貌似上面一种情况是针对oracle优化器的,sql server优化器还没那么智能可以识别出这种参数探嗅的模式,只能对语句一模一样的SQL进行软解析。这里有特殊,除非是明显不会影响查询计划的参数化,比如用主键来做等于限制,无论怎么样都是做cluster index seek,所以SQL SERVER优化器就自动参数化了。 select * from dbo.dimst...
在ComputeColumn表上创建计算列并创建一个非聚集索引 ALTER TABLE dbo.ComputeColumn ADD FullName AS (FirstName+''+LastName) GO CREATE NONCLUSTERED INDEX IX_CompCol_CityTrim ON dbo.ComputeColumn (FullName) GO 在ComputeColumnCompare表上创建计算列 ALTER TABLE dbo.ComputeColumnCompare ADD FullName_P A...
CPU time=0ms, elapsed time=14ms.Table'computed_column_test_computed'. Scancount0, logical reads302521, physical reads0,read-ahead reads0, lob logical reads0, lob physical reads0, lobread-ahead reads0.Table'Numbers'. Scancount1, logical reads487, physical reads0,read-ahead reads0, lob log...
When optimizing your database server, you need to tune the performance of individual queries. This is as important as—perhaps even more important than—tuning other aspects of your server installation, that affect performance, such as hardware and software configurations....
SQL Server的复制功能将数据从发布服务器复制到订阅服务器,提供三种复制类型: 事务复制,用于服务器之间的环境,当更改发生时,从发布服务器将更改传送到订阅服务器; 合并复制,用于服务器到客户端的环境或可能发生冲突情况下,数据可以在发布服务器或订阅服务器上更改并跟踪,之后进行同步; 快照复制,用于数据更新不频繁或不...
With Sql server 2000 and 2005 computed columns can be use to improve the performance of queries since without the computed columns, indexes cannot be used as explained in the following blog by one of our Escalation Engineer ...
Let's use an example. Frequently, we got cases from customers who are not aware of performance implications and do just that. If you have query like below. It poses challanges to SQL Server optimizer. It can't use index on c1 to do any seeks. ...
Which of PostgreSQL or SQL Server is easier to use? Compare the ease of use of PostgreSQL vs. MSSQL 中文:那个数据库更方便使用 PostgreSQL 是一种先进的面向对象的关系型数据库管理系统,使用了结构化查询语言 (SQL) 以及其自己的过程语言 PL/pgSQL。PostgreSQL 易于使用,具有完整的关系型数据库管理系统(...
While the operation is running, performance can slow. However, once data is compressed, query performance improves. For syntax examples, see Examples - Columnstore reorganize. Notă Starting with SQL Server 2019 (15.x), Azure SQL Database, and Azure SQL Managed Instance, the tup...
Performance of Calculated Columns The formula for a calculated column can be more resource-intensive than the formula used for a measure. One reason is that the result for a calculated column is always calculated for each row in a table, whereas a measure is only calculated for the cel...