-way. The top-level component can transfer data to the lower level component through props attribute, while the lower level component cannot transfer data to the upper level component. In order to modify the data of […]

  • Analysis of Python garbage collection mechanism


    summary Program refers to the dynamic application of memory space in the process of execution, and these memory spaces are no longer needed as the program runs. At this time, if these spaces are not released, the resident memory will become useless garbage, which leads to memory leakage.Garbage collection mechanism: GC. The existence of garbage […]

  • Application of JMeter counter


    Some common parameterization methods used by JMeter are: CSV Data Set Config User defined variables User parameters Regular /json/bean extractor BeanShell PostProcessor Function assistant [\u csvread, \random, \u time, etc.] Define global variables:User defined variables, user parameters Define random variables:Function assistant [\random] Define the specified constant:CSV data set config, function assistant [\u csvread], regular /json […]

  • Python: drawing progress bar with tqdm module


    In computation intensive iterative computation, we often need to know the current iteration rounds. The most traditional method is to print the rounds of the current iteration counter. Is there a better way? We can use the tqdm module (not built-in in py, which needs to be followed separately) to draw the progress bar on […]

  • Can countdownlatch add await on multiple threads?


    stayCountDownLatchDuring the use of class, a very strange phenomenon is found: CountDownLatch countDownLatch = new CountDownLatch(2); Runnable taskMain = () -> { try { countDownLatch. await(); // Waiting for wakeup } catch (InterruptedException e) { e.printStackTrace(); } System. out. Println (“continue task”); }; Runnable taskMain1 = () -> { try { countDownLatch. await(); // Waiting […]

  • [Java interview] how does the JVM judge that an object can be recycled


    Hi, this is mic. Today, I would like to share an interview question that must be asked by a first-line Internet company. ”How does the JVM determine that an object can be recycled“ About this question, let’s take a look at the answers of ordinary people and experts. average person: Um………. killer: OK, interviewer. In […]

  • Service current limiting


    background Current throttling exists in highly available services.Protection means for high availability, mainly including caching, degradation and current limitingFlow restriction: only the specified events are allowed to enter the system. The exceeding part will be denied service, queued or degraded.Why current limiting is required:1: The service can’t handle the pressure2: The self-protection mechanism adopted due […]

  • JSP counter making


    The counter is a must for general websites. Don’t underestimate it. Whenever the webmaster looks at the rapid growth of the number on the small counter, he feels really good. In the past, we used CGI and ASP to write counters. There are many articles in this field. Here, we will use the popular JSP […]

  • Go basic knowledge sorting (IV)


    Go basic knowledge sorting (IV) The philosophy of go is “do not communicate through shared memory, but share memory through communication”. Channels are the carriers for go to share memory through communication. Common methods of rumtime package runtime. Numgoroutine() // returns the number of coroutines of the current program runtime. Gomaxprocs (0) // get the […]