传统的关系数据库服务引擎往往并不是对超大量数据进行分析计算的最佳平台,为此,SQL Server中开发了分析服务引擎去对大笔数据进行分析计算.当然,对于数据的存放平台SQL Server数据库引擎而言,也是需要强大的数据处理能力的. 在SQL Server 2012时,SQL Server 引入了列存储索引,用以显著提供高传统数据仓库类型语句的性能,并在SQL Server 2014中做了进一步加强.本文将在对SQL Server 2012列存储索引简单介绍的基础上,进一步解释SQL Serve…
An index is used to speed up searching in the database. By default, when you create this table, your data will be stored on disk and sorted by the "Id" primary key column. This default sort is called the "Clustered Index". Affects the…
This is the last in a series of Postgres posts that Pat Shaughnessy wrote based on his presentation at the Barcelona Ruby Conference. You can also watch the video recording of the presentation. The series was originally published on his personal blog…
do not build indexes unless necessary. 索引是非常占资源的To maintain optimal performance, drop indexes that an application is not using. 不用的索引可以drop掉, 通过toad可以生成监控脚本, 监控一段时间内, 哪些脚本没有被使用 (ALTER INDEX MONITORING USAGE)什么时候创建索引 Consider indexing keys that appear…
Understanding the B-tree and hash data structures can help predict how different queries perform on different storage engines that use these data structures in their indexes, particularly for theMEMORY storage engine that lets you choose B-tree or ha…