記一次騰訊雲（西安）後臺開發面試經歷

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/7f/7f2f11ae0332ed24e3e493e2996e4e3b.jpeg","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"作者：z小趙"}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"★ "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"一枚用心堅持寫原創的“無趣”程序猿，在自身受益的同時也讓朋友們在技術上有所提升。"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"各位讀者朋友們還好嗎？是不是覺着有一段時間沒有看到我的新文章了？本篇文章總結一下最近發生的事情，主要有兩方面："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"其一：最近這段時間因爲公司組織架構的調整，身邊朋友走了挺多，內心躁動的我也有些不太安分了。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"​其二：女朋友在西安的工作確定了下來，加之房子也在西安，所以就萌生了回西安的想法。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"接下來就心儀公司的選擇和麪試經歷做一些簡單總結。希望對朋友們找工作，尤其是在西安準備嘗試騰訊雲的朋友們有所幫助。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"西安好找工作嗎？"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"答案是取決於你想去一個什麼樣的企業。自畢業以後一直覺得西安互聯網環境應該還不錯，有華爲、中興、360、京東等等一些不錯的國內的大廠，也有一些如 Thouhtworks 等等不錯的外企。但是最近和獵頭朋友交流以後發現，在西安想找到一個自己稱心如意的崗位，難度相對來說還是有些大的，下面是一些獵頭朋友反饋的目前西安的情況。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/e0/e095b87fe1d62640ae5942667ef7ef7c.jpeg","alt":null,"title":"","style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"我對於這個回覆還是持有一些疑問的，於是自己親自逛了 Boss 直聘，發現情況基本上確實差不多。造成這種現象我認爲基本上有兩點，其一是自己對於市場的期望值過高（可能因爲在一線城市待習慣了），其二是相對可選擇的空間還是比較少。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"對市場有了一些瞭解之後，最後選擇去試試騰訊雲西安的崗位，我選擇的是 Java 開發，偏向於高併發、分佈式相關的工作，下面是面試過程中面試官提問的一些問題，希望能夠對正在西安找工作或者有跳槽想法的朋友有所幫助。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"面試涉及題目及答案"}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 1：自我介紹及項目經歷"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"關於這道題，每個人的項目經歷都不太一樣，所以各位朋友根據自己的實際情況來介紹吧，在這裏就不多介紹了。"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 2：看你項目介紹中大量使用了 Redis，那能不能介紹下 Redis 的主從同步機制呢？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"關於這道題，因爲我在之前的文章也分析過 Redis 主從同步的機制，所以我從 "},{"type":"text","marks":[{"type":"strong"}],"text":"完整重同步"},{"type":"text","text":" 和 "},{"type":"text","marks":[{"type":"strong"}],"text":"部分重同步"},{"type":"text","text":" 兩個階段去分析的，結果也得到了面試官的認可。詳細的完整重同步和部分重同步機制原理是什麼樣的，在這裏就不展開介紹了，附上鍊接朋友們自行查看吧。"},{"type":"link","attrs":{"href":"https://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247484394&idx=1&sn=7423bc0983bdcfc48dcaaf14c700b93d&chksm=e8eb7a7edf9cf368629b751280337f350ddf383cd8cb410491aa6fcd623e84f5c072bd4ea87e&token=267415244&lang=zh_CN&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"主從同步原理，點擊查看"}],"marks":[{"type":"strong"}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 3：你們項目中 Redis 的內存使用和過期數據是怎麼做的？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這是兩道題，先來說說內存是怎麼設計的，首先我們是按照業務維度去評估資源內存的使用量和 QPS 兩個維度去評估 Redis 該部署多少資源，然後提到了業務中 Redis 的部署方式及原因。然後在聊到過期數據的剔除策略，這些在之前的文章也有介紹過，附上鍊接朋友們自行查看吧。"},{"type":"link","attrs":{"href":"https://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247484290&idx=1&sn=9e4d47ba8042543c9718ebcb766c8df3&chksm=e8eb7a16df9cf30057e2ccbc224f336a32b92b3342c461c8d54572913bb9cbac095266f5e4d4&token=267415244&lang=zh_CN&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"緩存過期剔除策略"}],"marks":[{"type":"strong"}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 4：看你在實際項目中使用 Streaming 做了一些實時推薦的項目，能介紹下嗎？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"我們的部分實時推薦項目使用的是 Steaming，其通過對 Kafka 的 Consumer 進行了二次開發封裝，屏蔽了 Kafka 不同版本對於業務的影響，同時也可以用 Steaming 去對接不同的數據源，比如現在也支持 xx 數據源的消費（因爲業務比較那啥，在這裏就不說明了）"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 5：既然使用了 Kafka，你知道爲什麼 Kafka 那麼快嗎？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這道題之前在 Kafka 常見面試題中有提到過，這裏需要補充一點是，Kafka 的“零拷貝”機制需要朋友在深入研究下，在之前的文章裏面沒有深入解釋過這個點，剩餘的其他方面附上鍊接朋友們自行查看吧。"},{"type":"link","attrs":{"href":"https://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247484048&idx=1&sn=2de06942948b02842fd042e7783cbc61&chksm=e8eb7b04df9cf2121a98984fae0207d422b9d643a2c3ff4d7c91cabfe2e8b4d530a62c376035&token=267415244&lang=zh_CN&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"Kafka 爲什麼那麼快"}],"marks":[{"type":"strong"}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 6：使用 Kafka 有遇到過重複消費的情況嗎？