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The previous article introduced Execution plan in TiDB , this article will continue to introduce the SQL optimization process in TiDB, and understand the implementation logic of TiDB optimizer from the two stages of logical optimization and physical optimization. 1. SQL optimization process SQL optimization in TiDB is divided into two stage ...

preface: Learn some notes on Redis by yourself 📒 Write it down, and it's convenient for you to look through it Course link: https://coding.imooc.com/class/151.html Book recommendation: Redis development and operation and maintenance First article: https://sleepymonster.cn Here is just an introduction or a search ~ For a specific ...

1, es introduction? 1 es introduction Introduction: es is an open source distributed (full-text) search engine based on Apache lucene. It provides a simple restful API to hide the complexity of Lucene. es database analogy: Relational DBdatabasetablesrowsFields (columns)ElasticsearchIndexes (incices)typesdocumentsfields ES is also a distr ...

1, Background   when we use the database, we will inevitably encounter the situation that the data is deleted by mistake, which may be business operation errors and code bug s; It may also be an operation and maintenance error, etc; However, we can divide all operations into the following categories: Data loss due to DMLData loss due ...

SQLite database storage Write in front SQLite is a lightweight relational database. Its operation speed is very fast and occupies very few resources. It usually only needs a few hundred K of memory, so it is especially suitable for mobile devices. SQLite not only supports the standard SQL syntax, but also follows the ACID transaction of th ...

background Because the new environment is online, data needs to be migrated from the old environment to the new environment. Scheme Research Scheme 1: copy data directory First, observe the directory structure of ClickHouse on the file system (configured in the configuration file / ECT / ClickHouse server / config. XML) ), for ease ...

Mybatis mapping one-on-one //Custom mapping <resultMap type="User" id="userRoleResult"> <result column="roleName" property="userRoleResult"> </resultMap> <select id="getUserList5" resultMap="userRoleResult"> select su.id, su.userCode, su.userName, su.gender, su.phone, sr.roleName FROM ...

background In the previous experience, taos client, RESTful Connector and JDBC-JNI are used. This time, we experience an example closer to the actual application scenario: the integration of TDengine with SpringBoot, MyBatis, MyBatisPlus, etc. Officials have brought their own examples, https://github.com/taosdata/TDengine/tree/develop/tests/e ...

CRUD (add, delete, modify, query) 1 increase There are two ways to add data. 1)save By creating a model class object, execute the save() method of the object and save it to the database. >>> from datetime import date >>> book = BookInfo( btitle='Journey to the West', bpub_date=date(1988,1,1), bread=10, bcomm ...

See the architecture and introduction of tidb TiDB Overall Architecture | PingCAP Docs understands the overall architecture of TiDB.https://docs.pingcap.com/zh/tidb/v4.0/tidb-architecture brief introduction            TiDB yes PingCAP The Open Source Distributed Relational Database, designed and developed independently by the company, is a hy ...