• Classic examples of database and information system


    Classic examples of database and information system @Langyuan qihan Updated on: January 3, 2020 This is the final version. The classic examples are from the course “database and information system”. They are only for academic exchange and final review. If there is any mistake, please point out the source when reprinting! 1、 Basic concept verification […]

  • Tidb source reading series (XVI) insert statement details


    In the previous article “tidb source reading series (IV) insert statement Overview”, we have introduced the general process of insert statement. Why do I need to write a separate article for insert? Because in tidb, simply inserting a piece of data is the simplest and most commonly used case; what’s more complicated is to set […]

  • Spring spring AOP principle, handwritten spring transaction framework


    1、 Spring core knowledge Spring is an open source framework. Spring is a lightweight java development framework that emerged in 2003. It is derived from some concepts and prototypes that rod Johnson elaborated in his book expert one on one J2EE development and design. It is created to solve the complexity of enterprise application development. […]

  • Tpc-b test: how much better is Greenplum 6 than 5?


    About pgbench: Pgbench is a simple program to run benchmark on PostgreSQL. It may run the same sequence of SQL commands over and over in a concurrent database session and calculate the average transaction rate (transactions per second). By default, pgbench tests a tpc-b-based but more relaxed scenario involving five select, update, and insert commands […]

  • MySQL Foundation (05): logical architecture diagram and details of InnoDB storage engine


    Source code: GitHub, click here, gitee, click here 1、 MySQL logical architecture 1. Logic architecture diagram Based on the following logical architecture diagram, you can be familiar with the collaborative working relationship between various MySQL architecture components. The classic C / S architecture style is client / server mode. 2. Hierarchical description Client connection Generally, […]

  • Linux time synchronization tips


    Ntpdate system time, hwlock hardware time1. Judge whether the current time is accurate[[email protected] ~]# dateTuesday, March 3, 2020 10:13:02 CST 2. Check if ntpdate is installed[[email protected] ~]# ntpdate-bash: ntpdate: command not found 3. Check whether the network is connected, such as Alibaba cloud’s time server. If you can’t connect to the external network, choose the […]

  • Four transaction isolation levels of MySQL


    Concurrency of transactions 1. Dirty read: transaction a reads the updated data of transaction B, and then B rolls back the operation, so the data read by a is dirty data 2. Non repeatable reading: transaction a reads the same data multiple times, and transaction B updates and commits the data in the process of […]

  • Tidb source reading series (19) tikv client (2)


    In the previous article, we introduced several specific problems that need to be solved by tikv client in the process of data reading and writing. In this paper, we will continue to introduce two main modules in tikv client: copitters which are responsible for processing distributed computing and twophasecommitters which are submitted in two phases. […]

  • Oracle database small knowledge point arrangement


    –Database stores data   –What are the main databases on the market   –Oracle MySQL –IBM DB2 Finance –Microsoft SQL Server   –These are relational databases.   –NoSQL is not only SQL, but also typical mongodb   —————– —————————————- –What are the classifications of database languages — ************************************** /*** 1. Data definition language (DDL), create, […]

  • Redis NoSQL introduction and overview


    Brief history and definition of NoSQL NoSQLThe term was first used in1998Year oldCarlo StrozziNamed on his lightweight, open source relational database, but the database does not provide a standardSQLInterface;stay2009InEric EvansTo talk about distributed open source database, yesNoSQLMainly non relational, distributed, not providing relationalatomicity(A),consistency(C),isolation(I),durability(D)NamelyACIDCharacteristics;Then2009Held in Atlanta inno:sqlThe symposium was a milestone. The slogan at that time […]

  • On MySQL transaction and acid


    Recently, I have built my personal blog, link here: tobe’s raving words, articles will be updated in blog and official account. The so-called transaction is to maintain the integrity of the database by ensuring that batch operations are either fully executed or not executed at all. Take a rotten Street example: a transfers 1000 yuan […]

  • Understanding spring transaction manager


    Why transaction manager is needed Without a transaction manager, our program might look like this: Connection connection = acquireConnection(); try{ int updated = connection.prepareStatement().executeUpdate(); connection.commit(); }catch (Exception e){ rollback(connection); }finally { releaseConnection(connection); } It’s also possible to have such “elegant affairs”: execute(new TxCallback() { @Override public Object doInTx(Connection var1) { //do something… return null; } […]