• Advantages, disadvantages and application scenarios of NoSQL such as mongodb, HBase and redis


    Four categories of NoSQL The position of NoSQL database in the whole database field is self-evident. In the era of big data, although RDBMS is excellent, RDBMS is gradually unable to cope with many database processing tasks in the face of the rapidly growing data scale and increasingly complex data model. At this time, NoSQL […]

  • JavaScript — memory management and garbage collection


    catalogue JavaScript memory management Why does memory need to be managed? Memory management concepts Memory management in JavaScript JavaScript memory life cycle JavaScript garbage collection JavaScript garbage collection concept Reference and accessibility examples of JavaScript What are reachable objects? What are garbage collection objects? Understand garbage collection mechanism – GC GC algorithm commonly used by […]

  • Clickhouse series – fanwai – zero copy


    This article will explain to the reader in detail the underlying details of 4K for each read when unordered storage is mentioned in Chapter 3. The appendix in Chapter 3 has explained to the readers that “this reason is that when the operating system reads the disk, according to the principle of data locality, it […]

  • Create a set of APM monitoring system with the most complete client functions


    APM is the abbreviation of application performance monitoring, which monitors and manages the performance and availability of software applications. Application performance management is very important for the continuous and stable operation of an application. So this article talks about how to accurately monitor and report data from the perspective of IOS app performance management App […]

  • Source code | data type for financial scenario: numeric


    Senior Database Kernel R & D of Gao riyao Graduated from Huazhong University of science and technology, likes to study the mainstream database architecture and source code, and has long been engaged in the research and development of distributed database kernel. Once participated in the development of cirrodata kernel of distributed MPP database (Dongfang Guoxin), […]

  • Write OS kernel from scratch – BIOS boot to real mode


    Series catalog Preface preparation BIOS boot to real mode GDT and protection mode On virtual memory Load and enter the kernel Display and print Global descriptor table GDT Interrupt processing Virtual memory perfection Implement heap and malloc First kernel thread Multithread switching Lock and multithreading synchronization Enter user status Process implementation system call Simple file […]

  • Front end memory monitoring – using performance tools


    catalogue Why should memory management be monitored?? Performance tool usage process Memory problem Phenomenon and essence of memory problems Criteria for defining memory problems Several ways to monitor memory Browser Task Manager Timeline sequence diagram record Heap snapshot lookup separates DOM (memory leak can be observed) How many states does DOM exist? example How to […]

  • An analysis of unmanaged memory leak in an API of. Net


    1: Background 1. Tell a story At the end of July, a friend found me on Wx and said that his program memory occupied 8g, while the hosting only occupied 1.5g. He asked where the rest of the memory went? The screenshot is as follows: From the help content, this friend is really very polite. […]

  • 20210322-20210326 technical weekly report


    preface The main technical content this week is to share the basic knowledge of JVM and some production accident cases JVM First ask a question: in the company, what are the parameters of the JVM of the project you are responsible for? For example, the size of the heap, maxheapsize, the size of the new […]

  • Heavy release | detailed explanation of “SQL intelligent diagnosis” function of new generation cloud native data warehouse analyticdb


    Introduction: analyticdb for MySQL provides users with efficient, real-time, feature rich and intelligent “SQL intelligent diagnosis” and “SQL intelligent tuning” functions, provides users with ideas, directions and specific methods for SQL performance tuning, reduces users’ use costs and improves users’ efficiency in using ADB. SQL is a simple and easy-to-use business logic expression language, but […]

  • Husband, how big is your Java object


    When writing java code, in most cases, we pay less attention to how big a Java object is (how much memory it occupies), and more attention to business and logic. However, we don’t know that a large amount of memory is wasted invisibly. How big is a Java object? To accurately calculate the memory occupied […]

  • 7.7 dock stack deployment WordPress


    Docker-compose.yml related fields ENTRYPOINT_ Mode includes VIP mode and dnssr mode. VIP mode is to use multiple containers for unified virtual IP. Dnsrr is to use real IP and then poll IP. VIP mode is used by default One mode is global and the other is replicated. The former does not support horizontal expansion, and […]