• Learning records of mongodb master class (day 18)


    Eighteenth days The chapter to be learned today is “21 transaction development: read operation transaction II”. Continue with yesterday’s topic. Yesterday, we talked about where to read the readpreference, and today, we talked about what kind of data readconcert to read. What is readconcert? After the specified node is selected by readpreference, readconcert determines which […]

  • DBA notes – database, table, master-slave, read-write separation


    Preface In the previous blog “spring boot practice and thinking”, I mentioned the separation of master-slave and read-write when comparing the application scenarios of ORM framework with different specifications. This essay will make a more in-depth discussion on this and the sub database and sub table. 1. informal discussion Before I get to the point, […]

  • Learning records of mongodb master class (day 19)


    Nineteenth days The chapter to be learned today is 22 transaction development: multi document transaction, which mainly deals with multi document transaction management. Explain Mongodb started to fully support multi document transactions in 4.2 The principle of using transactions should be: don’t use them as much as possible. By properly designing the document model, we […]

  • MySQL data part (1) simple data modification and transaction use by stored procedure


    1. If required, add Beijing currency manually to the member, and add the allocation log to return whether the modification is successful CREATE DEFINER=`jszapi`@`%` PROCEDURE `p_allot_user_coin`(IN `_member_id` int,IN `_coin` int,OUT `_res` tinyint) BEGIN Declare error int default 0; whether there is SQL error Declare timestamp int; ා current timestamp Declare memberspidcount int default 0; ා […]

  • Pursuit of the ultimate database transaction / analysis hybrid processing system delivery challenge (1)


    Pursue the ultimate database Wobbly database pendulum Technology decision-making in IT industry is like a pendulum swinging back and forth.About ten years ago, new network companies began to collect more data than ever before. They urgently needed to upgrade the expansion performance and processing performance of database systems to a new level. At that time, […]

  • TiDB RC3 Release


    On June 16, tidb officially released version RC3. This version has done a lot of work on MySQL compatibility, SQL optimizer, system stability and performance. In terms of performance, the load balancing scheduling strategy and process are optimized. In terms of function, the authority management function is further improved. Users can control data access authority […]

  • Redis learning note 1 – data structure


    Redis is an efficient NoSQL database, which uses key value to save data and is generally used as a high-speed distributed cache. Redis key design skills Redis, as a cache, can quickly find the required data through the key, which is generally used as the cache of the database. Therefore, the key design of redis […]

  • About exit and Badi enhanced discovery


    Find exit: Method 1: Step 1: input tcode (for example, ME21N) through SE30, execute execute execute, and create a purchase order in the foreground. Click the times tab to find the sap program at the beginning of exit.     Step 2: these functions are an exit provided by tcode. You can query the modsap […]

  • 1z0-062 question bank analysis 2


    Title:Examine the parameters for a database instance: NAME TYPE VALUE ——————————– ————– ————— temp_undo_enabled boolean TRUE undo_management string AUTO undo_retention integer 900 undo_tablespace string UNDOTBSl Your database has three undo tablespaces and the default undo tablespace is not autoextensible. Resumable space allocation is not enabled for any sessions in the database instance. What is the […]

  • An example of optimistic lock and pessimistic lock


    Imagine that you’re going to a restaurant right away, but you’re not sure if the table will be full before you go, and you don’t want to line up. At this time, you will have two choices. If you are an optimistic person, the inner play may be “take care of him, go and say […]

  • SAP s4hana tr transfer operation


    SAP s4hana tr transfer operation Transaction code: STMs? Import,   Select the request, click the funnel button,   Enter the TR to be transmitted (multiple possible), and enter,   Click the request number, press F9,   And then transmit,     Click the “yes” button, the system starts to transmit,   November 24, 2019 in […]