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The article walks through MySQL’s query execution flow, shows how to profile slow statements, explains index‑related pitfalls, connection‑pool limits, and InnoDB buffer‑pool sizing, and provides concrete commands and examples to diagnose and speed up sluggish queries.
The article explains why modifying a HashMap—by removing, adding, or putting entries—while iterating with a Java foreach loop causes a ConcurrentModificationException, demonstrates the underlying bytecode transformation, and shows how to safely perform such operations using an Iterator.
The article analyzes why Kafka messages are duplicated on both producer and consumer sides, explains at‑most‑once, at‑least‑once, and exactly‑once delivery semantics, and walks through three concrete remedies—idempotent producers, transactions, and consumer‑side deduplication—backed by configuration details, code samples, and practical deployment steps.
This article walks through eleven practical methods—such as adding proper indexes, optimizing SQL, parallelizing remote calls, eliminating duplicate queries, using async processing, shrinking transaction scope, refining lock granularity, applying pagination, leveraging caching layers, and employing sharding and monitoring tools—to dramatically improve backend interface performance.
The article shows how using Collectors.toMap can trigger IllegalStateException for duplicate keys and NullPointerException for null values, and demonstrates proper merge functions, Optional handling, and a plain‑for‑loop alternative to safely convert a List of objects into a Map.
This article walks through setting up MinIO, installing it via Docker on CentOS 7, configuring Spring Boot, and implementing chunked, instant‑resume, and resumable uploads for large files, complete with code examples, Docker commands, and troubleshooting tips.
This article explains the fundamental concepts of service registries, examines CAP theory and consensus protocols, and provides a detailed analysis of Zookeeper, Eureka, Nacos, Consul, and Etcd—including their architectures, features, trade‑offs, and practical guidance for selecting the most suitable registry for a given environment.
This article walks through a complete gray‑release solution built on Spring Cloud, Nacos as the service registry, and a custom load‑balancer, detailing the architecture, code implementation, configuration, and step‑by‑step deployment to demonstrate traffic splitting and version routing.
This article presents ten essential advanced MySQL concepts—including CTEs, recursive CTEs, temporary functions, CASE‑WHEN pivots, EXCEPT vs NOT IN, self‑joins, ranking window functions, delta calculations, running totals, and date‑time manipulation—each explained with clear examples and practical SQL snippets.
The article walks through real interview scenarios where MySQL or Java processes consume 900% CPU, detailing step‑by‑step diagnosis with top, processlist, jstack, and concrete remediation such as adding indexes, using caches, fixing busy loops, and tuning memory.
