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preface: Will MySQL restrict login when there are too many failures to connect to the database? How should the database server deal with violent cracking? This article introduces the connection control plug-in in MySQL. Let's learn the role of this plug-in. 1. Introduction to connection_control plug-in MySQL server contains a plug-in library ...

Catalogue of series articles Related articles: Jetpack: Room super detailed use pit guide! Jetpack:Room+kotlin collaboration? Transaction problem analysis, detailed explanation of withTransaction API Jetpack:Room use error FAQ Jetpack:Room is optimized with LiveData/Flow, and Room+Flow uses principle analysis. Introduction to Room upg ...

Tip: the following is the main content of this article. The following cases can be used for reference 1, Introduction 1.1 what are the existing data storage methods? ① Java programs store data (variables, objects, arrays, collections), which are stored in memory and belong to transient state storage. ② File stores data, which is ...

Chapter 1 basic concepts of Impala 1.1 what is Impala Cloudera provides interactive SQL query function with high performance and low latency for HDFS and HBase data. Based on Hive, it uses memory computing, takes into account data warehouse, and has the advantages of real-time, batch processing, multi concurrency and so on. It is the prefer ...

1, What is a transaction          Transaction refers to a program execution unit that accesses and updates various data in the database. MySQL transactions are mainly used to process data with large amount of operations and high complexity.          (1) . four features (ACID): ...

Persistence Redis supports two persistence mechanisms: RDB(Redis DataBase) and AOF(Append Only File). The persistence function effectively avoids the problem of data loss caused by process exit. Data recovery can be realized by using the previously persistent file when restarting next time. (redis data is stored in memory. In case of sudden do ...

1, Overview Web crawler, also known as Web spider or Web robot, is mainly used to crawl the content of the target website. Distinguish web crawlers in terms of function: data acquisitiondata processingData storage For the above three parts, the basic work framework flow is shown as follows: 2, Principle Function: Download Web p ...

Comparison of several batch insertion efficiencies of [MyBatis] There are three main methods for batch data processing: Execute a single insert statement repeatedlyforeach   Splicing   sqlBatch processing 1, Preliminary preparation Based on Spring Boot  +  Mysql, and lombok is used to omit get/set. See pom.xml for details ...

Problems encountered in development Processing scheme of enumeration type Scheme 1: synchronize the set value by using the key value method 1. Define a new field to store the field description corresponding to the enumeration value Here, quarter is the enumeration value of the corresponding database field @ApiModelProperty(value = "Quarter ...

Overall user shopping What are pv (total visits), average daily visits, uv (total number of users), the number of users with purchase behavior, the shopping situation of users and the repurchase rate? User behavior transformation funnel How about the conversion rate of click Add shopping cart purchase links? What is the abandonment rate of s ...