• Redis learning notes (11) server


    Redis server is responsible for establishing network communication with multiple clients, processing command requests sent by clients, saving data generated by client executing commands in database, and maintaining the operation of server itself through resource management.   Command request process (take set command as an example)   1. The client sends a command to the […]

  • Redis study notes (XIII) copy (2)


    In the last article, we wrote a simple application of redis replication function. Let’s take a look at the implementation process of redis replication function. The following is basically the theoretical part, boring, but I hope you can have a look, after all, knowledge is not all interestedStand loneliness, stand temptation, can keep prosperous ~~Implementation […]

  • Redis redis basic types and Java operation


    1 Introduction to redis Redis (promote dictionary server) is an open source, network-based, memory based, persistent key value pair storage system written in ANSI C. At present, the most popular key value pair storage system. It is often used as database, cache and message queue. Advantages of redis: The efficiency of memory based database is […]

  • The mongodb service has hung up and the restart log reports an error out of memory


    1. Problem Description: Today, all of a sudden, my PHP colleague told me that the pre released Mongo was dead. I went up to see the log and it showed that: reason: My colleague said that he built an index, and then Mongo hung up. When mongodb rebuilt the index, it consumed all the memory, […]

  • Installing redis in Windows


      1、 Download address   2、 Install redis 1. Open the download address, you can see that there are installation packages and compressed packages to choose from. I download the installation package here   2. Open the installation package, install and click next   3. Check the consent agreement and proceed to the next […]

  • Use of Yii redis list


      Redis list allows users to push or pop up elements from both ends of the sequence, get list elements, and perform various common list operations. Here are some common list processing commands, and their use in Yii. RPUSH RPUSH:RPUSH key-name value [value …]Push one or more values to the right end (tail) of the […]

  • Manually install yii2 redis extension


      Originally, I wanted to download the yii2 redis extension through composer. It’s too slow. I haven’t installed it in the morning. Please install it manually. Here’s a record. 1、 Download address   2、 Use 1. After decompression, it is renamed yii2 redis, and the downloaded extension is placed in thevendor/yiisoftUnder the directory   […]

  • Redis learning notes (18) cluster (2)


    Replication and failover The nodes in redis cluster are divided into master node and slave node. The master node is used to process slots, while the slave node is used to copy a master node. When the copied master node is offline, it will continue to process command requests instead of the offline master node. […]

  • Mongodb — Security Authentication


    Brief introduction of user and role permissions of mongodb By default,MongoDBWhen an instance starts and runs, the user access control is not enabled. That is to say, the local server of the instance can connect to the instance at will for various operations,MongoDBNo user authentication is performed on the connected client. To enable user access […]

  • Redis – expiration policy and memory elimination mechanism


    Expiration Policies 1、 Scene application Problem: for example, you can only store 5g data in redis, but if you write 10g, 5g data will be deleted. Have you ever thought about how to delete it? Also, your data has set the expiration time, but when the time comes, the memory utilization is still relatively high. […]

  • Install redis under windows and start it automatically


    1. Download address:, the latest versionRedis 5.0.10 for Windows 2. Run the redis command as follows:redis-server.exe 3. Add redis to the service of windows (service and loglevel are two before -) and boot up automatically redis-server –service-install –loglevel verbose 4. Common redis service commands. Uninstall service:redis-server –service-uninstall Open service:redis-server –service-start Out of Service:redis-server […]

  • Mongodb import and export and database backup


    ——————-Mongodb data import and export——————- 1、 Data export: mongoexport 1. Concept: Mongoexport tool in mongodb can export a collection to a file in JSON format or CSV format. The exported data items can be specified by parameters, or the data can be exported according to the specified conditions. 2. Grammar:         mongoexport […]