Socrates: The New SQL Server in the Cloud Socarates是微软发表于SIGMOD 2019的一篇关于云数据库的文章。在Amazon Aurora之后,微软也开发了基于存储计算分离的云数据库,本文主要介绍它的架构细节。一、Motivation 随着DBaaS越来越… 数据库小白发表于分布式系统... Azure Data Lake Store: A Hyperscale Distributed ...
in是把外表和内表作hash连接,而exists是对外表作loop循环,每次loop循环再对内表进行查询,一直以来认为exists比in效率高的说法是不准确的。 如果查询的两个表大小相当,那么用in和exists差别不大;如果两个表中一个较小一个较大,则子查询表大的用exists,子查询表小的用in; 例如:表A(小表),表B(大表) 代码语...
《高性能MySQL》 里面提及用in这种方式可以有效的替代一定的range查询,提升查询效率,因为在一条索引里面,range字段后面的部分是不生效的(ps.需要考虑 ICP)。MySQL优化器将in这种方式转化成 n*m 种组合进行查询,最终将返回值合并,有点类似union但是更高效。
The database-as-a-service paradigm in the cloud (DBaaS) is becoming increasingly popular. Organizations adopt this paradigm because they expect higher security, higher availability, and lower and more flexible cost with high performance. It has become clear, however, that these expectations cannot ...
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difficult maintenance tasks are now possible to automate, and conveniently encapsulated within the common Azure portal experience. Simply author a PowerShell Workflow (called a “runbook” in Azure Automation), upload it to the cloud, and schedule when you want the runbook to execute. It’s that...
之前CDH版本执行无误的SQL,在CDH集群升级到7.1.7版本后执行失败,具体报错信息如下:ParseException: Syntax error in line 34:\nsum(enable) as 辅助\n ^\nEncountered: ENABLE\nExpected: ALL, CASE, CAST, DATE, DEFAULT, DISTINCT, EXISTS, FALSE, IF, INTERVAL, LEFT, NOT, NULL, REPLACE, RIGHT, TRUNCAT...
Spotlight is a solution provided by Quest for the monitoring of SQL Server deployments in their customers’ data centers and in the cloud. They leverage In-Memory OLTP to speed up the processing of requests and events such that Quest’s customers learn about any potential issues in their enviro...
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Amazon RDS ermöglicht unter anderem die Bereitstellung mehrerer Editionen von SQL Servern. Entdecken Sie, wie Amazon RDS für SQL Server das Erstellen, den Betrieb und die Skalierung von SQL Server-Bereitstellungen in der Cloud vereinfacht.