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1. MySQL 4. Elasticsearch docker run -d --name=es -p 9200:9200 -p 9300:9300 -e discovery.type=single-node -e ES_JAVA_OPTS="-Xms256m -Xmx512m" -v /es/config/elasticsearch.yml:/usr/share/elasticsearch/config/elasticsearch.yml -v /es/data:/usr/share/elasticsearch/data -v /es/plugins:/usr/share/elasticsearch/plugins ela ...

Redis cluster addresses storage limitations by distributing data across multiple master-slave node groups. Unlike sentinel mode, where all nodes store complete datasets, cluster mode partitions data to reduce individual node pressure. Data Partitioning Strategies Hash Modulo Approach This method applies a hash function to keys and uses modulo o ...

Microservices Architecture Stack Modern distributed systems leverage Spring Cloud Alibaba ecosystem combined with containerized deployement. Core infrastructure components include Nginx for edge traffic management, Spring Cloud Gateway for centralized authentication and routing, Nacos for service discovery and dynamic configuration, Sentinel fo ...

Cache Penetration Cache penetration occurs when a large number of requests target data that exists neither in the cache nor in the database. For example, if users repeatedly request non-existent order numbers like -1, these requests bypass the cache entirely and hit the database directly. This scenario can be exploited maliciously to overwhelm ...

Redis Cache and Database Consistency Caching improves performance and reduces database load, but introduces potential inconsistencies between cached data and the database. Inconsistent data leads to stale reads from the cache. Non-Concurrency Scenarios Update Cache First, Then Database If cache udpate succeeds but database update fails, the cac ...

Redis Sentinel is a system designed to help manage Redis instances, providing high availability through monitoring, notification, and automatic failover. It oversees master and replica instances, promoting a replica to master if the current master fails. This article explains the core concepts of Redis Sentinel and demonstrates how to integrate ...

Prerequisites for Building Redis from Source Before running make test, ensure TCL 8.5 or later is installed: wget http://downloads.sourceforge.net/tcl/tcl8.6.1-src.tar.gz tar xzvf tcl8.6.1-src.tar.gz -C /usr/local/ cd /usr/local/tcl8.6.1/unix/ ./configure make make install Install the GCC compiler: yum install gcc -y Building Redis with syste ...

In modern microservice architectures, Redis is widely used for caching, distributed locking, session storage, and rate limiting. However, the way you interact with Redis differs significantly between a traditional Servlet‑based service (blocking) and a WebFlux‑based gateway (non‑blocking). This guide explains both approaches and provides ready‑ ...

Redis uses eviction policies to manage memory when the maxmemory limit is reached. These policies determine which keys to remove to free up space for new data. Eviction Policies 1. noeviction (default): When memory usage reaches maxmemory, Redis does not evict any existing data. Instead, it returns an error for write requests. This means the ca ...

RedisSpider Overview RedisSpider extends Scrapy's base Spider class to enable distributed crawling. Instead of using a static start_urls list, this spider reads URLs from a Redis queue. Key Differences from Standard Spider The main modifications involve imports, inheritance, and replacing the static URL list with a Redis key: from scrapy_redis. ...