• Get up! It turns out that this is the correct way to implement multithreading


    Java memory modelGet up! It turns out that this is the correct way to implement multithreadingGet up! It turns out that this is the correct way to implement multithreadingthread synchronizationThe thread synchronization mechanism is a set of data access mechanisms suitable for coordinating threads, which can ensure thread safety The thread synchronization mechanism provided by […]

  • Design idea of data warehouse DWS layer — review before construction


    Significance of DWS layer:adoptIndex systemAnalyze and integrate common, reusableDerived indicators, reduce double calculation from (DWD, dim) = > (ads) Build index system:Atomic indicator = business process + measure + aggregation logic Derived indicators=Atomic indicator + statistical cycle + business limit + statistical granularityDerived indicators = integration of multiple derived indicators (proportion, ratio, etc.) Use Excel […]

  • Map type: support for dynamic fields in Clickhouse


    Background introduction In the interactive analysis scenario, in addition to fixed fields, there are also some requirements for dynamic fields. For example, in a game scenario, you need to dynamically store the play duration of each game. In this scenario, we want to store the information of fixed fields and dynamic fields in a table […]

  • MySQL lock learning notes!


    According to lock granularity:Row lock, page lock and table lockThe number of locks at each level is limited, because locks will occupy memory space, and the size of lock space is limited. When the number of locks at a certain level exceeds the threshold of this level, lock upgrading will be carried out. Lock upgrade […]

  • Microservice splitting


    Pain points of monomer architecture The number of database connections has become the bottleneck of application server expansionDatabase connection is an important kind of resources. The connection process is not only time-consuming, but also the number of clients is limited. The monomer architecture increases the cost of R & D and inhibits the improvement of […]

  • (2) Superset 1.3 chart – time series table


    (2) Superset 1.3 chart – time series table This series of articles is based on superset version 1.3.0. Version 1.3.0 currently supports 59 charts of distribution, trend, geography and other types. The updated chart of version 1.3 has some new changes, and there has been no very detailed chart tutorial before. And at present, the […]

  • Chat lock and classification of MySQL learning


    For read, under the RR level mvcc, when a transaction is started, a readview will be generated, and then the qualified historical version will be found through the readview. This version is built by the undo log. When the readview is generated, a snapshot is actually generated, so the select query at this time is […]

  • The extension of monitor supports the timeout lock of string


    The use of monitor can prevent the lock from taking too long, and the corresponding timeout can be set to control the expected code. The reasonable use of timeout can contribute to the robustness of the program. However, for different concurrent programs, we may need different granularity at some time, resulting in a problem that […]

  • 1.1.2 corihua


    Corihua:When a function has multiple parameters, pass some parameters to call it first (these parameters will never change in the future)Then return a new function to receive the remaining parameters and return the result.At first, I learned C language and facial process programming. Later, I came into contact with facial object programming of C + […]

  • If you want to do a good job in microservicing, you should manage this core object well


    Before the text begins, let’s take a look at a daily life scene, coffee vending machine:    In the first row, there are four options: American, latte, mocha and white coffee; The second row, in ml, represents the amount of coffee produced; The third row, whether sugar is added; Fourth row, whether to add milk. […]

  • Some thoughts on the division of micro services


    Our company has implemented the micro service architecture for many years, and I have been in contact with the development for some time. Just recently, I took the time to turn over the book “micro service design” and had the idea of writing this article. Although the description in the article is not very universal, […]

  • MySQL concurrent processing


    Concurrent processing When multiple connections modify records, ensure data consistency and integrity Why use concurrency control Suppose there are commodity records in our database, and now there are two users logging in. Suppose a user wants to delete a record with ID 22 and a user wants to read a record with ID 22, what […]