https://programmersought.com/article/248957019/ https://github.com/vbabak/docker-mysql-master-slave Log mysql queries in database:https://tableplus.com/blog/2018/10/how-to-show-queries-log-in-mysql.html https://github.com/alexanderfefelov/docker-mysql-replication Mysql operations: DDL, DML, DCL, TCL

https://www.marcobehler.com/guides/spring-transaction-management-transactional-in-depth Note: 1. Avoid switching data source(like master slave) within a transaction. 2. https://www.changchao.me/?p=782

FeatureActiveMQActiveMQ ArtemisHiveMQJoramMQMosquittoRabbitMQVerneMQOpen sourceApache 2.0Apache 2.0CommercialLGPL, CommercialEPL/EDLMPL 1.1Apache 2.0Commercial supportYESYESHiveMQScalAgentTIBCOPivotalOctavo Labs AGDocker containerrmohr/activemqvromero/activemq-artemishivemq/hivemq3NOeclipse-mosquittorabbitmq:3erlio/docker-vernemqWindows supportYESYESYESYESYESYESNOMQTT version3.13.x3.x, 5.03.x3.1.1, 5.03.1.13.x, 5.0AMQP version11NA0.9.1, 1.0NA0.8, 0.9.x, 1.0NAAMQP interoperabilityNONONANONAPartial (see note 1)NAMQTT over WebSocketYESYESYESYESYESYESYESRetain flagYESYESYESYESYESPartial (see note 2)YESLast will and testamentYESYESYESYESYESYESYESPersistent SessionYESYESYESYESYESYESYESQoS Level 1YESYESYESYESYESYESYESQoS Level 2YESYESYESYESYESNOYESShared subscriptionsNONOYESNONONOYESBridgingNONOYESYESYESNOYESListener topic isolationYESYESClusteringYESYESYESYESNOYESYESREST Management APIYESYESYESYESNOYESYESManagement CLIYESYESYESYESNOYESYESLatest version5.15 (see note 3)2.7.0 (see note 3)45.161.6.23.7.131.7.1GitHub likes1.4K0.5KNANA2.4K5.4K1.7KPerformance comparison:http://acro-engineer.hatenablog.com/entry/2015/12/09/120500Cross Version … Continue reading MQTT Broker Comparison →

PrometheusGraphiteGrafanaWhat it isFully integrated time series DBMS and monitoring systemTime series data logging and graphing toolVisualize and dashboard editing toolWhat it doesScraping, storing, querying, graphing, and alerting based on time series data, also provides API endpoints for the data it holdsStores numeric time series data and provides graphs of that dataVisualize and dashboard editing toolVisualization … Continue reading Monitoring Tool comparison →

https://stackoverflow.com/questions/32437550/whats-the-difference-between-instant-and-localdatetime SHA is a family of “Secure Hash Algorithms” is not encryption , it is a hash function. SHA functions take a large document or value and compute a “digest” (also called “hash”) of the input. Please note this is a one-way process. You can’t retrieve the document from the Hash AES( Advanced Encryption Standard) is symmetric … Continue reading Application Security(encryption) →

Features SQL NoSql 1. Predefined Schema requiredYesNo (dynamic schema)2. ACID propertyYesNo (eventual consistency), work on CAP3. Scalabilityvertically scalablehorizontal scalable4. Replication Master slave architecture Yes5. AvailablitySlave can take over in case of master failureHighly AvailableRelational DBNon-relational ordistributed database system best suited for complex queriesnot so good for complex queries6. High transactional based applicationGoodNot Good Sharding: While sharding … Continue reading Sql vs NoSql Trade off →

How to handle concurrency in mysql : https://blog.gojekengineering.com/on-concurrency-control-in-databases-1e34c95d396e Indexing in Mysql: https://www.youtube.com/watch?v=aZjYr87r1b8

https://www.digitalocean.com/community/tutorials/how-to-back-up-and-restore-your-redis-data-on-ubuntu-14-04 Redis : Spring data redis with spring boot http://qnimate.com/overview-of-redis-architecture/ Redis vs memcached https://www.linkedin.com/pulse/memcached-vs-redis-which-one-pick-ranjeet-vimal/ https://github.com/TechPrimers/spring-redis-example https://www.youtube.com/watch?v=eYfopvusG_s

What is IOT ? https://1sheeld.com/iot-understanding-concepts/ Communication Protocol in IOT https://1sheeld.com/mqtt-protocol/

Opps Design Clarify the requirements: Make sure you understand the expectations of the interviewer. Ask clarifying questions if at all necessary — the interviewer will not mind, and will likely appreciate it. For example, “are you looking for me to demonstrate the structure of a solution, or to fully implement it?” Doing this here will take about 5–10 seconds, … Continue reading System Design(Opps, HLD) →