Tag:Null value

  • What about cache penetration?

    Time:2020-3-25

    In the current Internet architecture, almost every internet project will introduce a caching system, such as redis and memcached. To protect the downstream database and improve the system concurrency. No matter what kind of caching system you use, you may encounterCache penetrationThe problem. Cache penetration refers to the situation that no data is queried in […]

  • New features of es2020

    Time:2020-3-20

    1、 Use the ා – sign to quickly create private variables of a class One of the main purposes of class is to reuse our code into more modules, but we don’t want to expose all the properties and methods. Now, with this new feature, we can easily implement this idea, just add a ා […]

  • Cache penetration, avalanche, hotspot and redis

    Time:2020-3-1

    Recommend this article to you: anti avalanche design of redis architecture: the tactics behind the website’s no downtime (in addition, I recommend last year’s essay as a pre dinner snack — a brief discussion on server cache design) The anti avalanche design of the Redis architecture, which is called “original”, is very well written. It […]

  • Null is your friend, not a mistake

    Time:2020-3-1

    Original author: Roman elizarov Original address: null is your friend, not a mixer Translator: Theory of mind Kotlin Island from Wikimedia by Pavlikhin, CC BY-SA 4.0 I have been programming in the Java language for a long time. I have learned what to pay attention to when writing and maintaining large-scale software (millions of lines […]

  • . net best practices – learning notes

    Time:2020-2-13

    . net best practices ========== ========== ==========Stephen Ritchie(c) Huang Dengqiao, Huang Haoyu, Li Yong[publication] Mechanical Industry Press[edition] January 2014 Edition 1[printing time] first printing in January 2014[price] 69.00 yuan========== ========== ========== (P001) Developers should be skeptical of any practice they call “best practice.”. Developers should choose which “best practices” to adopt based on their specific […]

  • MySQL index notes

    Time:2020-2-5

    MYSQL index 1、 Advantages and disadvantages of index Advantage:   1. By creating a unique index, you can ensure the uniqueness of each row in the database table. 2. It can greatly speed up the query speed, which is the main reason for creating indexes 3. In terms of data reference integrity, it can speed […]

  • Summary of the Use of Oracle Composite Index and Null Index

    Time:2019-6-2

    Yesterday, we discussed a question of SQL optimization in QQ group. The statements are as follows: Select A, min (B) from table group by A; – A, B do not have null constraints, column A has no null value, column B has null value. – There is a composite index IX_TEST (A, B) So manual […]