恆生電子發佈金融分佈式數據庫LightDB，兼容Oracle、MySQL

{"type":"doc","content":[{"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":"12月1日，在2021 LIGHT開發者雲大會上，恆生電子正式發佈自主研發的金融分佈式數據庫LightDB。LightDB採用分佈式架構，計算和存儲分離，支持多存儲引擎，多副本高可用，同時內置數據庫管理平臺，通過與其他數據庫連接進行備份。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"LightDB接口分三類：第一種是通常的訪問協議；第二種是直連到計算節點的模式；第三種爲極速的模式，達微秒級，可以連到可插拔的存儲層接口。LightDB 引入了Coordinator，來負責接收和分析用戶的查詢請求，並調度到不同的節點上執行。Coordinator有一主一備，實時同步數據。數據存儲可以是行式存儲、列式存儲，也可以是內存式存儲。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"LightDB底層設置了EM-Agent，來進行運維管理、主機監控、數據庫的監控，同時做一些告警和備份修復，還能安排一些定時任務。另外，LightDB安裝了同步複製工具，可以把其他數據庫的數據同步複製到LightDB當中。"}]},{"type":"image","attrs":{"src":"https:\/\/static001.infoq.cn\/resource\/image\/16\/5c\/169b090cdd7237a88f766c74dea74f5c.png","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":"center","origin":null},"content":[{"type":"text","text":"Light DB架構"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"據恆生研究院院長白碩介紹，金融領域對數據庫的需求主要在兩方面：一是技術特性，如穩定、可靠、性能、安全等；二是廠商提供的運維技術支持，如故障診斷、易運維性、易安裝性、易遷移性等。企業採購數據庫並不是買軟件，更多是廠商在運維、配置和優化等方面的服務。新廠商提供的服務必須可以與原來數據庫廠商旗鼓相當。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"通過需求倒推，恆生電子基於開源的PostgreSQL穩定版，研發出了LightDB。 LightDB保留了PostgreSQL的核心性能，但在穩定性、高性能方面做了進一步優化，恆生電子也自主研發了監控、運維、分析等組件完善數據庫的各項功能。官方表示，LightDB具有金融級穩定性。所謂“金融級穩定性”是指擁有持續的、可預期的高性能，比如能夠有效防止TPS等指標的抖動。LightDB除了做數據冗餘外，也進行了容災備份。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"數據對一致性需求並不相同。副本必須強一致性，但事務一致性可以多階段解決。多版本一致性則要看實際情況。整個系統裏，可能20%的數據流量需要保持強一致性，剩下80%的數據對一致性要求可能沒有那麼嚴。因此，LightDB支持從表、到事務、到實例層面的差異化一致性控制，設立了一致性等級，來確保性能訴求和一致性訴求在解耦基礎上的兼顧。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在白碩看來，分佈式應該是特性而非屬性。分佈式架構是爲了解決非常大容量的負載均衡問題，而不是一種標籤。用戶不需要一味追求分佈式架構，根據自身情況來定就可以。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"企業更換數據庫常常面臨兩個重要限定條件：應用和數據。更換數據庫的重點是更換數據庫管理系統。不同數據庫之間標準不同，實現平滑替換就變得很難，但企業並不想因更換數據庫而影響原有應用的運行。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"因此，爲了更加兼容和易用，LightDB通過SQL解析等方式，兼容了Oracle和MySQL的常用特性。“它們都有廣泛的用戶羣，用戶可能也有自己的研發習慣，通過兼容可以把這些習慣帶到LightDB當中。”白碩表示。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在運維方面，根據DBA 提出的一些痛點問題，恆生總結出了一套告警體系，並內置在LightDB中。這套預警體系可以幫助DBA和運維更快地定位到具體問題，如容量接近上限等，同時對數據庫管理系統進行監控和分析。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"白碩透露，LightDB目前優先適配私有部署的應用。當前的雲應用都需要在合規前提下進行，因此雲應用市場佔比份額還比較低，並不是行業重點。“LightDB未來的發展會和雲應用的實際推廣步驟相一致，雲應用高潮到來之前，我們會做好雲版本的準備。”"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"據悉，LightDB支持麒麟Linux、openEuler等國產操作系統，支持華爲鯤鵬ARM，海光x86處理器等國產處理器，並已成功通過中國信通院的分佈式事務型數據庫基礎能力評測。目前，LightDB已陸續應用於恆生TA產品及恆生內部的效能平臺等系統，並正與外部金融機構客戶一起探索國產數據庫應用場景。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"LightDB 版本從預覽版起步，穩定下來的部分固化爲企業版，應用在行業各種場景應用。同時，穩定下來的這部分核心代碼也將用來回饋社區，LightDB 將持續兼容社區的新版本。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"國內當前數據庫主要分三類：主流商業數據庫、開源數據庫和國產數據庫。雖然國產數據庫正在發展，但對於技術選型非常慎重的金融行業來說，主流商業數據庫仍佔據了大部分市場。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"根據恆生電子發佈的《2022金融科技趨勢研究報告》，在金融行業對低時延等的特別需求下，金融數據庫將朝着分佈式、多元化、內存化方向發展。關係型數據庫保持市場主體地位的同時，內存數據庫、時序數據庫、圖數據庫等非關係型數據庫的比重將提升，並且開源和國產化數據庫也將逐步被應用到金融核心系統。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"“目前雖然有國產數據庫或開源數據庫有替代主流商業數據庫的趨勢，但也是要一步一步來的。”白碩說道。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]}]}