你們是怎麼解決的？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"有遇到過，這裏補充一點，因爲業務形態所決定消息重複消費產生的影響不是特別嚴重，所以在一定程度上可以暫時接受，後續通過一些手段去解決了，解決辦法之前介紹過如何處理，懶得在這裏繼續重複了，直接看鏈接吧。"},{"type":"link","attrs":{"href":"https://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247484078&idx=1&sn=3b0e754674804d61bde1df498f0bd092&chksm=e8eb7b3adf9cf22c370346b0eb2aa516f517daf4d0fa5977f41412d64f22cfe86f8eec90c58c&token=267415244&lang=zh_CN&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"Kafka 重複消費怎麼辦"}],"marks":[{"type":"strong"}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 7：關於項目咱們先聊這麼多，出個題吧，怎麼實現一個阻塞隊列？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"網上解決辦法一大堆，大家自行百度吧，需要額外注意的一個點是，如何提高其併發處理的能力（這點我沒答上來，期待朋友們留言一起來探討）"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 8：MySQL 熟悉嗎？MySQL 事務是什麼？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"ACID 準備下，時間不多了，直接略過，準備面試的朋友們記得準備一下哈。簡單聊了下 讀未提交、讀已提交、重複讀、序列化幾種情況。需要額外再準備下業務中使用的事務隔離級別是怎麼用的（我在項目中使用的 MySQL 不多，面試官也沒有多問，主要是一個小時的面試時間快到了，哈哈哈）"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 9：知道 MySQL 的 MVCC 機制嗎？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"平時基本不用 MySQL，這個沒答出來，之後瞭解了下 InnoDB 大概是通過 undo log 和版本號機制來實現的（怪我沒有充分準備就面試了，哈哈，自己活該）"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 9：JVM 的垃圾回收機制瞭解嗎？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"標記-清楚算法、複製算法、標記-壓縮算法、分代收集算法的實現原理。"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"面試官提問 10：項目中用的是 CMS 垃圾回收器嗎？爲什麼要分爲四個階段？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"初始標記，併發標記，重新標記，併發清理四階段，系統要求快速響應低延遲，對於多核 CPU 性能更佳等方面去回答即可，網上文章很多，這裏不多贅述了。"}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"總結"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"以上內容基本上就是這次面試遇到了問題了，基本上圍繞這項目來問的，問題也不是很難，大部分問題在之前的文章了自己也都研究過，所以答起來就很輕鬆。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"希望通過本文能夠對正在準備面試的朋友有所幫助，另外也希望不着急的朋友們平時好好打基礎，面試的時候大概準備下基本上問題就不大了。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"通過本次面試也知道自己對於 MySQL 這塊比較雞肋，下個系列開始搞 MySQL，繼續查漏補缺，幹就完了。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"往期精選"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "},{"type":"link","attrs":{"href":"http://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247484512&idx=1&sn=7d8bad330ec0d65ddcd8c15f1d9756ed&chksm=e8eb7df4df9cf4e25fb9297e74416c0f98ef0381483259f1faa16447fa4dec0dda2e6a13f099&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"Redis系列（八）：緩存到底該如何做到高可用？"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "},{"type":"link","attrs":{"href":"http://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247484500&idx=1&sn=d5440c36669bdb8dd8b2d66136cb1333&chksm=e8eb7dc0df9cf4d61d546a6faa4e278f73a51f368b8e903c757696591edb716fa00289808471&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"Redis系列（七）：緩存只是讀寫回種這麼簡單嗎？如果是，那麼請你一定看看這篇文章！"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "},{"type":"link","attrs":{"href":"http://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247484078&idx=1&sn=3b0e754674804d61bde1df498f0bd092&chksm=e8eb7b3adf9cf22c370346b0eb2aa516f517daf4d0fa5977f41412d64f22cfe86f8eec90c58c&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"Kafka系列10：面試題是否有必要深入瞭解其背後的原理？我覺得應該刨根究底（下）"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "},{"type":"link","attrs":{"href":"http://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247483919&idx=1&sn=ee4c393dabadcecd51b34380425d227a&chksm=e8eb7b9bdf9cf28da20a8083d772d6744850256e7b338aa79225889c69f8395ab6019808d946&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"Kafka系列第7篇：你必須要知道集羣內部工作原理的一些事！"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "},{"type":"link","attrs":{"href":"http://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247484476&idx=1&sn=9ac5d9fda3567e8a970a3608935a9fd9&chksm=e8eb7da8df9cf4be9df41dedde5d768ee3218d8ee9919422044ce7e4e60f3d44ce56a5470d73&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"Redis系列（六）：你說要看Redis線程模型？安排"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}