• Installing and deploying mongodb 4.4 on CentOS 8.2


    catalogue What is mongodb?: Environmental specifications: To install mongodb Yum repository in CentOS 8: Set resource limits for mongodb in CentOS 8: To install the mongodb database on CentOS 8: Create SELinux policy for mongodb on CentOS 8: Create administrator user in mongodb: Enable access control in mongodb server: Configure mongodb service for network access: […]

  • [Mr. Zhao Qiang] index in mongodb (Part 2)


    (4) Type 3 of index: compound index Mongodb supports composite indexes, that is, multiple keys are combined to create indexes. This method is called composite index, or composite index. This method can meet the use of index in multi key value matching query. Secondly, when using a composite index, you can also use the index […]

  • PHP operation redis common commands


    //Connect to the local redis service $redis = new Redis(); $redis->connect(‘’, 6379); $redis->auth(‘123456’); /*********************Key*********************/ //Del key [key…] —– delete one or more given keys $a = $redis->del(array(‘xrj’,’ly’,’fjf’)); //Keys pattern —— find all keys that match the given pattern $b = $redis->keys(‘*’); //Random key —— randomly returns (does not delete) a key from the current database […]

  • What is “hybrid cloud”?


    In this paper, we define the concept of “hybrid cloud”, explain four different cloud deployment models of hybrid cloud, and deeply analyze the industrial trend of hybrid cloud through a series of data and charts. 01 introduction Hybrid cloud is a computing environment that integrates multiple platforms and data centers. Generally speaking, hybrid cloud is […]

  • CentOS 8.2 deploying CouchDB 3.3 database


    CouchDBIs an open source, document oriented NoSQL database. In this article, you will learn how to install Apache CouchDB on CentOS 8. catalogue What is Apache CouchDB? Environmental specifications: Step 1: update CentOS 8 package Step 2: install EPEL Yum repository on CentOS 8 Step 3: install CouchDB Yum repository on CentOS 8 Step 4: […]

  • Redis replication


    catalogue 1、 Replication introduction 2、 Copy configuration 2.1 create replication 2.1.1 command 2.1.2 demonstration 2.2 fracture replication 3.2.1 direct disconnection 3.2.2 switching to another master 3、 Topology 4、 Replication process 5、 Data synchronization principle 5.1 components required by PSYNC command 5.1.1 master slave copy offset 5.1.2 master node copy backlog buffer 5.1.3 master node operation […]

  • Cassandra and kubernetes


    This article will introduce how to integrate Cassandra with distributed applications and manage it with kubernetes. We will also provide many ready-made resources to help you learn quickly.       Cassandra and kubernetes   Are you developing applications on the cloud? Then you must belong to one of these two camps: you are using […]

  • Redis sentry


    catalogue 1、 Basic concepts and architecture 1.1 basic concepts 1.2 architecture 2、 Deployment demo 2.1 deploy master-slave nodes 2.2 deploy sentry nodes 2.3 failover demonstration 3、 Client connection (configuration provider) 3.1 code 3.2 principle 4、 Implementation principle 4.1 three scheduled tasks 4.2 subjective offline and objective offline 4.3 leader sentinel node election 4.4 failover 1、 […]

  • Redis cluster (1)


    catalogue 1、 Introduction to cluster 2、 Redis cluster data partition principle 2.1 hash partition scheme 2.1.1 node redundancy partition 2.1.2 consistent hashing 2.2 redis cluster data partition scheme 3、 Build a cluster 3.1 preparation node 3.2 creating clusters 4、 Principle of node communication 4.1 visit message 4.2 communication node selection 1、 Introduction to cluster Redis […]

  • Redis source code series (1)


    Redis source code series memory management Function prototypesrc/zmalloc.h Function pointer andvoid*Pointer provides a generic mechanism /*stringfication*/ #define __xstr(s) __str(s) #define __str(s) #s /*prototypes*/ void *zmalloc(size_t size); void *zcalloc(size_t size); void *zrealloc(void *ptr, size_t size); void zfree(void *ptr); char *zstrdup(const char *s); size_t zmalloc_used_memory(void); void zmalloc_enable_thread_safeness(void); void zmalloc_set_oom_handler(void (*oom_handler)(size_t)); float zmalloc_get_fragmentation_ratio(size_t rss); size_t zmalloc_get_rss(void); #ifndef HAVE_MALLOC_SIZE […]

  • Analysis of the impact of CPU architecture on redis performance


    catalogue 1、 Mainstream multi core CPU 1.1 multi core CPU cache structure 1.2 impact on redis 2、 NUMA CPU 2.1 UMA (SMP) architecture vs NUMA architecture 2.2 impact on redis This paper mainly analyzes the impact of CPU architecture on the performance of redis based on the architecture and operation mechanism of CPU. 1、 Mainstream […]

  • How to judge whether redis is slowing down


    As an in memory database, redis is fast,So how to judge whether redis is slowing down? What is the standard of slowing downBecause the configuration environment of the machine is different, we can’t simply compare the response time. Redis provides a tool to detect the performance baseline of redis. If it exceeds a certain range […]