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Every command issued after it (until `EXEC` or `DISCARD`) is queued on the connection rather than run immediately.",{"id":149,"topic":9,"difficulty":132,"body":150,"options":151,"correct_key":142,"explanation":160},"019f89ea-069e-768e-8e82-7698fb7e18ee","Which command actually executes the commands queued after `MULTI`?",[152,154,156,158],{"key":136,"text":153},"`COMMIT`",{"key":139,"text":155},"`RUN`",{"key":142,"text":157},"`EXEC`",{"key":145,"text":159},"`FLUSH`","`EXEC` executes all commands queued since `MULTI`, atomically, and returns their replies as an array.",{"id":162,"topic":9,"difficulty":132,"body":163,"options":164,"correct_key":136,"explanation":173},"019f89ea-069e-7f39-bc77-a666a419f6fc","What does `DISCARD` do inside an open Redis transaction?",[165,167,169,171],{"key":136,"text":166},"Cancels the transaction and clears the queued commands without running them",{"key":139,"text":168},"Runs every queued command, returns their replies, and then rolls back all resulting changes before closing the transaction",{"key":142,"text":170},"Deletes the key that was being watched",{"key":145,"text":172},"Removes only the last queued command, keeping the rest","`DISCARD` flushes the queued command list and closes the transaction; nothing in it is executed.",{"id":175,"topic":9,"difficulty":176,"body":177,"options":178,"correct_key":145,"explanation":187},"019f89ea-06a2-742a-91d8-2d06718cc20f",2,"What is `WATCH` used for in a Redis transaction?",[179,181,183,185],{"key":136,"text":180},"Logging every command executed inside the transaction to a file",{"key":139,"text":182},"Blocking every other client from reading or writing the watched key until the watching connection commits or disconnects",{"key":142,"text":184},"Periodically refreshing a key's TTL while the transaction is open",{"key":145,"text":186},"Making the following `EXEC` abort if any watched key was modified since the `WATCH`","`WATCH key` implements optimistic locking: if the watched key changes (by any client) between `WATCH` and `EXEC`, the transaction aborts and `EXEC` returns a null reply instead of running the queued commands.",{"id":189,"topic":9,"difficulty":176,"body":190,"options":191,"correct_key":139,"explanation":200},"019f89ea-06a3-7118-b65b-4f3d45a0bff4","```\nWATCH balance\nval = GET balance\nMULTI\nSET balance \u003Cval - 10>\nEXEC\n```\nWhat happens if another client changes `balance` right after the `GET` but before `EXEC`?",[192,194,196,198],{"key":136,"text":193},"`EXEC` runs anyway, overwriting the other client's change with the stale value",{"key":139,"text":195},"`EXEC` returns null (nil array), and the `SET` is never applied",{"key":142,"text":197},"Redis merges both writes automatically using the latest value",{"key":145,"text":199},"The `WATCH` call itself raises an error at that point","Because `balance` was modified after `WATCH` and before `EXEC`, the transaction aborts: `EXEC` returns a nil reply, and none of the queued commands (the `SET`) run. The application must detect this and retry.",{"id":202,"topic":9,"difficulty":176,"body":203,"options":204,"correct_key":136,"explanation":213},"019f89ea-06a3-7d0b-9843-0bca444792fa","Does Redis support rolling back individual commands inside a transaction if one of them fails at runtime (e.g. wrong type error)?",[205,207,209,211],{"key":136,"text":206},"No — other commands in the same `EXEC` still run; Redis transactions have no per-command rollback",{"key":139,"text":208},"Yes — a runtime failure automatically undoes every earlier successful command and prevents all later queued commands from running",{"key":142,"text":210},"Yes, but only if `WATCH` was used before `MULTI`",{"key":145,"text":212},"No — the entire connection is closed and the client must reconnect","Redis transactions don't support rollback. If a command fails at runtime during `EXEC` (e.g. calling a list command on a string key), the other queued commands still execute; only that one command's error is reported in the reply