恒生电子发布金融分布式数据库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开发者云大会上，恒生电子正式发布自主研发的金融分布式数据库LightDB。LightDB采用分布式架构，计算和存储分离，支持多存储引擎，多副本高可用，同时内置数据库管理平台，通过与其他数据库连接进行备份。"}]},{"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接口分三类：第一种是通常的访问协议；第二种是直连到计算节点的模式；第三种为极速的模式，达微秒级，可以连到可插拔的存储层接口。LightDB 引入了Coordinator，来负责接收和分析用户的查询请求，并调度到不同的节点上执行。Coordinator有一主一备，实时同步数据。数据存储可以是行式存储、列式存储，也可以是内存式存储。"}]},{"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底层设置了EM-Agent，来进行运维管理、主机监控、数据库的监控，同时做一些告警和备份修复，还能安排一些定时任务。另外，LightDB安装了同步复制工具，可以把其他数据库的数据同步复制到LightDB当中。"}]},{"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架构"}]},{"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":"据恒生研究院院长白硕介绍，金融领域对数据库的需求主要在两方面：一是技术特性，如稳定、可靠、性能、安全等；二是厂商提供的运维技术支持，如故障诊断、易运维性、易安装性、易迁移性等。企业采购数据库并不是买软件，更多是厂商在运维、配置和优化等方面的服务。新厂商提供的服务必须可以与原来数据库厂商旗鼓相当。"}]},{"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":"通过需求倒推，恒生电子基于开源的PostgreSQL稳定版，研发出了LightDB。 LightDB保留了PostgreSQL的核心性能，但在稳定性、高性能方面做了进一步优化，恒生电子也自主研发了监控、运维、分析等组件完善数据库的各项功能。官方表示，LightDB具有金融级稳定性。所谓“金融级稳定性”是指拥有持续的、可预期的高性能，比如能够有效防止TPS等指标的抖动。LightDB除了做数据冗余外，也进行了容灾备份。"}]},{"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":"数据对一致性需求并不相同。副本必须强一致性，但事务一致性可以多阶段解决。多版本一致性则要看实际情况。整个系统里，可能20%的数据流量需要保持强一致性，剩下80%的数据对一致性要求可能没有那么严。因此，LightDB支持从表、到事务、到实例层面的差异化一致性控制，设立了一致性等级，来确保性能诉求和一致性诉求在解耦基础上的兼顾。"}]},{"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":"在白硕看来，分布式应该是特性而非属性。分布式架构是为了解决非常大容量的负载均衡问题，而不是一种标签。用户不需要一味追求分布式架构，根据自身情况来定就可以。"}]},{"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":"企业更换数据库常常面临两个重要限定条件：应用和数据。更换数据库的重点是更换数据库管理系统。不同数据库之间标准不同，实现平滑替换就变得很难，但企业并不想因更换数据库而影响原有应用的运行。"}]},{"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，为了更加兼容和易用，LightDB通过SQL解析等方式，兼容了Oracle和MySQL的常用特性。“它们都有广泛的用户群，用户可能也有自己的研发习惯，通过兼容可以把这些习惯带到LightDB当中。”白硕表示。"}]},{"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":"在运维方面，根据DBA 提出的一些痛点问题，恒生总结出了一套告警体系，并内置在LightDB中。这套预警体系可以帮助DBA和运维更快地定位到具体问题，如容量接近上限等，同时对数据库管理系统进行监控和分析。"}]},{"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":"白硕透露，LightDB目前优先适配私有部署的应用。当前的云应用都需要在合规前提下进行，因此云应用市场占比份额还比较低，并不是行业重点。“LightDB未来的发展会和云应用的实际推广步骤相一致，云应用高潮到来之前，我们会做好云版本的准备。”"}]},{"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":"据悉，LightDB支持麒麟Linux、openEuler等国产操作系统，支持华为鲲鹏ARM，海光x86处理器等国产处理器，并已成功通过中国信通院的分布式事务型数据库基础能力评测。目前，LightDB已陆续应用于恒生TA产品及恒生内部的效能平台等系统，并正与外部金融机构客户一起探索国产数据库应用场景。"}]},{"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 版本从预览版起步，稳定下来的部分固化为企业版，应用在行业各种场景应用。同时，稳定下来的这部分核心代码也将用来回馈社区，LightDB 将持续兼容社区的新版本。"}]},{"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":"国内当前数据库主要分三类：主流商业数据库、开源数据库和国产数据库。虽然国产数据库正在发展，但对于技术选型非常慎重的金融行业来说，主流商业数据库仍占据了大部分市场。"}]},{"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":"根据恒生电子发布的《2022金融科技趋势研究报告》，在金融行业对低时延等的特别需求下，金融数据库将朝着分布式、多元化、内存化方向发展。关系型数据库保持市场主体地位的同时，内存数据库、时序数据库、图数据库等非关系型数据库的比重将提升，并且开源和国产化数据库也将逐步被应用到金融核心系统。"}]},{"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":"“目前虽然有国产数据库或开源数据库有替代主流商业数据库的趋势，但也是要一步一步来的。”白硕说道。"}]},{"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":" "}]}]}