Programmer Group

Description: According to the technical feedback, some people mistakenly deleted the online mongodb table data in the morning, the user has feedback to the customer service, now it is necessary to restore the data to the user. The first step is to determine the schema of the database for deleted data 1.1, Single point:If there is a backup, sta ...

background From the perspective of monitoring, Secondary uses about 11GB more physical memory than Primary, For basic memory analysis, you can read this written by another student of the team first Troubleshooting documents， The user is not set to read in the standby database. There is basically no traffic in the Secondary database, only the ...

mongoDB Replica Set Actual Warfare background Features of a mongoDB single server: - Risk of data loss - Single server cannot be highly available Features of the mongoDB replica set: -High Availability Architecture to Prevent Data Loss - Keep multiple replicas synchronized and consistent - The mongodb replica set switches automatically when ...

Simple configuration and database connection of NodeJS build project The main contents are as follows: Load exprss module Create app app Load template processing Set up static file hosting Load database module Blog offline Processing post requests Cookie settings Load exprss module var express = require('express ...

It has been updated to some simple basic types until one day an update operation covering a certain field (this field is an array) was written. There is a problem. There is a problem in the database A little confused. Of course, if we set the type when updating, this problem will not occur. One of the preconditions for this problem is that we a ...

download Choose the appropriate installation package for your system version. This article installs CentOS 7 MongoDB's official website is https://www.mongodb.com/ , you can download the MongoDB program on the official website. The reason why it's a program is that the relevant programs of MongoDB in the downloaded installa ...

Preface Before introducing a technology, it must be clear what problems the technology can solve for the project. Before I understood message queue, I thought that message queue was mainly used to send messages such as SMS and email (asynchronous decoupling), but I found my understanding was wrong on ...

introduce Whether mysql or mongodb, the traditional way to interact with database is to write code according to the API they provide. The APIs they provide are often not easy to understand and hard to remember. If you pass wrong parameters and write a wrong symbol, you need to check the document. The ORM (Object Relational Mapping) framework ...

1. Briefly introduce that scrapy official documents have more code but fewer changes, while the second sends fewer codes but changes more. 1. The first method; the official document method.We can go to settings to copy the document web address into the official document for copy and paste.(Only three modifications are required ...

The front end is not only to render the data on the page, but also to do a lot of things For example, we should do a good job in safety Suppose, a management system, when you log in the system, you do not do security work Other people can add, delete, modify and check your data through your interface. T ...