• How to measure Linux performance and avoid the most typical error: CPU


    In this series, we will discuss Linux performance measurement and how to measure it correctly. Linux performance is a very broad topic, so we will focus on the four main resources that usually improve system performance — CPU, memory, disk storage and network. Now, when we talk about component related performance, many scenarios just need […]

  • test2


    Test2 new to fwq 1. Setting – XMS = – Xmx goes without saying 2. The initial heap memory allocated by the JVM is specified by – XMS, which is 1 / 64 of the physical memory by default; the maximum heap memory allocated by the JVM is specified by – Xmx, which is 1 […]

  • Diagram of the storage allocation strategy of tcapsusdb


    preface There are many ways to save data. The most direct way is to build a data structure in memory to save data. For example, with a list, every time a piece of data is received, a record is appended to the list. This scheme is very simple and has good performance, but the problem […]

  • Introduction of txhdb storage engine


    Introduction of storage engine Database storage engine is the underlying software organization of database. Database management system (DBMS) creates, queries, modifies and deletes data through data engine. Different storage engines provide different storage mechanism, indexing skills, locking level and other functions. Using different storage engines, you can also obtain specific database functions. As the supporting […]

  • 996 is so hard, why go to the Internet factory to experience the good news?


    The words “996”, “overtime” and “sudden death” haunt most people in the IT industry all the time. Why go to the Internet factory to experience the fortune telling? Big companies (Alibaba, Huawei, Tencent, etc.) pay a lot of money though they are 996. Take PDD for example, the undergraduate can give 35K, the master can […]

  • Go memory allocator


    readNotes on the touranddravenessSummary of memory management of go technological processThe user program obtains new memory space from heap through allocator,Reclaim space through collector distributorGo uses free list allocator to allocate memory, and adopts isolation adaptation method Free list allocatorWhen the user program applies for memory, the free list allocator will traverse the free memory […]

  • How to close the worker process gracefully?


    When we explained the nginx command line before, we can see that there are two ways to stop nginxnginx -s quitandnginx -s stopWhere stop means to stop nginx immediately, and quit means to turn off nginx gracefully. The corresponding signal is the same. In addition, the processes of reload and hot upgrade mentioned earlier involve […]

  • The difference and usage of calloc, malloc and realloc functions


    /*The memory size needs to be calculated manually and is not initialized*/ int *p = (int *)malloc(20 * sizeof(int)); /*There is no need to calculate the memory size manually, and it is initialized to 0*/ int *q = (int *)calloc(20, sizeof(int)); /*Dynamic memory expansion / reduction * 1. Successful allocation: *1.1 if the return address […]

  • Implementation of JSP FusionCharts free display chart


    Download address of FusionCharts free: http://www.fusioncharts.com/goodies/fusioncharts-free/ Next, introduce JS into the JSP page Copy codeThe code is as follows: <script type=”text/javascript” src=”FusionChartsFree/JSClass/FusionCharts.js”></script> Then write it Copy codeThe code is as follows: <script type=”text/javascript”>        var chart = new FusionCharts(“FusionChartsFree/Charts/FCF_Column3D.swf”, “column1”, “800”, “600”);        chart.setDataURL(“FusionChartsFree/Gallery/Data/Column3D.xml”);        chart.render(“div1”);</script> The parameters of the second line are as follows: SWF address of […]

  • Druid configuration


    Druiddatasource configuration is compatible with DBCP, but the semantics of individual configurations are different. to configure Default value explain name The significance of configuring this property is that if there are multiple data sources, they can be distinguished by name when monitoring. If there is no configuration, a name will be generated in the format […]

  • Golang connection pool you must understand


    Problem introduction As a golang developer, the online environment has encountered a number of connection explosion problems (MySQL / redis / Kafka, etc.). For this reason, golang, as a resident process, needs to manually close the connection after requesting a third-party service or resource, otherwise the connection will always exist. Most of the time, developers […]

  • Comprehensive analysis of java thread pool


    Java – five thread pools, four denial policies, three blocking queues There are three kinds of blocking queues     BlockingQueue<Runnable> workQueue = null; Workqueue = new arrayblockingqueue < > (5); / / array based FIFO queue, boundedWorkqueue = new linkedblockingqueue < > (); / / linked list based FIFO queue, unboundedWorkqueue = new synchronous queue […]