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Summary Pg_stat_states is an extension plug-in of PostgreSQL database, which is used to collect the running information of SQL in the database, such as the total execution time of SQL, the number of calls, the hit rate of shared memory and so on. Used to monitor the performance of database is an important expansion module of database performanc ...

Summary:This blog is the tenth in the "Java Second Kill System Practical Series Articles". In this blog, we will adopt RabbitMQ's death letter queue to deal with the situation that "user's death letter queue generates orders successfully but fails to pay late", so we can see the strength of RabbitMQ's death letter queue in t ...

1. Create test case library tables Welcome to the MariaDB monitor. Commands end with ; or \g.Your MariaDB connection id is 11Server version: 10.2.26-MariaDB-log MariaDB Server Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> ...

Principle of Single Responsibility A class and a method should have only one responsibility. For example: public function getFullNameAttribute() { if (auth()->user() && auth()->user()->hasRole('client') && auth()->user()->isVerified()) { return 'Mr. ' . $this->first_name . ' ' . $this->middle_nam ...

After the data warehouse is built, users can write Hive SQL statements to access them and analyze the data. In actual production, which statistical indicators are needed are usually proposed by the relevant departments of data demand, and new statistical requirements will continue to emerge. The following are some typical indicators in website ...

Links to the original text: https://blog.csdn.net/topdandan/article/details/81436141 1. Configure elastic Search in spring boot 1.1 Introducing related jar packages into engineering 1.1.1 Add the required jar package to build.gradle I ...

There are two types of data sources: Ordinary Data Source: Data Source Driven by Database Connection pools include connection pools with database drivers and common third-party connection pools such as DBCP and C3P0.     Data Source with Database Driver 1 //from properties File Loading Data Source Configuration 2 Properties ...

Preface: The previous articles introduce the use of DML and DDL statements. This article will mainly describe the commonly used query grammar. In fact, MySQL official website gives many sample databases for your practical query. Below we take the most commonly used employee sample database as the standard, and introduce in detail their commonly ...

Section I: Overview of JDBC Section II: JDBC Connecting to Database Section III: Use Statement interface to add, delete and change operations Section IV: Use PreparedStatement interface to add, delete and change Section 5: Resultset result set Sectio ...

In addition to transferring data safely between goroutine s, after reading Concurrency in Go, I lament that channel has so many patterns to use. In my personal learning, I summarize the following common patterns. pipeline concept We take reptiles as an example. Generally, reptiles are divided into the following steps: Grab Page - > Parse Pag ...