Tag:time consuming

  • IOS block solves circular reference


    First, solve the circular reference I Basic controller code: #import “ViewController.h” ///The first two solve circular references typedef void(^CPBlock)(void); ///Used for the third solution to circular references typedef void(^CPParamBlock)(ViewController *); @interface ViewController () ///The first two solve circular references示例 @property(nonatomic, copy) CPBlock block; ///Used for the third solution to circular references示例 @property(nonatomic, copy) CPParamBlock paramBlock; […]

  • [TCP] start with an online problem and explain the TCP semi connection queue and full connection queue in detail


    Starting from an online problem, explain the TCP semi connection queue and full connection queue in detail https://network.51cto.com/article/687595.html https://www.cnblogs.com/sidesky/p/6844228.html https://developer.aliyun.com/article/79972 About parameters such as listenoverflows of netstat https://blog.csdn.net/weixin_34256074/article/details/89079053 About the time-consuming things of TCP connection https://zhuanlan.zhihu.com/p/266540301 What happens when the TCP semi connection queue and full connection queue are full, and how to deal with […]

  • Comparison between easypoi and easyexcel


    Export 100W pieces of data (divided into 100 times, each simulation returns 1W pieces of data, 10 threads are concurrent 3 times, 20 threads are concurrent 2 times) and the memory is controlled at 1g.code: easy-poi: Date start = new Date(); Exportparams params = new exportparams (“big data test”, “test”); Random random=new Random(); Workbook workbook […]

  • Android App startup speed optimization


    Application startup process summary: ① Click to start an app, and the launcher process uses binder IPC to initiate a startactivity request to activitymanagerservice;② After receiving the request, the activitymanagerservice sends a request to create a process to the zygote process;③ The zygote process forks out a new sub process, that is, the app process;④ […]

  • Reflection optimization of mybatis


    This article mainly introduces the related contents of reflection optimization of mybatis. Let’s understand how reflection optimization of mybatis is done and why reflection optimization is needed. It is based on version 3.4.6 Knowledge points What is reflection Why should mybatis be optimized How is mybatis optimized What is reflection When it comes to reflection, […]

  • K8s disk falling log data statistics


    phenomenon After the data collection end collects data, the output system finds that the system data cannot be queried. After troubleshooting, it is found that it is the access problem and governance problem:1. Access problemIf the data needs to be uploaded to the MySQL system, it can’t be processed directly. A datamaster is used in […]

  • Mongodb export scenario query optimization


    introduction Some time ago, I encountered a similar scenario of exporting data. After observation, I found that the speed will be slower and slower. Exporting 1 million data takes 40-60 minutes. From the log observation, I found that the time is also higher and higher. reason From the perspective of code logic, batch export is […]

  • Track the killer who ran out of server CPU


    When we discussed the system call earlier, the conclusion is that it takes 200ns-15us. But what I said today about my experience may give you a better understanding of the real cost of system calls. In this section, you will see a connect system call that takes 2.5ms. Note that milliseconds is equivalent to 2500us! […]

  • Will there be performance problems if there are too many function calls?


    Function overhead confusion In modern development work, I believe that most of the students’ projects are not built from the zero line of code. Each language has its own popular code framework, such as laravel, CodeIgniter, ThinkPHP and so on. Everyone adds their own business code logic on the basis of their own framework to […]

  • Android startup optimization analysis


    There are many performance optimization schemes, but few can be applied to the project When learning layout optimization some time ago, I summarized many layout optimization schemes, but in the end, they can not be applied in the project:[from getting started to giving up] in depth analysis of Android layout optimization Today, as always, without […]

  • Kotlin coprocessor — coroutinescope function


    public suspend fun <R> coroutineScope(block: suspend CoroutineScope.() -> R): R { contract { callsInPlace(block, InvocationKind.EXACTLY_ONCE) } return suspendCoroutineUninterceptedOrReturn { uCont -> val coroutine = ScopeCoroutine(uCont.context, uCont, true) coroutine.startUndispatchedOrReturn(coroutine, block) } } It’s asuspendfunction,Create a new collaboration scopeAnd execute the specified code block within the scope,It does not start the process。 The purpose of its existence […]

  • Project practice of improving primary memory performance


    Except C + +, most modern development languages encapsulate memory management, and ordinary developers have no access to the underlying operation of memory. What’s more, there are more and more excellent open source component applications, such as MySQL and redis, which don’t even need to be developed by everyone. Just use them directly. Some students […]