array.",{"fields":215,"seniorities":391,"interview_shapes":392,"locales":397,"oauth":399,"question_count":402,"coach_enabled":403,"jd_match_enabled":403},[216,241,261,278,302,315,324,343,365,372,378,385],{"key":217,"name_tr":218,"name_en":218,"sort":132,"specializations":219},"backend","Backend",[220,223,226,229,232,235,238],{"key":221,"name":222,"field":217},"general","Genel",{"key":224,"name":225,"field":217},"go","Go",{"key":227,"name":228,"field":217},"python","Python",{"key":230,"name":231,"field":217},"java","Java",{"key":233,"name":234,"field":217},"csharp","C#\u002F.NET",{"key":236,"name":237,"field":217},"nodejs","Node.js",{"key":239,"name":240,"field":217},"php","PHP",{"key":242,"name_tr":243,"name_en":243,"sort":176,"specializations":244},"frontend","Frontend",[245,246,249,252,255,258],{"key":221,"name":222,"field":242},{"key":247,"name":248,"field":242},"javascript","JavaScript",{"key":250,"name":251,"field":242},"typescript","TypeScript",{"key":253,"name":254,"field":242},"react","React",{"key":256,"name":257,"field":242},"vue","Vue",{"key":259,"name":260,"field":242},"angular","Angular",{"key":262,"name_tr":263,"name_en":263,"sort":264,"specializations":265},"fullstack","Fullstack",3,[266,267,268,269,270,271,272,273,274,275,276,277],{"key":221,"name":222,"field":262},{"key":224,"name":225,"field":217},{"key":227,"name":228,"field":217},{"key":230,"name":231,"field":217},{"key":233,"name":234,"field":217},{"key":236,"name":237,"field":217},{"key":239,"name":240,"field":217},{"key":247,"name":248,"field":242},{"key":250,"name":251,"field":242},{"key":253,"name":254,"field":242},{"key":256,"name":257,"field":242},{"key":259,"name":260,"field":242},{"key":279,"name_tr":280,"name_en":280,"sort":281,"specializations":282},"devops-cloud","DevOps \u002F Cloud",4,[283,284,287,290,293,296,299],{"key":221,"name":222,"field":279},{"key":285,"name":286,"field":279},"aws","AWS",{"key":288,"name":289,"field":279},"gcp","GCP",{"key":291,"name":292,"field":279},"azure","Azure",{"key":294,"name":295,"field":279},"kubernetes","Kubernetes",{"key":297,"name":298,"field":279},"terraform","Terraform",{"key":300,"name":301,"field":279},"linux","Linux",{"key":303,"name_tr":304,"name_en":304,"sort":305,"specializations":306},"ai-engineer","AI Engineer",5,[307,308,309,312],{"key":221,"name":222,"field":303},{"key":227,"name":228,"field":303},{"key":310,"name":311,"field":303},"llm-rag","LLM\u002FRAG",{"key":313,"name":314,"field":303},"mlops","MLOps",{"key":5,"name_tr":316,"name_en":6,"sort":317,"specializations":318},"Veritabanı",6,[319,320,321,322,323],{"key":221,"name":222,"field":5},{"key":124,"name":125,"field":5},{"key":121,"name":122,"field":5},{"key":117,"name":118,"field":5},{"key":127,"name":128,"field":5},{"key":325,"name_tr":326,"name_en":327,"sort":328,"specializations":329},"mobile","Mobil","Mobile",7,[330,331,334,337,340],{"key":221,"name":222,"field":325},{"key":332,"name":333,"field":325},"ios-swift","iOS (Swift)",{"key":335,"name":336,"field":325},"android-kotlin","Android (Kotlin)",{"key":338,"name":339,"field":325},"flutter","Flutter",{"key":341,"name":342,"field":325},"react-native","React Native",{"key":344,"name_tr":345,"name_en":346,"sort":347,"specializations":348},"security","Güvenlik","Security",8,[349,350,353,356,359,362],{"key":221,"name":222,"field":344},{"key":351,"name":352,"field":344},"appsec","AppSec",{"key":354,"name":355,"field":344},"offensive-pentest","Offensive \u002F Pentest",{"key":357,"name":358,"field":344},"cloud-security","Cloud Security",{"key":360,"name":361,"field":344},"devsecops","DevSecOps",{"key":363,"name":364,"field":344},"blue-team-incident","Blue Team \u002F Incident",{"key":366,"name_tr":367,"name_en":368,"sort":369,"specializations":370},"qa-test-automation","QA \u002F Test Otomasyonu","QA \u002F Test Automation",9,[371],{"key":221,"name":222,"field":366},{"key":373,"name_tr":374,"name_en":374,"sort":375,"specializations":376},"data-engineer","Data Engineer",10,[377],{"key":221,"name":222,"field":373},{"key":379,"name_tr":380,"name_en":381,"sort":382,"specializations":383},"game-dev","Oyun Geliştirme","Game Development",11,[384],{"key":221,"name":222,"field":379},{"key":386,"name_tr":387,"name_en":387,"sort":388,"specializations":389},"ml-engineer","ML Engineer",12,[390],{"key":221,"name":222,"field":386},[14,15,16],{"junior":393,"mid":395,"senior":396},{"questions":394,"median_sec":3},20,{"questions":394,"median_sec":3},{"questions":394,"median_sec":3},[398,10],"tr",[400,401],"google","github",21750,true]