sql server sparse columns performance

With the introduction of new sparse column functionality in SQL Server 2008, it is now possible to declare a column as a sparse column and to enter a null value in the column at any time and it will not consume any space. One technique is to find out when to determine whether a column is defined as a

Original: SQL Server performance optimization included columnsSQL Server performance optimization included columnsGuide: Data number optimization query has always been a relatively hot topic, niche in this area can only be regarded as an introductory student. ThisOh, God, we

SQL Server performance optimization included columnsGuide: Data number optimization query has always been a relatively hot topic, niche in this area can only be regarded as an introductory student. ThisOh, God, we'll talk about it. The function of the database contains columns and the optimization effectquote an explan

Label:Sparse file (sparse files) is not an attribute of SQL Server. It belongs to an attribute of the NTFS file system of Windows. If the data in a large file contains a large amount of "0 data" (which should be viewed from the binary), such a file can be called a sparse file. If you look at this file from a two-dimens

Description of pseudo columns and pseudo columns in the SQL Server database. Pseudo columns in SQL Server In the afternoon, someone in the QQ group was discussing (non-clustered) index

Pseudo-Columns in SQL ServerQQ Group in the afternoon to see someone in the discussion (nonclustered) index storage,Say, for a clustered index table, the nonclustered index stores the index key value + the clustered index key value; For a nonclustered index table, the index stores the index key value +rowid, which should be a common sense, which is not elaborated in detail.The main point here is that the RO

Label:If you set a column to identity when you create a new table, you can not display the specified value when inserting the data, and SQL Server automatically populates the value of that column. Create Table TblPerson1 ( IntIdentity(1,1Primarykey not Null , Nvarchar (null ) At this point, the following code can be used to insert data into the table. Although the Tblperson table has two

write cache exists and the algorithm is normal, RAID5 is even better than raid10, although there may not be much difference (here we should assume that there is a certain size of storage, enough write cache, and there is no bottleneck in the CPU for computing and verification ). This is because the raid check is completed in the cache. For example, for RAID 5 of four disks, you can calculate the check in the memory and write three data and one verification at the same time. Raid10 can only wr

Http://www.cnblogs.com/gaizai/archive/2010/01/11/1644358.html Before I start, I want to talk about several concepts. Overwrite Query] When an index contains all the columns referenced by a query, it is usually called "Overwrite query ". [Index coverage] If the returned data column is included in the index's key value, or included in the index's key value + clustered index's key value, no bookup lookup occurs because the index item is found, the requ

SQL Server performance optimization skills, SQL Server Performance Optimization 1. Select the most efficient table name sequence (only valid in the rule-based Optimizer) The SQL

database design Reasonable and standardized logical database design can produce optimal performance. A large number of narrow tables are a feature of the standard database. A small number of wide tables are non-standard data features. Highly standard databases are usually associated with complex table joint queries, which may damage the database performance. In any case,

SQL Server address search performance optimization and SQL server performance optimization This is an example of a long time ago. Now, I have no intention of discovering the materials, so I will take it out and try again. 1. Requi

Before opening a text, let's start with a few concepts. "Overwrite Query" When an index contains all the columns that a query references, it is often referred to as an "overwrite query." "Index Overlay" If the returned data column is contained in the key value of the index, or is contained in the key value of the indexed key value + clustered index, then Bookup Lookup does not occur because the desired data is found when the index entry is found,

Today, I investigated a defect in the project and found that SQL Server sorts the guid column andClusterSpecial processing of index. Two knowledge points are involved. One is how SQL Server sorts guid columns.AlgorithmImplementation. The second is the difference between cluster index and noncluster index. First, let's

Label:Original: SQL Server lists columns and properties for each tableWhen you need to organize a database help document, you might want to list the columns and their properties for each table in the library. This may be helpful in developing some interfaces or outsourcing to other companies. If you need someone to ope

For example: We import a customer's information, we know that the customer's name is Zhangshan, we want to know, in our business database (Eg:northwind), which of the data tables which fields set the name value Zhangshan, through the following SQL, This is what we can do, where the SQL search has been locally modified from the Web. One, the search data is a string type Applicable to search Text,ntext,varcha

for all representations of each data type2, Seed (seed) is the value assigned to the first row in the table, which defaults to 13, increment (increment) the increment between adjacent two identity values, which defaults to 1. Third, the creation and modification of the identity column, usually in Enterprise Manager and with Transact-SQL statements can be implemented, using Enterprise Management Manager is relatively simple, please refer to the online

Tags: complete data type T-SQL error ROM window http SQL Server 9.pngmodifying data columnsIn the development and production process, the spelling error of the column name or the change of the column name is required to manipulate the data table, in most cases it is not necessary to modify. There are several scenarios in which we cannot directly modify the data

Label:Data from the database in the work to export, but found that the exported Excel column names are field names (in English), to collect data on how to change the field name to Chinese names, and found that Oracle and SQL Server (SQLSERVER2008R2) is different, as follows: SQL Server database: system table: ---Get in

following is the optimization of the SQL statement in fact, SQL is not complex, but the data of these tables are slightly larger, but also nested inside more complex business logic, history after several rounds of "master" in the index of the whole side of the optimization, can also run normally but over time, the amount of data in the table is getting larger , boiled frog in warm water,